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Preparing Cupric Chloride Etching Solution

Jim Higgins
 

OVERVIEW:

This is a simple procedure for preparing 1 liter of cupric chloride etching solution. The tradeoff for the simplicity is a bit of patience as it may take a while to complete the preparation. The value of this patience is that the resulting solution won't be overburdened with hydrochloric acid and thus won't be as smelly and as corrosive to materials around it as more quickly prepared solutions tend to be. It also won't have any residual hydrogen peroxide which will result in a very slightly lower tendency to undercut your PCB traces. That last effect is really quite small, but why not? Also, since we won't be depending on the presence of H2O2 once the etching solution is prepared, we don't have to worry about over diluting our solution by trying to regenerate it with the weak 3% H2O2 commonly available in drugstores. We'll be regenerating with an air bubbler, which can serve double duty to agitate the solution when etching.


MATERIALS:

One large (at least 2 liter/0.5 gallon) glass container with a plastic lid. A 1/2 gallon "iced tea" jar with a plastic lid (plastic liner or no liner) and a small pop open spout would be ideal because you can open the spout to insert a fritted glass bubbler for use in rejuvenating the solution after use. If you need more than 1 liter (1 qt) of solution, consider using a larger container and increase the amounts of materials below accordingly. I suggest the container be only about half full when done. Only partially full plus a small opening in the lid keeps any spray resulting from regeneration by air bubbling inside the glass container.

One small aquarium pump. The cheap vibrating kind is fine.

One fritted glass bubbler, preferably long enough that it can reach the bottom of the large glass container with at least an inch or more of glass tube sticking out - preferably. If you can't find one that long, then your plastic tubing will extend into the container. I don't like that, but that's just me.

Plastic tubing to connect the pump to the fritted glass bubbler. I like enough tubing that I can place my pump higher then the top of my jar. Not likely the solution will syphon out if the pump is lower, but it's 100% impossible if it's higher.

200 grams (7 oz) copper wire, copper pipe or other pure copper. I used solid copper wire, but stranded copper will dissolve faster for those in a hurry. Pennies (even the old type) and misc plumbing hardware aren't pure copper and are unsuitable. 200 gms of copper is about 14 feet of #10 copper wire.

Hydrochloric (muriatic) acid concrete driveway cleaner, free of detergent or other additives. (Read the label.) This should be 32 - 37% HCl. Weaker will work, but will require more. You can get this at Home Depot, Lowes and assorted hardware stores. It will probably cost more at pool supply places.

Hydrogen peroxide. The typical 3% solution from the drugstore is fine. You only need a few ounces.


SOLUTION PREPARATION:

Pour 1 liter (4-1/4 cups) of water into your container and mark the level on the outside of the container. Pour out the water. This is the level you will want to maintain later after etching and rejuvenating.

Add the copper to the glass container.

Place 0.6 liters (2.5 cups) of hydrochloric acid in the glass container.

Add 0.1 liter (0.5 cup) of hydrogen peroxide. This should be all the hydrogen peroxide you'll ever need.

The copper wire will begin dissolving as evidenced by a green color forming in the solution and bubbles being generated on the surface of the copper wire.

Place the lid on the container, open the spout and insert the fritted glass bubbler connected to aquarium pump and begin bubbling to mix the solution.

Here's where patience comes in... continue bubbling until the copper wire is completely dissolved. If the solution becomes a brownish, possibly muddy, color, add 1oz of hydrochloric acid and continue bubbling until the wire is completely dissolved AND the solution is a deep emerald green. The color will be fairly dark, so hold the solution up to a bright light, or pour a bit into a smaller container, to gauge the color. If the acid you're using is on the weaker side, you may need to repeat the addition of a bit (less than an ounce this time) of HCl if several days of bubbling don't result in a deep emerald green color with no trace of a brownish or muddy color.

Dilute to 1 liter with water and that's it.

Use it as you'd use any solution to etch PCBs and pour the used solution back into the main glass container when done. Inspect for color each time you pour solution into your etching tank. (It should be easier to gauge the color in the etching tank because you won't be looking thru as much solution.) As long as it's emerald green or only slightly off color, it's good. No harm in bubbling to rejuvenate after every use, but not necessary until it's no longer a pure emerald green.

The amount of excess HCl in the solution is designed to be quite low to none. If excess HCl is present there's no avoiding some of it being driven off by bubbling, but at very low concentrations that amount is essentially negligible. For those whom I might consider overly concerned... you can have the greater peace of mind you desire by avoiding unnecessary rejuvenation... and when HCl must be added because the solution won't fully rejuvenate, you can add it in smaller increments than I recommend until the solution can be rejuvenated to a pure emerald green.

At some point you'll find you can't rejuvenate just by bubbling. When that happens, add 1oz (less if highly concerned about corrosive fumes) of hydrochloric acid and bubble until emerald green. Add less than an ounce if worried about corrosive fumes, but realize you may need to add several of those smaller amounts to fully rejuvenate.

Maintain the solution level in the glass container at 1 liter - or whatever your initial volume was by adding water if it falls lower. If you only add HCl very sparingly, you can easily find the volume of the solution doesn't increase because some water evaporates when bubbling.

Over time, depending how much etching you do, copper will build up in the solution. When this occurs you can remove a bit of solution (maybe 0.5 - 1 cup), pour it into a pint jar and set it somewhere to evaporate. Make up what you remove with water. If you accumulate any significant amount of copper chloride crystals in this jar, you can scrape it into a small freezer baggie and give it to someone who wants to use it to kick start his own etching solution. Just dissolve it in water and add a small bit of HCl and you have etching solution. Add copper wire to it and bubble air thru it, adding HCl until the wire dissolves and you have stronger etching solution. A weaker solution will etch a PCB, but may undercut a bit due to the much longer time it will take.

That's it.

Jim H
 

Thank you very much Jim. Great info and very helpful. I really appreciate it. :-) One question though, when I look up "fritted glass bubbler" I mainly find bongs. Where is a good place to buy a "fritted glass bubbler"??

Dave

On 3/22/2019 7:50 PM, Jim Higgins wrote:

OVERVIEW:

This is a simple procedure for preparing 1 liter of cupric chloride etching solution. The tradeoff for the simplicity is a bit of patience as it may take a while to complete the preparation. The value of this patience is that the resulting solution won't be overburdened with hydrochloric acid and thus won't be as smelly and as corrosive to materials around it as more quickly prepared solutions tend to be. It also won't have any residual hydrogen peroxide which will result in a very slightly lower tendency to undercut your PCB traces. That last effect is really quite small, but why not? Also, since we won't be depending on the presence of H2O2 once the etching solution is prepared, we don't have to worry about over diluting our solution by trying to regenerate it with the weak 3% H2O2 commonly available in drugstores. We'll be regenerating with an air bubbler, which can serve double duty to agitate the solution when etching.


MATERIALS:

One large (at least 2 liter/0.5 gallon) glass container with a plastic lid. A 1/2 gallon "iced tea" jar with a plastic lid (plastic liner or no liner) and a small pop open spout would be ideal because you can open the spout to insert a fritted glass bubbler for use in rejuvenating the solution after use. If you need more than 1 liter (1 qt) of solution, consider using a larger container and increase the amounts of materials below accordingly. I suggest the container be only about half full when done. Only partially full plus a small opening in the lid keeps any spray resulting from regeneration by air bubbling inside the glass container.

One small aquarium pump. The cheap vibrating kind is fine.

One fritted glass bubbler, preferably long enough that it can reach the bottom of the large glass container with at least an inch or more of glass tube sticking out - preferably. If you can't find one that long, then your plastic tubing will extend into the container. I don't like that, but that's just me.

Plastic tubing to connect the pump to the fritted glass bubbler. I like enough tubing that I can place my pump higher then the top of my jar. Not likely the solution will syphon out if the pump is lower, but it's 100% impossible if it's higher.

200 grams (7 oz) copper wire, copper pipe or other pure copper. I used solid copper wire, but stranded copper will dissolve faster for those in a hurry. Pennies (even the old type) and misc plumbing hardware aren't pure copper and are unsuitable. 200 gms of copper is about 14 feet of #10 copper wire.

Hydrochloric (muriatic) acid concrete driveway cleaner, free of detergent or other additives. (Read the label.) This should be 32 - 37% HCl. Weaker will work, but will require more. You can get this at Home Depot, Lowes and assorted hardware stores. It will probably cost more at pool supply places.

