Electroplating after applying a resist is a good idea. That'd work just fine.

I was never keen on ammonium persulphate, as a cheapskate hobbyist the mixture didn't last, unlike ferric chloride that lasts for ages, or even better (& cheaper!) cupric chloride that you can regenerate. And it doesn't stain everything brown either.

I have used graphite to electroplate non-conductive things, that's pretty simple. Vias might be a bit fiddly.

Tony

-----Original Message-----
From: [email protected] <[email protected]> On Behalf
Of Harvey White
Sent: Monday, 2 November 2020 3:06 AM
To: [email protected]
Subject: Re: [homebrewpcbs] RoHS question

It may have gotten more expensive over time. It was about 30 USD for a pint
the last time I bought it, and it does have some nasty stuff in it. It does work
well on a clean board, though.

One method of making PC boards was to put down a layer of positive
photoresist over a bare board, expose it with a positive of the artwork so
that when developed, copper would be exposed where you wanted there to
be a track. You'd then electroplate tin on the board, strip the resist and etch
it. You would have to use something like ammonium persulphate, which
does not attack tin. Regular Ferric chloride and CuCl etchants will not work.

If you were making double sided boards with plated through holes you'd drill
the holes first, dunk the board in a graphite solution, plate one ounce of
copper over that, then add resist and etch as normal. The tin plating would
also cover the inside of the plated through holes.

Haven't used any of these, I did toner transfer for double sided boards,
stitched top and bottom together, with the top and bottom boards being half
thickness and produced separately.

Harvey


On 11/1/2020 4:57 AM, Tony Smith wrote:

I never tried tin plating PCBs, from memory the stuff was expensive,
hard to get and went "off" quickly. Seemed like a lot of hassle for
little reward, I just sprayed boards with clear lacquer.

Out of curiosity I looked up chemical tin plating, and of course ENIG
comes up. The 'N' is nickel, and the 'G' is gold. Explains why it's
expensive I guess.

The other type of chemical nickel plating is a nickel phosphor
coating, not good for PCBs but ok for machinery parts.

It's occurred to me that if you were into milling PCBs you could
electroplate the copper board beforehand. I wonder if anyone does that.

Tony

-----Original Message-----
From: [email protected] <[email protected]> On

Behalf Of

Dave
Sent: Friday, 30 October 2020 1:58 AM
To: [email protected]
Subject: Re: [homebrewpcbs] RoHS question

Tony,

I tinned some of my first home made pcb's but never again. And
the

boards

I ordered are of the ENIG variety. No rocket science comes out of my

hobby.

:)

On 10/28/2020 3:08 PM, Tony Smith wrote:

Yes, we're in violent agreement.

Unless you're a manufacturer, RoHS (or whatever your local flavour
is) isn't a problem.

Space vehicles are exempt from these regulations, I guess they
figure not many of them are going to wind up in a landfill. For the
tin whiskers, the problem wasn't lead-free solder, it's the tin
plating on the copper tracks, something even hobbyists do. I think
they nickel plate stuff like spacecraft PCBs now.

Dunno if there is a chemical solution to do nickel plating on copper
like you do with tin, but electroplating nickel is really easy.

Tony

-----Original Message-----
From: [email protected] <[email protected]> On Behalf
Of Harvey White
Sent: Monday, 2 November 2020 3:06 AM
To: [email protected]
Subject: Re: [homebrewpcbs] RoHS question

It may have gotten more expensive over time. It was about 30 USD for a pint
the last time I bought it, and it does have some nasty stuff in it. It does work
well on a clean board, though.

One method of making PC boards was to put down a layer of positive
photoresist over a bare board, expose it with a positive of the artwork so
that when developed, copper would be exposed where you wanted there to
be a track. You'd then electroplate tin on the board, strip the resist and etch
it. You would have to use something like ammonium persulphate, which
does not attack tin. Regular Ferric chloride and CuCl etchants will not work.

