Who cares what the disadvantages may be of something you can't get, and would
be foolish to even try, in the first place?

But let's introduce something really annoying to the discussion... some
facts. 35% H2O2 holds its strength very well when properly stored. In an air
conditioned environment, with no contamination having been introduced, loss
of strength by 1% in a year wouldn't be surprising. Contaminate it and it can
"lose its strength" so fast that the bottle explodes.

"They" didn't stop selling it. A legitimate lab can buy all it needs from any
of a number of chemical supply houses - none of which are named "Amazon," and
few if any of which will ship to a residential address. The cost is
prohibitive for a hobbiest because of the legally imposed packaging
requirements for shipping anything over 12% H2O2.







Received from dale.chatham at 3/24/2019 06:13 AM UTC:

>I wonder if they stopped selling 35% because it is used to make explosives?
>
>Another disadvantage of 35% is that once opened, it doesn't stay 35% for long.
>
>
>
>-------- Original message --------
>From: Jim Higgins <HigginsJ@...>
>Date: 3/23/19 22:11 (GMT-06:00)
>To: homebrewpcbs@groups.io
>Subject: Re: [homebrewpcbs] Bubble Tank DIY Plans
>
>Received from Dave at 3/24/2019 02:25 AM UTC:
>
> >I have a bottle of FeCI from RatShack I bought 15 years or more ago still
> >unopened. Read all kinds of stories about that stuff. Being I am a noob just
> >starting I read all the comments and I may try different methods so this is
> >just another note in my toolbox.
>
>
>I don't like ferric chloride (FeCl3) because the solution is too dark to
>observe the progress of the etching and it doesn't change color appreciably
>as it becomes spent so you don't know it's spent until it doesn't work. That
>and it makes for stains that are very hard to remove.
>
>That said, if none of that bothers you, it works just fine for etching copper
>and it can be rejuvenated by bubbling air thru it. Etch and rejuvenate enough
>and you'll need to add a bit of HCl too. I guess you'll know when adding a
>bit of HCl is necessary when it won't etch copper properly even after
>extensive rejuvenation. The color of the solution prevents seeing when it
>isn't properly rejuvenated so you can't tell when to add HCl until you're
>disappointed in the results.
>
>I see people saying ferric chloride is "sludgy." If it's sludgy it's probably
>badly spent and/or overconcentrated from repeated use and repeated
>rejuvenation. sludgy solution just needs rejuvenating with bubbled air (or
>H2O2) and probably a bit of HCl also. And some water if too heavily loaded
>with copper. Properly maintained solution won't be sludgy. The thing is... at
>this point you're also etching with the cupric chloride the solution also
>contains... so just start out with cupric chloride and have a solution that's
>nicer to work with and easier to see if it needs rejuvenation.
>
>Jim H
>
>
>
>
>
>