Hydrogen peroxide. The typical 3% solution from the drugstore is fine. You only need a few ounces.


SOLUTION PREPARATION:

Pour 1 liter (4-1/4 cups) of water into your container and mark the level on the outside of the container. Pour out the water. This is the level you will want to maintain later after etching and rejuvenating.

Add the copper to the glass container.

Place 0.6 liters (2.5 cups) of hydrochloric acid in the glass container.

Add 0.1 liter (0.5 cup) of hydrogen peroxide. This should be all the hydrogen peroxide you'll ever need.

The copper wire will begin dissolving as evidenced by a green color forming in the solution and bubbles being generated on the surface of the copper wire.

Place the lid on the container, open the spout and insert the fritted glass bubbler connected to aquarium pump and begin bubbling to mix the solution.

Here's where patience comes in... continue bubbling until the copper wire is completely dissolved. If the solution becomes a brownish, possibly muddy, color, add 1oz of hydrochloric acid and continue bubbling until the wire is completely dissolved AND the solution is a deep emerald green. The color will be fairly dark, so hold the solution up to a bright light, or pour a bit into a smaller container, to gauge the color. If the acid you're using is on the weaker side, you may need to repeat the addition of a bit (less than an ounce this time) of HCl if several days of bubbling don't result in a deep emerald green color with no trace of a brownish or muddy color.

Dilute to 1 liter with water and that's it.

Use it as you'd use any solution to etch PCBs and pour the used solution back into the main glass container when done. Inspect for color each time you pour solution into your etching tank. (It should be easier to gauge the color in the etching tank because you won't be looking thru as much solution.) As long as it's emerald green or only slightly off color, it's good. No harm in bubbling to rejuvenate after every use, but not necessary until it's no longer a pure emerald green.

The amount of excess HCl in the solution is designed to be quite low to none. If excess HCl is present there's no avoiding some of it being driven off by bubbling, but at very low concentrations that amount is essentially negligible. For those whom I might consider overly concerned... you can have the greater peace of mind you desire by avoiding unnecessary rejuvenation... and when HCl must be added because the solution won't fully rejuvenate, you can add it in smaller increments than I recommend until the solution can be rejuvenated to a pure emerald green.

At some point you'll find you can't rejuvenate just by bubbling. When that happens, add 1oz (less if highly concerned about corrosive fumes) of hydrochloric acid and bubble until emerald green. Add less than an ounce if worried about corrosive fumes, but realize you may need to add several of those smaller amounts to fully rejuvenate.

Maintain the solution level in the glass container at 1 liter - or whatever your initial volume was by adding water if it falls lower. If you only add HCl very sparingly, you can easily find the volume of the solution doesn't increase because some water evaporates when bubbling.

Over time, depending how much etching you do, copper will build up in the solution. When this occurs you can remove a bit of solution (maybe 0.5 - 1 cup), pour it into a pint jar and set it somewhere to evaporate. Make up what you remove with water. If you accumulate any significant amount of copper chloride crystals in this jar, you can scrape it into a small freezer baggie and give it to someone who wants to use it to kick start his own etching solution. Just dissolve it in water and add a small bit of HCl and you have etching solution. Add copper wire to it and bubble air thru it, adding HCl until the wire dissolves and you have stronger etching solution. A weaker solution will etch a PCB, but may undercut a bit due to the much longer time it will take.

That's it.

Jim H
Jim Higgins
 

Received from Dave at 3/23/2019 04:30 PM UTC:

Thank you very much Jim. Great info and very helpful. I really appreciate it. :-) One question though, when I look up "fritted glass bubbler" I mainly find bongs. Where is a good place to buy a "fritted glass bubbler"??

At your local pet/aquarium store. A fritted glass bubbler will be all glass... a glass tube with an enlarged porous end on it. Describe it like that if they don't understand "fritted glass." You don't want a tube with a porous ceramic stone glued onto it as the stone is liable to deteriorate in the solution. If you can't get a tube with a porous glass end, just a plain plastic tube with an open end will do, tho it will take longer to regenerate. Shouldn't be hard to find the fritted glass bubbler in any half decent aquarium store.

Jim H



Dave

On 3/22/2019 7:50 PM, Jim Higgins wrote:

OVERVIEW:

This is a simple procedure for preparing 1 liter of cupric chloride etching solution. The tradeoff for the simplicity is a bit of patience as it may take a while to complete the preparation. The value of this patience is that the resulting solution won't be overburdened with hydrochloric acid and thus won't be as smelly and as corrosive to materials around it as more quickly prepared solutions tend to be. It also won't have any residual hydrogen peroxide which will result in a very slightly lower tendency to undercut your PCB traces. That last effect is really quite small, but why not? Also, since we won't be depending on the presence of H2O2 once the etching solution is prepared, we don't have to worry about over diluting our solution by trying to regenerate it with the weak 3% H2O2 commonly available in drugstores. We'll be regenerating with an air bubbler, which can serve double duty to agitate the solution when etching.


MATERIALS:

One large (at least 2 liter/0.5 gallon) glass container with a plastic lid. A 1/2 gallon "iced tea" jar with a plastic lid (plastic liner or no liner) and a small pop open spout would be ideal because you can open the spout to insert a fritted glass bubbler for use in rejuvenating the solution after use. If you need more than 1 liter (1 qt) of solution, consider using a larger container and increase the amounts of materials below accordingly. I suggest the container be only about half full when done. Only partially full plus a small opening in the lid keeps any spray resulting from regeneration by air bubbling inside the glass container.

One small aquarium pump. The cheap vibrating kind is fine.

One fritted glass bubbler, preferably long enough that it can reach the bottom of the large glass container with at least an inch or more of glass tube sticking out - preferably. If you can't find one that long, then your plastic tubing will extend into the container. I don't like that, but that's just me.

Plastic tubing to connect the pump to the fritted glass bubbler. I like enough tubing that I can place my pump higher then the top of my jar. Not likely the solution will syphon out if the pump is lower, but it's 100% impossible if it's higher.

200 grams (7 oz) copper wire, copper pipe or other pure copper. I used solid copper wire, but stranded copper will dissolve faster for those in a hurry. Pennies (even the old type) and misc plumbing hardware aren't pure copper and are unsuitable. 200 gms of copper is about 14 feet of #10 copper wire.

Hydrochloric (muriatic) acid concrete driveway cleaner, free of detergent or other additives. (Read the label.) This should be 32 - 37% HCl. Weaker will work, but will require more. You can get this at Home Depot, Lowes and assorted hardware stores. It will probably cost more at pool supply places.

Hydrogen peroxide. The typical 3% solution from the drugstore is fine. You only need a few ounces.


SOLUTION PREPARATION:

Pour 1 liter (4-1/4 cups) of water into your container and mark the level on the outside of the container. Pour out the water. This is the level you will want to maintain later after etching and rejuvenating.

Add the copper to the glass container.

Place 0.6 liters (2.5 cups) of hydrochloric acid in the glass container.

Add 0.1 liter (0.5 cup) of hydrogen peroxide. This should be all the hydrogen peroxide you'll ever need.

The copper wire will begin dissolving as evidenced by a green color forming in the solution and bubbles being generated on the surface of the copper wire.

Place the lid on the container, open the spout and insert the fritted glass bubbler connected to aquarium pump and begin bubbling to mix the solution.

Here's where patience comes in... continue bubbling until the copper wire is completely dissolved. If the solution becomes a brownish, possibly muddy, color, add 1oz of hydrochloric acid and continue bubbling until the wire is completely dissolved AND the solution is a deep emerald green. The color will be fairly dark, so hold the solution up to a bright light, or pour a bit into a smaller container, to gauge the color. If the acid you're using is on the weaker side, you may need to repeat the addition of a bit (less than an ounce this time) of HCl if several days of bubbling don't result in a deep emerald green color with no trace of a brownish or muddy color.

Dilute to 1 liter with water and that's it.

Use it as you'd use any solution to etch PCBs and pour the used solution back into the main glass container when done. Inspect for color each time you pour solution into your etching tank. (It should be easier to gauge the color in the etching tank because you won't be looking thru as much solution.) As long as it's emerald green or only slightly off color, it's good. No harm in bubbling to rejuvenate after every use, but not necessary until it's no longer a pure emerald green.

The amount of excess HCl in the solution is designed to be quite low to none. If excess HCl is present there's no avoiding some of it being driven off by bubbling, but at very low concentrations that amount is essentially negligible. For those whom I might consider overly concerned... you can have the greater peace of mind you desire by avoiding unnecessary rejuvenation... and when HCl must be added because the solution won't fully rejuvenate, you can add it in smaller increments than I recommend until the solution can be rejuvenated to a pure emerald green.