If you were making double sided boards with plated through holes you'd drill
the holes first, dunk the board in a graphite solution, plate one ounce of
copper over that, then add resist and etch as normal. The tin plating would
also cover the inside of the plated through holes.

Haven't used any of these, I did toner transfer for double sided boards,
stitched top and bottom together, with the top and bottom boards being half
thickness and produced separately.

Harvey


On 11/1/2020 4:57 AM, Tony Smith wrote:

I never tried tin plating PCBs, from memory the stuff was expensive,
hard to get and went "off" quickly. Seemed like a lot of hassle for
little reward, I just sprayed boards with clear lacquer.

Out of curiosity I looked up chemical tin plating, and of course ENIG
comes up. The 'N' is nickel, and the 'G' is gold. Explains why it's
expensive I guess.

The other type of chemical nickel plating is a nickel phosphor
coating, not good for PCBs but ok for machinery parts.

It's occurred to me that if you were into milling PCBs you could
electroplate the copper board beforehand. I wonder if anyone does that.

Tony

-----Original Message-----
From: [email protected] <[email protected]> On

Behalf Of

Dave
Sent: Friday, 30 October 2020 1:58 AM
To: [email protected]
Subject: Re: [homebrewpcbs] RoHS question

Tony,

I tinned some of my first home made pcb's but never again. And
the

boards

I ordered are of the ENIG variety. No rocket science comes out of my

hobby.

:)

On 10/28/2020 3:08 PM, Tony Smith wrote:

Yes, we're in violent agreement.

Unless you're a manufacturer, RoHS (or whatever your local flavour
is) isn't a problem.

Space vehicles are exempt from these regulations, I guess they
figure not many of them are going to wind up in a landfill. For the
tin whiskers, the problem wasn't lead-free solder, it's the tin
plating on the copper tracks, something even hobbyists do. I think
they nickel plate stuff like spacecraft PCBs now.

Dunno if there is a chemical solution to do nickel plating on copper
like you do with tin, but electroplating nickel is really easy.

Tony

I never tried tin plating PCBs, from memory the stuff was expensive, hard to
get and went "off" quickly. Seemed like a lot of hassle for little reward,
I just sprayed boards with clear lacquer.

Out of curiosity I looked up chemical tin plating, and of course ENIG comes
up. The 'N' is nickel, and the 'G' is gold. Explains why it's expensive I
guess.

The other type of chemical nickel plating is a nickel phosphor coating, not
good for PCBs but ok for machinery parts.

It's occurred to me that if you were into milling PCBs you could
electroplate the copper board beforehand. I wonder if anyone does that.

Tony

-----Original Message-----
From: [email protected] <[email protected]> On Behalf
Of Dave
Sent: Friday, 30 October 2020 1:58 AM
To: [email protected]
Subject: Re: [homebrewpcbs] RoHS question

Tony,

? I tinned some of my first home made pcb's but never again. And the

boards

I ordered are of the ENIG variety. No rocket science comes out of my

hobby.

:)

On 10/28/2020 3:08 PM, Tony Smith wrote:

Yes, we're in violent agreement.

Unless you're a manufacturer, RoHS (or whatever your local flavour is)
isn't a problem.

Space vehicles are exempt from these regulations, I guess they figure
not many of them are going to wind up in a landfill. For the tin
whiskers, the problem wasn't lead-free solder, it's the tin plating on
the copper tracks, something even hobbyists do. I think they nickel
plate stuff like spacecraft PCBs now.

Dunno if there is a chemical solution to do nickel plating on copper
like you do with tin, but electroplating nickel is really easy.

Tony

-----Original Message-----
From: [email protected] <[email protected]> On Behalf
Of Dave
Sent: Friday, 30 October 2020 1:58 AM
To: [email protected]
Subject: Re: [homebrewpcbs] RoHS question

Tony,

? I tinned some of my first home made pcb's but never again. And the

I ordered are of the ENIG variety. No rocket science comes out of my

:)

On 10/28/2020 3:08 PM, Tony Smith wrote:

Yes, we're in violent agreement.

