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Subject: Re: [Homebrew_PCBs] Re: CuCl etching - the aftermath

From: Anthony Toft <toftat@...>
Date: 2004-10-06

> Glad to hear of your success. That's definitely the HCL doing the
> etching. You can get 1 G quantities at home depot, lowes, ...

They had 2 one gallon containers sold together in a box. As I told my
pool owner friend, if I thought I'd use even half of it I wouldn't have
minded, but it's a little excessive when I really only wanted approx 1.5
ounces, and I'd have to move it in a months time (changing houses)

> acid and water is exothermic. always add acid to water, never water

This I remembered from chemistry class, but I didn't have a definate
water, so I added HCl to H202 figuring adding less to more was
preferable (and at 3% the H2O2 had more water in it) I also did this
outside in the Florida humidity, the HCl container was 'steaming' after
use...

> I noticed bubbles when I had plenty of H2O2. It will eventully go

Ok, so I won't worry about it.

> flat. I doubt that it will build up that much pressure but for piece
> of mind, you can leave the lid slightly loose.

I will squeeze the bottle before sealing it, give the gas somewhere to
go.

> Probably CuCl. I would recommend something beefier than latex gloves.

These are the onetime use ones they use in labs, then they hit the
trash.

> I'm going to get a lab apron next time I hit the chem supply place.

I wore old clothes in case of splashes and took great care. A friend at
work used to work with chemicals and has plenty of horror stories (hence
working outside, gloves and safety glasses)

> I'm interested in your second etching session. If its anything like
> mine (hope not) you will have to add H2O2. My sessions with the same
> recipe went something like this:

This might not happen for a few months, there isn't much on my project
list at the moment, I can say that at the moment it's a gumball green. I
haven't found higher H2O2 yet, so if it refuses I will seed some new
stuff and just add it to my waste bottle. When I have a bunch I will
take it to the waste disposal. As I said, I don't use much...

> I'm not super happy with this stuff yet. If I can either find a cheap

My main happy was that I could see what was going on.

> stands, having to buy H2O2 at $4/oz really is bad economics. But if

Ouch!

> it can be made to work the the displosal benefits will make it all
> worthwhile.

That's what I am hoping for, I regen'ed my FeCl several times before it
just didn't work any more (about 1 year later) but I'd rather not throw
it away if possible.

--
Anthony Toft <toftat@...>
I'm Anton, and I approve this message