At some point you'll find you can't rejuvenate just by bubbling. When that happens, add 1oz (less if highly concerned about corrosive fumes) of hydrochloric acid and bubble until emerald green. Add less than an ounce if worried about corrosive fumes, but realize you may need to add several of those smaller amounts to fully rejuvenate.

Maintain the solution level in the glass container at 1 liter - or whatever your initial volume was by adding water if it falls lower. If you only add HCl very sparingly, you can easily find the volume of the solution doesn't increase because some water evaporates when bubbling.

Over time, depending how much etching you do, copper will build up in the solution. When this occurs you can remove a bit of solution (maybe 0.5 - 1 cup), pour it into a pint jar and set it somewhere to evaporate. Make up what you remove with water. If you accumulate any significant amount of copper chloride crystals in this jar, you can scrape it into a small freezer baggie and give it to someone who wants to use it to kick start his own etching solution. Just dissolve it in water and add a small bit of HCl and you have etching solution. Add copper wire to it and bubble air thru it, adding HCl until the wire dissolves and you have stronger etching solution. A weaker solution will etch a PCB, but may undercut a bit due to the much longer time it will take.

That's it.

Jim H
 

On Sat, 23 Mar 2019 18:26:47 +0000, you wrote:

Received from Dave at 3/23/2019 04:30 PM UTC:

Thank you very much Jim. Great info and very helpful. I really appreciate
it. :-) One question though, when I look up "fritted glass bubbler" I mainly
find bongs. Where is a good place to buy a "fritted glass bubbler"??

At your local pet/aquarium store. A fritted glass bubbler will be all
glass... a glass tube with an enlarged porous end on it. Describe it like
that if they don't understand "fritted glass." You don't want a tube with a
porous ceramic stone glued onto it as the stone is liable to deteriorate in
the solution.
I can almost guarantee it will... Never had any that lasted.

If you can't get a tube with a porous glass end, just a plain
plastic tube with an open end will do, tho it will take longer to regenerate.
Shouldn't be hard to find the fritted glass bubbler in any half decent
aquarium store.
If you can't do that, then you can take some standard PVC water
tubing, just a few inches, put an adaptor on that (either plastic in
the mixture, or L the tubing outside, and U it down over the tank
wall), then drill small holes in it. If you want, you could use a
screw fitting so that "experiments" in hole size involve wasting less
material.

Never had a problem with the pipe and etchant.

I do like the idea of the glass bubbler, but I just never found any.

Harvey



Jim H



Dave

On 3/22/2019 7:50 PM, Jim Higgins wrote:

OVERVIEW:

This is a simple procedure for preparing 1 liter of cupric chloride etching
solution. The tradeoff for the simplicity is a bit of patience as it may
take a while to complete the preparation. The value of this patience is
that the resulting solution won't be overburdened with hydrochloric acid
and thus won't be as smelly and as corrosive to materials around it as more
quickly prepared solutions tend to be. It also won't have any residual
hydrogen peroxide which will result in a very slightly lower tendency to
undercut your PCB traces. That last effect is really quite small, but why
not? Also, since we won't be depending on the presence of H2O2 once the
etching solution is prepared, we don't have to worry about over diluting
our solution by trying to regenerate it with the weak 3% H2O2 commonly
available in drugstores. We'll be regenerating with an air bubbler, which
can serve double duty to agitate the solution when etching.


MATERIALS:

One large (at least 2 liter/0.5 gallon) glass container with a plastic lid.
A 1/2 gallon "iced tea" jar with a plastic lid (plastic liner or no liner)
and a small pop open spout would be ideal because you can open the spout to
insert a fritted glass bubbler for use in rejuvenating the solution after
use. If you need more than 1 liter (1 qt) of solution, consider using a
larger container and increase the amounts of materials below accordingly. I
suggest the container be only about half full when done. Only partially
full plus a small opening in the lid keeps any spray resulting from
regeneration by air bubbling inside the glass container.

One small aquarium pump. The cheap vibrating kind is fine.

One fritted glass bubbler, preferably long enough that it can reach the
bottom of the large glass container with at least an inch or more of glass
tube sticking out - preferably. If you can't find one that long, then your
plastic tubing will extend into the container. I don't like that, but
that's just me.

Plastic tubing to connect the pump to the fritted glass bubbler. I like
enough tubing that I can place my pump higher then the top of my jar. Not
likely the solution will syphon out if the pump is lower, but it's 100%
impossible if it's higher.

200 grams (7 oz) copper wire, copper pipe or other pure copper. I used
solid copper wire, but stranded copper will dissolve faster for those in a
hurry. Pennies (even the old type) and misc plumbing hardware aren't pure
copper and are unsuitable. 200 gms of copper is about 14 feet of #10 copper
wire.

Hydrochloric (muriatic) acid concrete driveway cleaner, free of detergent
or other additives. (Read the label.) This should be 32 - 37% HCl. Weaker
will work, but will require more. You can get this at Home Depot, Lowes and
assorted hardware stores. It will probably cost more at pool supply places.

Hydrogen peroxide. The typical 3% solution from the drugstore is fine. You
only need a few ounces.


SOLUTION PREPARATION:

Pour 1 liter (4-1/4 cups) of water into your container and mark the level
on the outside of the container. Pour out the water. This is the level you
will want to maintain later after etching and rejuvenating.

Add the copper to the glass container.

Place 0.6 liters (2.5 cups) of hydrochloric acid in the glass container.

Add 0.1 liter (0.5 cup) of hydrogen peroxide. This should be all the
hydrogen peroxide you'll ever need.

The copper wire will begin dissolving as evidenced by a green color forming
in the solution and bubbles being generated on the surface of the copper wire.

Place the lid on the container, open the spout and insert the fritted glass
bubbler connected to aquarium pump and begin bubbling to mix the solution.

Here's where patience comes in... continue bubbling until the copper wire
is completely dissolved. If the solution becomes a brownish, possibly
muddy, color, add 1oz of hydrochloric acid and continue bubbling until the
wire is completely dissolved AND the solution is a deep emerald green. The
color will be fairly dark, so hold the solution up to a bright light, or
pour a bit into a smaller container, to gauge the color. If the acid you're
using is on the weaker side, you may need to repeat the addition of a bit
(less than an ounce this time) of HCl if several days of bubbling don't
result in a deep emerald green color with no trace of a brownish or muddy color.

Dilute to 1 liter with water and that's it.

Use it as you'd use any solution to etch PCBs and pour the used solution
back into the main glass container when done. Inspect for color each time
you pour solution into your etching tank. (It should be easier to gauge the
color in the etching tank because you won't be looking thru as much
solution.) As long as it's emerald green or only slightly off color, it's
good. No harm in bubbling to rejuvenate after every use, but not necessary
until it's no longer a pure emerald green.

The amount of excess HCl in the solution is designed to be quite low to
none. If excess HCl is present there's no avoiding some of it being driven
off by bubbling, but at very low concentrations that amount is essentially
negligible. For those whom I might consider overly concerned... you can
have the greater peace of mind you desire by avoiding unnecessary
rejuvenation... and when HCl must be added because the solution won't fully
rejuvenate, you can add it in smaller increments than I recommend until the
solution can be rejuvenated to a pure emerald green.

At some point you'll find you can't rejuvenate just by bubbling. When that
happens, add 1oz (less if highly concerned about corrosive fumes) of
hydrochloric acid and bubble until emerald green. Add less than an ounce if
worried about corrosive fumes, but realize you may need to add several of
those smaller amounts to fully rejuvenate.

Maintain the solution level in the glass container at 1 liter - or whatever
your initial volume was by adding water if it falls lower. If you only add
HCl very sparingly, you can easily find the volume of the solution doesn't
increase because some water evaporates when bubbling.

Over time, depending how much etching you do, copper will build up in the
solution. When this occurs you can remove a bit of solution (maybe 0.5 - 1
cup), pour it into a pint jar and set it somewhere to evaporate. Make up
what you remove with water. If you accumulate any significant amount of
copper chloride crystals in this jar, you can scrape it into a small
freezer baggie and give it to someone who wants to use it to kick start his
own etching solution. Just dissolve it in water and add a small bit of HCl
and you have etching solution. Add copper wire to it and bubble air thru
it, adding HCl until the wire dissolves and you have stronger etching
solution. A weaker solution will etch a PCB, but may undercut a bit due to
the much longer time it will take.