Unless you're a manufacturer, RoHS (or whatever your local flavour is)
isn't a problem.

Space vehicles are exempt from these regulations, I guess they figure
not many of them are going to wind up in a landfill. For the tin
whiskers, the problem wasn't lead-free solder, it's the tin plating on
the copper tracks, something even hobbyists do. I think they nickel
plate stuff like spacecraft PCBs now.

Dunno if there is a chemical solution to do nickel plating on copper
like you do with tin, but electroplating nickel is really easy.

Tony

Dave,

I doubt you need to worry about tin whiskers as a hobbyist... not due to the solder or to tin plated traces or parts. I consider the lower ability to "wet" the connection and higher required temperature for RoHS solder to be the larger drawbacks to using it.

73 de Jim, KB3PU



Received from Dave at 10/29/2020 14:55 UTC:

Jim,

I read about tin whiskers a long time ago but didn't much worry about them as I wasn't making pcb's etc then. I just read about them before you brought them up. I came to the conclusion that the "tin" was the problem and not the solder. After seen some microscopic images it looks pretty wild and plenty of room for disaster. In fact, I bought some Tinning solution but only used it once. I also bought the crystals but never used them. Now I have quickly advanced (with my most basic and useless projects) to getting my boards made. I am waiting for my first order to arrive hopefully next week. :) Then after I really any mistakes or things I should have done different, I will have learned something so it's all good.


On 10/28/2020 12:19 PM, Jim Higgins wrote:

RoHS isn't a requirement that applies to consumers, incl hobbyists who might tinker with the product. It applies only to manufacturers. We - hobbyists - can repair even brand new RoHS compliant gear using tin-lead solder if we want to.

RoHS is an EU thing dating from early 2003 that expanded industry wide because industry wants to do business with the EU. I have no idea how the low/no-lead portion of it was ever incorporated into products made for applications in space... since the problem of "tin whiskers" (Google it) in pure (or almost pure) tin solder was documented back when vacuum tubes were king and solid state didn't exist - in the early part of the 20th century.

We (the USA) have had at least one satellite failure and one nuclear plant malfunction due to tin whiskers. In the case of a satellite - even a big expensive commsat as was the case - it's not really convenient to go up there to fix a connection that's growing a whisker that has caused a short circuit even if the short hasn't caused permanent damage. RoHS solder formulation has improved since those days and conformal coating over completed boards takes care of any remaining risk. Conformal coatings in consumer products make repairs much more difficult.

Jim H

Jim,

I read about tin whiskers a long time ago but didn't much worry about them as I wasn't making pcb's etc then. I just read about them before you brought them up. I came to the conclusion that the "tin" was the problem and not the solder. After seen some microscopic images it looks pretty wild and plenty of room for disaster. In fact, I bought some Tinning solution but only used it once. I also bought the crystals but never used them. Now I have quickly advanced (with my most basic and useless projects) to getting my boards made. I am waiting for my first order to arrive hopefully next week. :) Then after I really any mistakes or things I should have done different, I will have learned something so it's all good.


On 10/28/2020 12:19 PM, Jim Higgins wrote:

RoHS isn't a requirement that applies to consumers, incl hobbyists who might tinker with the product. It applies only to manufacturers. We - hobbyists - can repair even brand new RoHS compliant gear using tin-lead solder if we want to.

RoHS is an EU thing dating from early 2003 that expanded industry wide because industry wants to do business with the EU. I have no idea how the low/no-lead portion of it was ever incorporated into products made for applications in space... since the problem of "tin whiskers" (Google it) in pure (or almost pure) tin solder was documented back when vacuum tubes were king and solid state didn't exist - in the early part of the 20th century.