That's it.

Jim H
 

LOL, I never heard of a "fritted gass bubbler" so I googled and one of the first "hits" ,pun intended.was this:
https://www.youtube.com/watch?v=DQOBdtsKqaQ
 

开云体育

Also called scintered glass.? Look for CO2 infusors used in pkanted aquariums.

IMO, smaller bubbles meam more aerosolization if the etchant.? As I've said, the aerosol us very corrosive.? You almost need two containments, one for luquid, anither for the gasses.

Rubber gloves and swabs do as well, IMO.



Sent from my T-Mobile 4G LTE Tablet

-------- Original message --------
From: Harvey White <madyn@...>
Date: 3/23/19 2:11 PM (GMT-06:00)
Subject: Re: [homebrewpcbs] Preparing Cupric Chloride Etching Solution

On Sat, 23 Mar 2019 18:26:47 +0000, you wrote:

>Received from Dave at 3/23/2019 04:30 PM UTC:
>
>>Thank you very much Jim. Great info and very helpful. I really appreciate
>>it. :-) One question though, when I look up "fritted glass bubbler" I mainly
>>find bongs. Where is a good place to buy a "fritted glass bubbler"??
>
>
>At your local pet/aquarium store. A fritted glass bubbler will be all
>glass... a glass tube with an enlarged porous end on it. Describe it like
>that if they don't understand "fritted glass." You don't want a tube with a
>porous ceramic stone glued onto it as the stone is liable to deteriorate in
>the solution.

I can almost guarantee it will... Never had any that lasted.

>If you can't get a tube with a porous glass end, just a plain
>plastic tube with an open end will do, tho it will take longer to regenerate.
>Shouldn't be hard to find the fritted glass bubbler in any half decent
>aquarium store.

If you can't do that, then you can take some standard PVC water
tubing, just a few inches, put an adaptor on that (either plastic in
the mixture, or L the tubing outside, and U it down over the tank
wall), then drill small holes in it.? If you want, you could use a
screw fitting so that "experiments" in hole size involve wasting less
material.

Never had a problem with the pipe and etchant.

I do like the idea of the glass bubbler, but I just never found any.

Harvey


>
>Jim H
>
>
>
>>Dave
>>
>>On 3/22/2019 7:50 PM, Jim Higgins wrote:
>>>
>>>OVERVIEW:
>>>
>>>This is a simple procedure for preparing 1 liter of cupric chloride etching
>>>solution. The tradeoff for the simplicity is a bit of patience as it may
>>>take a while to complete the preparation. The value of this patience is
>>>that the resulting solution won't be overburdened with hydrochloric acid
>>>and thus won't be as smelly and as corrosive to materials around it as more
>>>quickly prepared solutions tend to be. It also won't have any residual
>>>hydrogen peroxide which will result in a very slightly lower tendency to
>>>undercut your PCB traces. That last effect is really quite small, but why
>>>not? Also, since we won't be depending on the presence of H2O2 once the
>>>etching solution is prepared, we don't have to worry about over diluting
>>>our solution by trying to regenerate it with the weak 3% H2O2 commonly
>>>available in drugstores. We'll be regenerating with an air bubbler, which
>>>can serve double duty to agitate the solution when etching.
>>>
>>>
>>>MATERIALS:
>>>
>>>One large (at least 2 liter/0.5 gallon) glass container with a plastic lid.
>>>A 1/2 gallon "iced tea" jar with a plastic lid (plastic liner or no liner)
>>>and a small pop open spout would be ideal because you can open the spout to
>>>insert a fritted glass bubbler for use in rejuvenating the solution after
>>>use. If you need more than 1 liter (1 qt) of solution, consider using a
>>>larger container and increase the amounts of materials below accordingly. I
>>>suggest the container be only about half full when done. Only partially
>>>full plus a small opening in the lid keeps any spray resulting from
>>>regeneration by air bubbling inside the glass container.
>>>
>>>One small aquarium pump. The cheap vibrating kind is fine.
>>>
>>>One fritted glass bubbler, preferably long enough that it can reach the
>>>bottom of the large glass container with at least an inch or more of glass
>>>tube sticking out - preferably. If you can't find one that long, then your
>>>plastic tubing will extend into the container. I don't like that, but
>>>that's just me.
>>>
>>>Plastic tubing to connect the pump to the fritted glass bubbler. I like
>>>enough tubing that I can place my pump higher then the top of my jar. Not
>>>likely the solution will syphon out if the pump is lower, but it's 100%
>>>impossible if it's higher.
>>>
>>>200 grams (7 oz) copper wire, copper pipe or other pure copper. I used
>>>solid copper wire, but stranded copper will dissolve faster for those in a
>>>hurry. Pennies (even the old type) and misc plumbing hardware aren't pure
>>>copper and are unsuitable. 200 gms of copper is about 14 feet of #10 copper
>>>wire.
>>>
>>>Hydrochloric (muriatic) acid concrete driveway cleaner, free of detergent
>>>or other additives. (Read the label.) This should be 32 - 37% HCl. Weaker
>>>will work, but will require more. You can get this at Home Depot, Lowes and
>>>assorted hardware stores. It will probably cost more at pool supply places.
>>>
>>>Hydrogen peroxide. The typical 3% solution from the drugstore is fine. You
>>>only need a few ounces.
>>>
>>>
>>>SOLUTION PREPARATION:
>>>
>>>Pour 1 liter (4-1/4 cups) of water into your container and mark the level
>>>on the outside of the container. Pour out the water. This is the level you
>>>will want to maintain later after etching and rejuvenating.
>>>
>>>Add the copper to the glass container.
>>>
>>>Place 0.6 liters (2.5 cups) of hydrochloric acid in the glass container.
>>>
>>>Add 0.1 liter (0.5 cup) of hydrogen peroxide. This should be all the
>>>hydrogen peroxide you'll ever need.
>>>
>>>The copper wire will begin dissolving as evidenced by a green color forming
>>>in the solution and bubbles being generated on the surface of the copper wire.
>>>
>>>Place the lid on the container, open the spout and insert the fritted glass
>>>bubbler connected to aquarium pump and begin bubbling to mix the solution.
>>>
>>>Here's where patience comes in... continue bubbling until the copper wire
>>>is completely dissolved. If the solution becomes a brownish, possibly
>>>muddy, color, add 1oz of hydrochloric acid and continue bubbling until the
>>>wire is completely dissolved AND the solution is a deep emerald green. The
>>>color will be fairly dark, so hold the solution up to a bright light, or
>>>pour a bit into a smaller container, to gauge the color. If the acid you're
>>>using is on the weaker side, you may need to repeat the addition of a bit
>>>(less than an ounce this time) of HCl if several days of bubbling don't
>>>result in a deep emerald green color with no trace of a brownish or muddy color.
>>>
>>>Dilute to 1 liter with water and that's it.
>>>
>>>Use it as you'd use any solution to etch PCBs and pour the used solution
>>>back into the main glass container when done. Inspect for color each time
>>>you pour solution into your etching tank. (It should be easier to gauge the
>>>color in the etching tank because you won't be looking thru as much
>>>solution.) As long as it's emerald green or only slightly off color, it's
>>>good. No harm in bubbling to rejuvenate after every use, but not necessary
>>>until it's no longer a pure emerald green.
>>>
>>>The amount of excess HCl in the solution is designed to be quite low to
>>>none. If excess HCl is present there's no avoiding some of it being driven
>>>off by bubbling, but at very low concentrations that amount is essentially
>>>negligible. For those whom I might consider overly concerned... you can
>>>have the greater peace of mind you desire by avoiding unnecessary
>>>rejuvenation... and when HCl must be added because the solution won't fully
>>>rejuvenate, you can add it in smaller increments than I recommend until the
>>>solution can be rejuvenated to a pure emerald green.
>>>
>>>At some point you'll find you can't rejuvenate just by bubbling. When that
>>>happens, add 1oz (less if highly concerned about corrosive fumes) of
>>>hydrochloric acid and bubble until emerald green. Add less than an ounce if
>>>worried about corrosive fumes, but realize you may need to add several of
>>>those smaller amounts to fully rejuvenate.
>>>
>>>Maintain the solution level in the glass container at 1 liter - or whatever
>>>your initial volume was by adding water if it falls lower. If you only add
>>>HCl very sparingly, you can easily find the volume of the solution doesn't
>>>increase because some water evaporates when bubbling.
>>>
>>>Over time, depending how much etching you do, copper will build up in the
>>>solution. When this occurs you can remove a bit of solution (maybe 0.5 - 1
>>>cup), pour it into a pint jar and set it somewhere to evaporate. Make up
>>>what you remove with water. If you accumulate any significant amount of
>>>copper chloride crystals in this jar, you can scrape it into a small
>>>freezer baggie and give it to someone who wants to use it to kick start his
>>>own etching solution. Just dissolve it in water and add a small bit of HCl
>>>and you have etching solution. Add copper wire to it and bubble air thru
>>>it, adding HCl until the wire dissolves and you have stronger etching
>>>solution. A weaker solution will etch a PCB, but may undercut a bit due to
>>>the much longer time it will take.
>>>
>>>That's it.
>>>
>>>Jim H
>>>
>>>
>>
>>
>>
>
>
>
>
 

开云体育

https://smile.amazon.com/JARDLI-Diffuser-Counter-Aquarium-Planted/dp/B01N36MAO4/ref=sr_1_1_sspa?keywords=co2+sintered+glass&qid=1553378698&s=gateway&sr=8-1-spons&psc=1

Consider something like this:?https://smile.amazon.com/Homasy-Submersible-Aquarium-Fountain-Powerful/dp/B00EWENMAU/ref=sr_1_4?keywords=submersible+water+pump&qid=1553378827&s=gateway&sr=8-4


Sent from my T-Mobile 4G LTE Tablet

-------- Original message --------
From: Lee Studley <indigoredster@...>
Date: 3/23/19 4:52 PM (GMT-06:00)
Subject: Re: [homebrewpcbs] Preparing Cupric Chloride Etching Solution

LOL, I never heard of a "fritted gass bubbler" so I googled and one of the first "hits" ,pun intended.was this:
https://www.youtube.com/watch?v=DQOBdtsKqaQ

 

Hi Jim,

? Ok, I will see if the local shops know of them. I already found them under "gas dispersion tubes" too online but those scientific ones are pricey. Iam sure I will hunt one down...

Thanks,

Dave

On 3/23/2019 1:26 PM, Jim Higgins wrote:
Received from Dave at 3/23/2019 04:30 PM UTC:

Thank you very much Jim. Great info and very helpful. I really appreciate it. :-) One question though, when I look up "fritted glass bubbler" I mainly find bongs. Where is a good place to buy a "fritted glass bubbler"??

At your local pet/aquarium store. A fritted glass bubbler will be all glass... a glass tube with an enlarged porous end on it. Describe it like that if they don't understand "fritted glass." You don't want a tube with a porous ceramic stone glued onto it as the stone is liable to deteriorate in the solution. If you can't get a tube with a porous glass end, just a plain plastic tube with an open end will do, tho it will take longer to regenerate. Shouldn't be hard to find the fritted glass bubbler in any half decent aquarium store.

Jim H



Dave

On 3/22/2019 7:50 PM, Jim Higgins wrote:

OVERVIEW:

This is a simple procedure for preparing 1 liter of cupric chloride etching solution. The tradeoff for the simplicity is a bit of patience as it may take a while to complete the preparation. The value of this patience is that the resulting solution won't be overburdened with hydrochloric acid and thus won't be as smelly and as corrosive to materials around it as more quickly prepared solutions tend to be. It also won't have any residual hydrogen peroxide which will result in a very slightly lower tendency to undercut your PCB traces. That last effect is really quite small, but why not? Also, since we won't be depending on the presence of H2O2 once the etching solution is prepared, we don't have to worry about over diluting our solution by trying to regenerate it with the weak 3% H2O2 commonly available in drugstores. We'll be regenerating with an air bubbler, which can serve double duty to agitate the solution when etching.


MATERIALS:

One large (at least 2 liter/0.5 gallon) glass container with a plastic lid. A 1/2 gallon "iced tea" jar with a plastic lid (plastic liner or no liner) and a small pop open spout would be ideal because you can open the spout to insert a fritted glass bubbler for use in rejuvenating the solution after use. If you need more than 1 liter (1 qt) of solution, consider using a larger container and increase the amounts of materials below accordingly. I suggest the container be only about half full when done. Only partially full plus a small opening in the lid keeps any spray resulting from regeneration by air bubbling inside the glass container.

One small aquarium pump. The cheap vibrating kind is fine.

One fritted glass bubbler, preferably long enough that it can reach the bottom of the large glass container with at least an inch or more of glass tube sticking out - preferably. If you can't find one that long, then your plastic tubing will extend into the container. I don't like that, but that's just me.

Plastic tubing to connect the pump to the fritted glass bubbler. I like enough tubing that I can place my pump higher then the top of my jar. Not likely the solution will syphon out if the pump is lower, but it's 100% impossible if it's higher.

200 grams (7 oz) copper wire, copper pipe or other pure copper. I used solid copper wire, but stranded copper will dissolve faster for those in a hurry. Pennies (even the old type) and misc plumbing hardware aren't pure copper and are unsuitable. 200 gms of copper is about 14 feet of #10 copper wire.

Hydrochloric (muriatic) acid concrete driveway cleaner, free of detergent or other additives. (Read the label.) This should be 32 - 37% HCl. Weaker will work, but will require more. You can get this at Home Depot, Lowes and assorted hardware stores. It will probably cost more at pool supply places.

Hydrogen peroxide. The typical 3% solution from the drugstore is fine. You only need a few ounces.


SOLUTION PREPARATION:

Pour 1 liter (4-1/4 cups) of water into your container and mark the level on the outside of the container. Pour out the water. This is the level you will want to maintain later after etching and rejuvenating.

Add the copper to the glass container.

Place 0.6 liters (2.5 cups) of hydrochloric acid in the glass container.

Add 0.1 liter (0.5 cup) of hydrogen peroxide. This should be all the hydrogen peroxide you'll ever need.

The copper wire will begin dissolving as evidenced by a green color forming in the solution and bubbles being generated on the surface of the copper wire.

Place the lid on the container, open the spout and insert the fritted glass bubbler connected to aquarium pump and begin bubbling to mix the solution.

Here's where patience comes in... continue bubbling until the copper wire is completely dissolved. If the solution becomes a brownish, possibly muddy, color, add 1oz of hydrochloric acid and continue bubbling until the wire is completely dissolved AND the solution is a deep emerald green. The color will be fairly dark, so hold the solution up to a bright light, or pour a bit into a smaller container, to gauge the color. If the acid you're using is on the weaker side, you may need to repeat the addition of a bit (less than an ounce this time) of HCl if several days of bubbling don't result in a deep emerald green color with no trace of a brownish or muddy color.

Dilute to 1 liter with water and that's it.

Use it as you'd use any solution to etch PCBs and pour the used solution back into the main glass container when done. Inspect for color each time you pour solution into your etching tank. (It should be easier to gauge the color in the etching tank because you won't be looking thru as much solution.) As long as it's emerald green or only slightly off color, it's good. No harm in bubbling to rejuvenate after every use, but not necessary until it's no longer a pure emerald green.

The amount of excess HCl in the solution is designed to be quite low to none. If excess HCl is present there's no avoiding some of it being driven off by bubbling, but at very low concentrations that amount is essentially negligible. For those whom I might consider overly concerned... you can have the greater peace of mind you desire by avoiding unnecessary rejuvenation... and when HCl must be added because the solution won't fully rejuvenate, you can add it in smaller increments than I recommend until the solution can be rejuvenated to a pure emerald green.

At some point you'll find you can't rejuvenate just by bubbling. When that happens, add 1oz (less if highly concerned about corrosive fumes) of hydrochloric acid and bubble until emerald green. Add less than an ounce if worried about corrosive fumes, but realize you may need to add several of those smaller amounts to fully rejuvenate.

Maintain the solution level in the glass container at 1 liter - or whatever your initial volume was by adding water if it falls lower. If you only add HCl very sparingly, you can easily find the volume of the solution doesn't increase because some water evaporates when bubbling.

Over time, depending how much etching you do, copper will build up in the solution. When this occurs you can remove a bit of solution (maybe 0.5 - 1 cup), pour it into a pint jar and set it somewhere to evaporate. Make up what you remove with water. If you accumulate any significant amount of copper chloride crystals in this jar, you can scrape it into a small freezer baggie and give it to someone who wants to use it to kick start his own etching solution. Just dissolve it in water and add a small bit of HCl and you have etching solution. Add copper wire to it and bubble air thru it, adding HCl until the wire dissolves and you have stronger etching solution. A weaker solution will etch a PCB, but may undercut a bit due to the much longer time it will take.