We (the USA) have had at least one satellite failure and one nuclear plant malfunction due to tin whiskers. In the case of a satellite - even a big expensive commsat as was the case - it's not really convenient to go up there to fix a connection that's growing a whisker that has caused a short circuit even if the short hasn't caused permanent damage. RoHS solder formulation has improved since those days and conformal coating over completed boards takes care of any remaining risk. Conformal coatings in consumer products make repairs much more difficult.

Jim H

Jim,
There is a raft of information on tin whiskers at one of the NASA sites: Some really great (scary) photos

As you can see on the NASA site, there actually were several communications sat failures due to whiskers. The one that most people remember is the Galaxy 4 Panamsat. That is the one that was carrying most of the pager traffic in the US. I worked on equipment that went on the replacement sat. If ever there was a customer that was jittery and over protective about tin, that one was it. He was right!

As to how the tin got onto the sats, you will see several examples of things that were overlooked. "Everybody" knew that the leads on the ICs, transistors and most electronic parts were tin plated, so we had them solder dipped. We went out of our way to make sure the terminal posts we bought were solder plated, or solder dipped. When we inspected some of the terminal posts that looked odd for solder plate, we found that some were tin plated. At that point we stepped up our inspection for the finish, and we found that the suppliers were ignoring the solder requirement, and sending tin finish because they were in stock. Other structural hardware sometimes was tin plated. Several corrective actions were taken to replace them.

Conformal coat does not protect against tin whiskers. The whiskers are really sharp, and push through the coatings. They also take on all kinds of odd shapes, and have been seen to curl over and touch each other. They also can break off, and become lodged in areas that are not coated.

Harvey

_._,_._,_

---

Yes, we're in violent agreement.

Unless you're a manufacturer, RoHS (or whatever your local flavour is) isn't
a problem.

Space vehicles are exempt from these regulations, I guess they figure not
many of them are going to wind up in a landfill. For the tin whiskers, the
problem wasn't lead-free solder, it's the tin plating on the copper tracks,
something even hobbyists do. I think they nickel plate stuff like
spacecraft PCBs now.

Dunno if there is a chemical solution to do nickel plating on copper like
you do with tin, but electroplating nickel is really easy.

Tony

RoHS isn't a requirement that applies to consumers, incl hobbyists who might tinker with the product. It applies only to manufacturers. We - hobbyists - can repair even brand new RoHS compliant gear using tin-lead solder if we want to.

RoHS is an EU thing dating from early 2003 that expanded industry wide because industry wants to do business with the EU. I have no idea how the low/no-lead portion of it was ever incorporated into products made for applications in space... since the problem of "tin whiskers" (Google it) in pure (or almost pure) tin solder was documented back when vacuum tubes were king and solid state didn't exist - in the early part of the 20th century.

We (the USA) have had at least one satellite failure and one nuclear plant malfunction due to tin whiskers. In the case of a satellite - even a big expensive commsat as was the case - it's not really convenient to go up there to fix a connection that's growing a whisker that has caused a short circuit even if the short hasn't caused permanent damage. RoHS solder formulation has improved since those days and conformal coating over completed boards takes care of any remaining risk. Conformal coatings in consumer products make repairs much more difficult.

Jim H

RoHS doesn’t bother a lot of people, even if you’re repairing old gear where the tracks fall off if you look at them funny you’re still allowed to use leaded solder.? They’re full of lead and god only know what so redoing a couple of joints in lead-free isn’t going to save too many whales.

?

It’s not all that complicated, just mainly nit-picking pedantic pen-pushing stuff.? I work in IT dealing with money, so I’m used to that sort of thing.

?

If you making laptops or whatever you get a statement from whom you buy solder, PCB, wire etc from that says how much lead is in it.? You staple all those together and send it off to the EU and say “our laptops are made from this” and everyone is happy.? Of course this means you can’t buy the cheapest solder from Honest Johns Alibaba shop and things are a bit more difficult if you actually make solder, but that’s not most of us.

?

Tony

?

?