That's it.

Jim H
 

On 3/23/2019 2:11 PM, Harvey White wrote:
On Sat, 23 Mar 2019 18:26:47 +0000, you wrote:

Received from Dave at 3/23/2019 04:30 PM UTC:

Thank you very much Jim. Great info and very helpful. I really appreciate
it. :-) One question though, when I look up "fritted glass bubbler" I mainly
find bongs. Where is a good place to buy a "fritted glass bubbler"??
At your local pet/aquarium store. A fritted glass bubbler will be all
glass... a glass tube with an enlarged porous end on it. Describe it like
that if they don't understand "fritted glass." You don't want a tube with a
porous ceramic stone glued onto it as the stone is liable to deteriorate in
the solution.
I can almost guarantee it will... Never had any that lasted.
??? ??? That is what I heard so I want to avoid problems of any kind.

If you can't get a tube with a porous glass end, just a plain
plastic tube with an open end will do, tho it will take longer to regenerate.
Shouldn't be hard to find the fritted glass bubbler in any half decent
aquarium store.
If you can't do that, then you can take some standard PVC water
tubing, just a few inches, put an adaptor on that (either plastic in
the mixture, or L the tubing outside, and U it down over the tank
wall), then drill small holes in it. If you want, you could use a
screw fitting so that "experiments" in hole size involve wasting less
material.

Never had a problem with the pipe and etchant.

I do like the idea of the glass bubbler, but I just never found any.

??? ??? Plastic tube will work and it's easy enough to drill holes in it. But can't we drill holes in glass tubes with our carbide bits?? Or would we break more of them than its worth? If a person were to try that, what size carbide would be strong enough without being excessive in size I wonder?


Harvey


Jim H



Dave

On 3/22/2019 7:50 PM, Jim Higgins wrote:
OVERVIEW:

This is a simple procedure for preparing 1 liter of cupric chloride etching
solution. The tradeoff for the simplicity is a bit of patience as it may
take a while to complete the preparation. The value of this patience is
that the resulting solution won't be overburdened with hydrochloric acid
and thus won't be as smelly and as corrosive to materials around it as more
quickly prepared solutions tend to be. It also won't have any residual
hydrogen peroxide which will result in a very slightly lower tendency to
undercut your PCB traces. That last effect is really quite small, but why
not? Also, since we won't be depending on the presence of H2O2 once the
etching solution is prepared, we don't have to worry about over diluting
our solution by trying to regenerate it with the weak 3% H2O2 commonly
available in drugstores. We'll be regenerating with an air bubbler, which
can serve double duty to agitate the solution when etching.


MATERIALS:

One large (at least 2 liter/0.5 gallon) glass container with a plastic lid.
A 1/2 gallon "iced tea" jar with a plastic lid (plastic liner or no liner)
and a small pop open spout would be ideal because you can open the spout to
insert a fritted glass bubbler for use in rejuvenating the solution after
use. If you need more than 1 liter (1 qt) of solution, consider using a
larger container and increase the amounts of materials below accordingly. I
suggest the container be only about half full when done. Only partially
full plus a small opening in the lid keeps any spray resulting from
regeneration by air bubbling inside the glass container.

One small aquarium pump. The cheap vibrating kind is fine.

One fritted glass bubbler, preferably long enough that it can reach the
bottom of the large glass container with at least an inch or more of glass
tube sticking out - preferably. If you can't find one that long, then your
plastic tubing will extend into the container. I don't like that, but
that's just me.

Plastic tubing to connect the pump to the fritted glass bubbler. I like
enough tubing that I can place my pump higher then the top of my jar. Not
likely the solution will syphon out if the pump is lower, but it's 100%
impossible if it's higher.

200 grams (7 oz) copper wire, copper pipe or other pure copper. I used
solid copper wire, but stranded copper will dissolve faster for those in a
hurry. Pennies (even the old type) and misc plumbing hardware aren't pure
copper and are unsuitable. 200 gms of copper is about 14 feet of #10 copper
wire.

Hydrochloric (muriatic) acid concrete driveway cleaner, free of detergent
or other additives. (Read the label.) This should be 32 - 37% HCl. Weaker
will work, but will require more. You can get this at Home Depot, Lowes and
assorted hardware stores. It will probably cost more at pool supply places.

Hydrogen peroxide. The typical 3% solution from the drugstore is fine. You
only need a few ounces.


SOLUTION PREPARATION:

Pour 1 liter (4-1/4 cups) of water into your container and mark the level
on the outside of the container. Pour out the water. This is the level you
will want to maintain later after etching and rejuvenating.

Add the copper to the glass container.

Place 0.6 liters (2.5 cups) of hydrochloric acid in the glass container.

Add 0.1 liter (0.5 cup) of hydrogen peroxide. This should be all the
hydrogen peroxide you'll ever need.

The copper wire will begin dissolving as evidenced by a green color forming
in the solution and bubbles being generated on the surface of the copper wire.

Place the lid on the container, open the spout and insert the fritted glass
bubbler connected to aquarium pump and begin bubbling to mix the solution.

Here's where patience comes in... continue bubbling until the copper wire
is completely dissolved. If the solution becomes a brownish, possibly
muddy, color, add 1oz of hydrochloric acid and continue bubbling until the
wire is completely dissolved AND the solution is a deep emerald green. The
color will be fairly dark, so hold the solution up to a bright light, or
pour a bit into a smaller container, to gauge the color. If the acid you're
using is on the weaker side, you may need to repeat the addition of a bit
(less than an ounce this time) of HCl if several days of bubbling don't
result in a deep emerald green color with no trace of a brownish or muddy color.

Dilute to 1 liter with water and that's it.

Use it as you'd use any solution to etch PCBs and pour the used solution
back into the main glass container when done. Inspect for color each time
you pour solution into your etching tank. (It should be easier to gauge the
color in the etching tank because you won't be looking thru as much
solution.) As long as it's emerald green or only slightly off color, it's
good. No harm in bubbling to rejuvenate after every use, but not necessary
until it's no longer a pure emerald green.

The amount of excess HCl in the solution is designed to be quite low to
none. If excess HCl is present there's no avoiding some of it being driven
off by bubbling, but at very low concentrations that amount is essentially
negligible. For those whom I might consider overly concerned... you can
have the greater peace of mind you desire by avoiding unnecessary
rejuvenation... and when HCl must be added because the solution won't fully
rejuvenate, you can add it in smaller increments than I recommend until the
solution can be rejuvenated to a pure emerald green.

At some point you'll find you can't rejuvenate just by bubbling. When that
happens, add 1oz (less if highly concerned about corrosive fumes) of
hydrochloric acid and bubble until emerald green. Add less than an ounce if
worried about corrosive fumes, but realize you may need to add several of
those smaller amounts to fully rejuvenate.

Maintain the solution level in the glass container at 1 liter - or whatever
your initial volume was by adding water if it falls lower. If you only add
HCl very sparingly, you can easily find the volume of the solution doesn't
increase because some water evaporates when bubbling.

Over time, depending how much etching you do, copper will build up in the
solution. When this occurs you can remove a bit of solution (maybe 0.5 - 1
cup), pour it into a pint jar and set it somewhere to evaporate. Make up
what you remove with water. If you accumulate any significant amount of
copper chloride crystals in this jar, you can scrape it into a small
freezer baggie and give it to someone who wants to use it to kick start his
own etching solution. Just dissolve it in water and add a small bit of HCl
and you have etching solution. Add copper wire to it and bubble air thru
it, adding HCl until the wire dissolves and you have stronger etching
solution. A weaker solution will etch a PCB, but may undercut a bit due to
the much longer time it will take.

That's it.

Jim H
 

开云体育

Dale,

? Thanks for the added info.

On 3/23/2019 5:02 PM, dale.chatham wrote:

Also called scintered glass.? Look for CO2 infusors used in pkanted aquariums.

IMO, smaller bubbles meam more aerosolization if the etchant.? As I've said, the aerosol us very corrosive.? You almost need two containments, one for luquid, anither for the gasses.

Rubber gloves and swabs do as well, IMO.