-----Original Message-----
From: [email protected] <[email protected]> On Behalf
Of Jim Higgins
Sent: Thursday, 29 October 2020 4:19 AM
To: [email protected]
Subject: Re: [homebrewpcbs] RoHS question


RoHS isn't a requirement that applies to consumers, incl hobbyists who

tinker with the product. It applies only to manufacturers. We - hobbyists

can repair even brand new RoHS compliant gear using tin-lead solder if we
want to.

RoHS is an EU thing dating from early 2003 that expanded industry wide
because industry wants to do business with the EU. I have no idea how the
low/no-lead portion of it was ever incorporated into products made for
applications in space... since the problem of "tin whiskers" (Google it)

(or almost pure) tin solder was documented back when vacuum tubes were
king and solid state didn't exist - in the early part of the 20th century.

We (the USA) have had at least one satellite failure and one nuclear plant
malfunction due to tin whiskers. In the case of a satellite - even a big
expensive commsat as was the case - it's not really convenient to go up

to fix a connection that's growing a whisker that has caused a short

even if the short hasn't caused permanent damage. RoHS solder formulation
has improved since those days and conformal coating over completed boards
takes care of any remaining risk. Conformal coatings in consumer products
make repairs much more difficult.

Jim H



Received from Tony Smith at 10/28/2020 04:43 UTC:

RoHS doesn't bother a lot of people, even if you're repairing old gear
where the tracks fall off if you look at them funny you're still
allowed to use leaded solder. They're full of lead and god only know
what so redoing a couple of joints in lead-free isn't going to save too

whales.

It's not all that complicated, just mainly nit-picking pedantic
pen-pushing stuff. I work in IT dealing with money, so I'm used to that

of thing.

If you making laptops or whatever you get a statement from whom you buy
solder, PCB, wire etc from that says how much lead is in it. You staple
all those together and send it off to the EU and say "our laptops are
made from this"&#65533; and everyone is happy. Of course this means you
can't buy the cheapest solder from Honest Johns Alibaba shop and things
are a bit more difficult if you actually make solder, but that's not most

Tony

RoHS doesn't bother a lot of people, even if you're repairing old gear where the tracks fall off if you look at them funny you're still allowed to use leaded solder. They're full of lead and god only know what so redoing a couple of joints in lead-free isn't going to save too many whales.

It's not all that complicated, just mainly nit-picking pedantic pen-pushing stuff. I work in IT dealing with money, so I'm used to that sort of thing.

If you making laptops or whatever you get a statement from whom you buy solder, PCB, wire etc from that says how much lead is in it. You staple all those together and send it off to the EU and say "our laptops are made from this"? and everyone is happy. Of course this means you can't buy the cheapest solder from Honest Johns Alibaba shop and things are a bit more difficult if you actually make solder, but that's not most of us.

Tony

?

Tony,

? Looks complicated but as Jim said I (we) shouldn't even worry about it as hobbyists.

Dave

Ah yes, I did mean I still use the leaded stuff, maybe I should stop chewing it.

?

And at least in Australian, you can buy it easily enough and it’s $10/roll cheaper than lead-free, so yay for us I guess.

?

As far as RoHS, Wikipedia has a reasonable write-up: .? Huh, there’s 10 things on the list now.

?

Weighing by individual materials eliminates cheating.? Say your cable is a metre long, weighs 1000 grams and the solder joints have 2 grams of lead, at 0.2% it’s double the limit.? No problems, just make the cable twice as long.? You still have the same amount of leaded solder but now 2 grams of lead in a 2000 gram cable is 0.1%, so it passes!? Everyone happy!

?

Under RoHs both cables have 40% lead in the solder, so you need to sort that out.

?

They don’t make the limit 0% because easier said than done, plus a tiny little bit of lead in steel & brass makes it easier to machine.

?

Tony

?

?

?

From: [email protected] <[email protected]> On Behalf Of Roy via groups.io
Sent: Tuesday, 27 October 2020 1:06 PM
To: [email protected]
Subject: Re: [homebrewpcbs] RoHS question

?