Sent from my T-Mobile 4G LTE Tablet

-------- Original message --------
From: Harvey White <madyn@...>
Date: 3/23/19 2:11 PM (GMT-06:00)
Subject: Re: [homebrewpcbs] Preparing Cupric Chloride Etching Solution

On Sat, 23 Mar 2019 18:26:47 +0000, you wrote:

>Received from Dave at 3/23/2019 04:30 PM UTC:
>
>>Thank you very much Jim. Great info and very helpful. I really appreciate
>>it. :-) One question though, when I look up "fritted glass bubbler" I mainly
>>find bongs. Where is a good place to buy a "fritted glass bubbler"??
>
>
>At your local pet/aquarium store. A fritted glass bubbler will be all
>glass... a glass tube with an enlarged porous end on it. Describe it like
>that if they don't understand "fritted glass." You don't want a tube with a
>porous ceramic stone glued onto it as the stone is liable to deteriorate in
>the solution.

 

开云体育

Dale,

? That first link looks like what we are looking for. The second link though I don't think we would want to put a submersible pump in the etchant though. I am sure it has some metal parts??

On 3/23/2019 5:08 PM, dale.chatham wrote:


Consider something like this:?


Sent from my T-Mobile 4G LTE Tablet

-------- Original message --------
From: Lee Studley <indigoredster@...>
Date: 3/23/19 4:52 PM (GMT-06:00)
Subject: Re: [homebrewpcbs] Preparing Cupric Chloride Etching Solution

LOL, I never heard of a "fritted gass bubbler" so I googled and one of the first "hits" ,pun intended.was this:
 

开云体育

Submersible pumpw have a sealed motor area.? The impeller is in a separate area, with a nagnet on the motor and another on the impeller.? They are salt water safe.? Over time, salt water is very corrosive and the products of corrosion kill fish.



Sent from my T-Mobile 4G LTE Tablet

-------- Original message --------
From: Dave <theschemer@...>
Date: 3/23/19 6:48 PM (GMT-06:00)
Subject: Re: [homebrewpcbs] Preparing Cupric Chloride Etching Solution

Dale,

? That first link looks like what we are looking for. The second link though I don't think we would want to put a submersible pump in the etchant though. I am sure it has some metal parts??

On 3/23/2019 5:08 PM, dale.chatham wrote:

Consider something like this:?


Sent from my T-Mobile 4G LTE Tablet

-------- Original message --------
From: Lee Studley <indigoredster@...>
Date: 3/23/19 4:52 PM (GMT-06:00)
Subject: Re: [homebrewpcbs] Preparing Cupric Chloride Etching Solution

LOL, I never heard of a "fritted gass bubbler" so I googled and one of the first "hits" ,pun intended.was this:
 

On Sat, 23 Mar 2019 18:41:04 -0500, you wrote:


On 3/23/2019 2:11 PM, Harvey White wrote:
On Sat, 23 Mar 2019 18:26:47 +0000, you wrote:

Received from Dave at 3/23/2019 04:30 PM UTC:

Thank you very much Jim. Great info and very helpful. I really appreciate
it. :-) One question though, when I look up "fritted glass bubbler" I mainly
find bongs. Where is a good place to buy a "fritted glass bubbler"??
At your local pet/aquarium store. A fritted glass bubbler will be all
glass... a glass tube with an enlarged porous end on it. Describe it like
that if they don't understand "fritted glass." You don't want a tube with a
porous ceramic stone glued onto it as the stone is liable to deteriorate in
the solution.
I can almost guarantee it will... Never had any that lasted.
??? ??? That is what I heard so I want to avoid problems of any kind.
Exactly.

If you can't get a tube with a porous glass end, just a plain
plastic tube with an open end will do, tho it will take longer to regenerate.
Shouldn't be hard to find the fritted glass bubbler in any half decent
aquarium store.
If you can't do that, then you can take some standard PVC water
tubing, just a few inches, put an adaptor on that (either plastic in
the mixture, or L the tubing outside, and U it down over the tank
wall), then drill small holes in it. If you want, you could use a
screw fitting so that "experiments" in hole size involve wasting less
material.

Never had a problem with the pipe and etchant.

I do like the idea of the glass bubbler, but I just never found any.

??? ??? Plastic tube will work and it's easy enough to drill holes in
it. But can't we drill holes in glass tubes with our carbide bits?? Or
would we break more of them than its worth? If a person were to try
that, what size carbide would be strong enough without being excessive
in size I wonder?
Actually, it may not be all that easy to drill a hole in a glass tube.
Considering that the PVC pipe works, is dirt cheap, and won't break
under too much pressure (and can be drilled with standard drills....),
I'm wondering why to go through the problems of drilling glass....

Seriously enough, you'll lose perhaps an inch in the bottom of the
tank, and if you put a grille made from fluorescent light grids, you
may miss a bit more.

Then again, those cereal storage containers are fairly deep unless you
want to do 9 or 10 inch boards (including border?) in the tank.

Harvey



Harvey


Jim H



Dave

On 3/22/2019 7:50 PM, Jim Higgins wrote:
OVERVIEW:

This is a simple procedure for preparing 1 liter of cupric chloride etching
solution. The tradeoff for the simplicity is a bit of patience as it may
take a while to complete the preparation. The value of this patience is
that the resulting solution won't be overburdened with hydrochloric acid
and thus won't be as smelly and as corrosive to materials around it as more
quickly prepared solutions tend to be. It also won't have any residual
hydrogen peroxide which will result in a very slightly lower tendency to
undercut your PCB traces. That last effect is really quite small, but why
not? Also, since we won't be depending on the presence of H2O2 once the
etching solution is prepared, we don't have to worry about over diluting
our solution by trying to regenerate it with the weak 3% H2O2 commonly
available in drugstores. We'll be regenerating with an air bubbler, which
can serve double duty to agitate the solution when etching.


MATERIALS:

One large (at least 2 liter/0.5 gallon) glass container with a plastic lid.
A 1/2 gallon "iced tea" jar with a plastic lid (plastic liner or no liner)
and a small pop open spout would be ideal because you can open the spout to
insert a fritted glass bubbler for use in rejuvenating the solution after
use. If you need more than 1 liter (1 qt) of solution, consider using a
larger container and increase the amounts of materials below accordingly. I
suggest the container be only about half full when done. Only partially
full plus a small opening in the lid keeps any spray resulting from
regeneration by air bubbling inside the glass container.

One small aquarium pump. The cheap vibrating kind is fine.

One fritted glass bubbler, preferably long enough that it can reach the
bottom of the large glass container with at least an inch or more of glass
tube sticking out - preferably. If you can't find one that long, then your
plastic tubing will extend into the container. I don't like that, but
that's just me.

Plastic tubing to connect the pump to the fritted glass bubbler. I like
enough tubing that I can place my pump higher then the top of my jar. Not
likely the solution will syphon out if the pump is lower, but it's 100%
impossible if it's higher.

200 grams (7 oz) copper wire, copper pipe or other pure copper. I used
solid copper wire, but stranded copper will dissolve faster for those in a
hurry. Pennies (even the old type) and misc plumbing hardware aren't pure
copper and are unsuitable. 200 gms of copper is about 14 feet of #10 copper
wire.

Hydrochloric (muriatic) acid concrete driveway cleaner, free of detergent
or other additives. (Read the label.) This should be 32 - 37% HCl. Weaker
will work, but will require more. You can get this at Home Depot, Lowes and
assorted hardware stores. It will probably cost more at pool supply places.

Hydrogen peroxide. The typical 3% solution from the drugstore is fine. You
only need a few ounces.


SOLUTION PREPARATION:

Pour 1 liter (4-1/4 cups) of water into your container and mark the level
on the outside of the container. Pour out the water. This is the level you
will want to maintain later after etching and rejuvenating.

Add the copper to the glass container.

Place 0.6 liters (2.5 cups) of hydrochloric acid in the glass container.

Add 0.1 liter (0.5 cup) of hydrogen peroxide. This should be all the
hydrogen peroxide you'll ever need.

The copper wire will begin dissolving as evidenced by a green color forming
in the solution and bubbles being generated on the surface of the copper wire.

Place the lid on the container, open the spout and insert the fritted glass
bubbler connected to aquarium pump and begin bubbling to mix the solution.

Here's where patience comes in... continue bubbling until the copper wire
is completely dissolved. If the solution becomes a brownish, possibly
muddy, color, add 1oz of hydrochloric acid and continue bubbling until the
wire is completely dissolved AND the solution is a deep emerald green. The
color will be fairly dark, so hold the solution up to a bright light, or
pour a bit into a smaller container, to gauge the color. If the acid you're
using is on the weaker side, you may need to repeat the addition of a bit
(less than an ounce this time) of HCl if several days of bubbling don't
result in a deep emerald green color with no trace of a brownish or muddy color.