I think you meant to type, "leaded" instead of, "lead free" - your 2nd link is to classic 60-40 Sn-Pb solder. Some of the early Pb free solders were genuinely unpleasant to work with, enough so that whoever did the plumbing in my house chose to silver braze everything instead of using whatever Pb free soft solder was available locally.

Roy

?

Ah yes, I did mean I still use the leaded stuff, maybe I should stop chewing it.

?

And at least in Australian, you can buy it easily enough and it’s $10/roll cheaper than lead-free, so yay for us I guess.

?

As far as RoHS, Wikipedia has a reasonable write-up: .? Huh, there’s 10 things on the list now.

?

Weighing by individual materials eliminates cheating.? Say your cable is a metre long, weighs 1000 grams and the solder joints have 2 grams of lead, at 0.2% it’s double the limit.? No problems, just make the cable twice as long.? You still have the same amount of leaded solder but now 2 grams of lead in a 2000 gram cable is 0.1%, so it passes!? Everyone happy!

?

Under RoHs both cables have 40% lead in the solder, so you need to sort that out.

?

They don’t make the limit 0% because easier said than done, plus a tiny little bit of lead in steel & brass makes it easier to machine.

?

Tony

?

?

?

From: [email protected] <[email protected]> On Behalf Of Roy via groups.io
Sent: Tuesday, 27 October 2020 1:06 PM
To: [email protected]
Subject: Re: [homebrewpcbs] RoHS question

?

I think you meant to type, "leaded" instead of, "lead free" - your 2nd link is to classic 60-40 Sn-Pb solder. Some of the early Pb free solders were genuinely unpleasant to work with, enough so that whoever did the plumbing in my house chose to silver braze everything instead of using whatever Pb free soft solder was available locally.

Roy

Received from Dave at 10/26/2020 23:23 UTC:

I bought some USB cables and noticed the RoHS sticker on them and never really read much about the standard so I have a few questions. It states something about 0.1% lead is allowed but in the case of cables, does that take in the whole weight of the cable??

No, it's based only on the weight of the components that are expected to contain lead... in this case the solder used can contain only 0.1% lead.

Actually ROHS stands for "Restriction of Hazardous Substances" and it refers to a dozen or so other substances, not just lead, and the allowed percentage of each varies according to the substance involved... but we're just talking lead in this case.

Or on a circuit board, how is the math actually based for the allowable limit of lead in the solder.

It's based on the weight of the solder alone.

And last but not least, I have never ever used no lead solder. Is is a good idea to buy some for future reference in case of reworking something that followed the standard?

If you're a commercial enterprise, repairing an ROHS product with non-ROHS solder would be a be no-no. In the case of a hobbyist making things for himself and a few friends I wouldn't touch ROHS solder... not even for repair of ROHS products. In general it doesn't wet the parts nearly as well as tin-lead solder does so you're more likely to get a good joint with tin-lead... and wetability aside, during a repair you're also far less likely lift a PCB pad due to the higher temperature ROHS solder requires.

And if yes, are all no lead solders the same or do the have choices using differing amounts of the ingredients to make it?

Thanks
Dave

They're not all the same. Neither are all lead containing solders.


Jim H

It doesn't really matter what the item is, the lead (or whatever) percentage
is applied to each material used.

So the cable is made of copper, steel, solder, a few different plastics and
each of these needs to have under 0.1% lead. Kinda makes sense when you
think about it, although documenting it would be "fun".

For hobbyist it doesn't matter much what you use. Lead-free solders seem to
have improved, I was at my soldering something at a friend house and only
after I'd finished I noticed the solder was lead free. I think, like many
things, the "lead free is terrible!!" rantings and raving are from people
just repeating what they've read on the internet.

Pretty sure it was this stuff:
, tin
with 0.7% copper. Whatever it was, it worked like normal lead-free, I'm
sure there are alloys that are terrible.

That said, I use lead free because I've still got heaps of it left. And
besides, why switch when it's still cheaper:


Tony