Dilute to 1 liter with water and that's it.

Use it as you'd use any solution to etch PCBs and pour the used solution
back into the main glass container when done. Inspect for color each time
you pour solution into your etching tank. (It should be easier to gauge the
color in the etching tank because you won't be looking thru as much
solution.) As long as it's emerald green or only slightly off color, it's
good. No harm in bubbling to rejuvenate after every use, but not necessary
until it's no longer a pure emerald green.

The amount of excess HCl in the solution is designed to be quite low to
none. If excess HCl is present there's no avoiding some of it being driven
off by bubbling, but at very low concentrations that amount is essentially
negligible. For those whom I might consider overly concerned... you can
have the greater peace of mind you desire by avoiding unnecessary
rejuvenation... and when HCl must be added because the solution won't fully
rejuvenate, you can add it in smaller increments than I recommend until the
solution can be rejuvenated to a pure emerald green.

At some point you'll find you can't rejuvenate just by bubbling. When that
happens, add 1oz (less if highly concerned about corrosive fumes) of
hydrochloric acid and bubble until emerald green. Add less than an ounce if
worried about corrosive fumes, but realize you may need to add several of
those smaller amounts to fully rejuvenate.

Maintain the solution level in the glass container at 1 liter - or whatever
your initial volume was by adding water if it falls lower. If you only add
HCl very sparingly, you can easily find the volume of the solution doesn't
increase because some water evaporates when bubbling.

Over time, depending how much etching you do, copper will build up in the
solution. When this occurs you can remove a bit of solution (maybe 0.5 - 1
cup), pour it into a pint jar and set it somewhere to evaporate. Make up
what you remove with water. If you accumulate any significant amount of
copper chloride crystals in this jar, you can scrape it into a small
freezer baggie and give it to someone who wants to use it to kick start his
own etching solution. Just dissolve it in water and add a small bit of HCl
and you have etching solution. Add copper wire to it and bubble air thru
it, adding HCl until the wire dissolves and you have stronger etching
solution. A weaker solution will etch a PCB, but may undercut a bit due to
the much longer time it will take.

That's it.

Jim H
 

开云体育

Ok, good to know. Thanks for the followup. I don't think it will fit in the etchant tank I am going to build though. But still good info.

Thanks

On 3/23/2019 6:55 PM, dale.chatham wrote:

Submersible pumpw have a sealed motor area.? The impeller is in a separate area, with a nagnet on the motor and another on the impeller.? They are salt water safe.? Over time, salt water is very corrosive and the products of corrosion kill fish.



Sent from my T-Mobile 4G LTE Tablet

-------- Original message --------
From: Dave <theschemer@...>
Date: 3/23/19 6:48 PM (GMT-06:00)
Subject: Re: [homebrewpcbs] Preparing Cupric Chloride Etching Solution

Dale,

? That first link looks like what we are looking for. The second link though I don't think we would want to put a submersible pump in the etchant though. I am sure it has some metal parts??

On 3/23/2019 5:08 PM, dale.chatham wrote:

Consider something like this:?
 

Actually in "chemistry lab terminology"? they are called fretted glass filters.? Generally, they are 1-3" dia funnel sort of like devices with a fretted glass disk down near the bottom.? For filtering I assume they are available with various pore sizes, they will also work for generating very small bubbles.
Jim Higgins
 

LOL indeed!

That thing looks like a converted piece of labware. If purchased from a commercial labware company the unconverted equipment would run (semi-wild guess) maybe $600. A straight glass tube 1/4" or so in diameter with a little finger tip sized fritted end could run close to $300.

As I said earlier, I got my tube with fritted glass end at an aquarium store in PA 30 years ago for a few bucks. It cost more than the same tube with a porous stone on it, but I figured the stone or the cement holding it on wouldn't hold up and someone here confirmed that concern from personal experience.

Jim H



Received from Lee Studley at 3/23/2019 09:52 PM UTC:

LOL, I never heard of a "fritted gass bubbler" so I googled and one of the first "hits" ,pun intended.was this:
Jim Higgins
 

Received from dale.chatham at 3/23/2019 10:08 PM UTC:


This would be GREAT provided the pressure needed to make a decent amount of bubbles can be supplied by a simple vibratory fish tank air pump. Since this is being touted by the supplier as something to use in a pressurized CO2 infusion system and since it's designed to let you count bubbles of gas (below the fritted membrane) one at a time, I bet it needs a higher pressure to operate than a fish tank pump can provide, or else it will probably produce far fewer bubbles than expected/wanted to rejuvenate cupric chloride solutions.


Consider something like this:

Looks like that pump has a sealed impeller housing with no shafts or bearings that might leak. Probably worth a try for anyone who wants to agitate by pumping liquid vs injecting bubbles. Hard to tell if there are any exposed metal parts, but wouldn't expect there to be in an aquarium pump. I believe I'd put this pump in an empty bucket in case it does leak, though.

Jim H
Jim Higgins
 

all scientific stuff is incredibly pricey! If I were back in a lab, I'd guess the tube I described could cost close to $300 from a lab supply house.

And searching extensively... I can't find anything but stones bubblers when it comes to aquarium suppliers these days. And my guess that those would disintegrate was confirmed by someone's actual experience, so I'd avoid those. I see now I should have looked before assuming aquarium stores carry the same things today as the one I bought my tube in 30 years ago.

Since we're PCB making types, I'd guess we all have small enough drills to put some holes in a rigid plastic tube so it puts out fairly small bubbles... as someone else already suggested. No doubt that will get the job done, tho more slowly. Then again, we only need to etch occasionally so maybe just use a straight piece of tubing that reaches the bottom of the container. What's the rush when it comes to regeneration? None here since I haven't etched anything in maybe 6 months.

Jim H



Received from Dave at 3/23/2019 11:33 PM UTC:

Hi Jim,

Ok, I will see if the local shops know of them. I already found them under "gas dispersion tubes" too online but those scientific ones are pricey. Iam sure I will hunt one down...

Thanks,

Dave
Jim Higgins
 

Received from Dave at 3/23/2019 11:41 PM UTC:

Plastic tube will work and it's easy enough to drill holes in it. But can't we drill holes in glass tubes with our carbide bits?? Or would we break more of them than its worth? If a person were to try that, what size carbide would be strong enough without being excessive in size I wonder?

I have no idea, but for sure a fairly tiny hole can pass a lot of air at a fairly low pressure, so unless the holes are really really tiny the hole that's highest in the tank (least back pressure) will emit most of the air... defeating the purpose of having a number of holes.

I've arrived at the point that were I starting out I'd just use a straight piece of rigid glass or plastic tubing and be done with it. ;-)

Jim H
Jim Higgins
 

It's pretty much moot now since what I was describing originally seems to no longer be available from aquarium supply stores... and from lab supply houses will run close to $300.

That said, I wasn't describing a fritted glass filter. Picture a piece of glass tubing 1/4" diameter and long enough to reach the bottom of a container. Picture the last 1/2" or so being about 1/2" in diameter and made entirely of fritted (porous) glass, no hole in the end. So all the air pumped down the tube comes out thru the fritted glass as very small bubbles. These things are all designed with a pore size that will produce bubbles using very low pressure, like from an aquarium pump.

You're right that fritted glass funnels have porous plates with a variety of pore sizes... the thing about that being that some pore sizes can be so small that the surface tension of the etchant solution may not allow gas to pass at such a low pressure. They're used with a vacuum flask and maybe an 80% or more vacuum to draw solution thru them. And heaven help you if you plug one up by using it in a solution that can generate a precipitate that won't readily dissolve in a fresh, rejuvenated solution. There are special techniques for cleaning these filters if they become stopped up and most of them are seriously dangerous in the hands of casual PCB makers. That and they're all hugely expensive. Not recommended even if you just won the lottery. ;-)

But if you can beg one from a local college or lab that's being tossed out for maybe having a chipped rim... because they don't have anyone who knows you can just fire polish out the chip (or just ignore it)... go for it!

Jim H



Received from designer_craig at 3/24/2019 01:17 AM UTC:

Actually in "chemistry lab terminology" they are called fretted glass filters. Generally, they are 1-3" dia funnel sort of like devices with a fretted glass disk down near the bottom. For filtering I assume they are available with various pore sizes, they will also work for generating very small bubbles.

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