For my aerator, I use an aquarium pump and plastic tubes from the pet store. I would not recommend the stone variety.
I agree with you on the photoresist. Occasionally, a seller of small quantities will appear on ebay. I haven't tried it yet, but have wanted to ever since first reading about it several years ago. I am afraid the manufacturer for my pre-sensitized boards (Injectorall, available from DigiKey) is about to close shop.
John
----- Original Message -----
From: Philip Pemberton
To: Homebrew_PCBs@yahoogroups.com
Cc: John Anhalt
Sent: Monday, March 19, 2012 5:42 PM
Subject: Re: [Homebrew_PCBs] Rejuvenating ferric chloride etchants
On 19/03/12 21:18, John Anhalt wrote:
> Hi Phil,
>
> This describes the whole process with cupric chloride: http://members.optusnet.com.au/eseychell/PCB/etching_CuCl/index.html
>
> I have been using it for several years. Too much acid leads to undercutting, but the amount of acid is difficult for most DIY'ers to access. Go by specific gravity and color.
OK, it looks like what I've ended up with is somewhat close to that --
almost black liquid, but with green foam (and foam it does: I had to
turn the air pump right the way down after it foamed over the side of
the etch tank and onto the concrete floor!)
There's a slight yellow-brown tint to the green, so there's some FeCl3
left in there (or at least some iron-based compound), but I don't think
there's much...
Etch time with air on one-quarter is around 10 minutes, if even that.
Now if only I could get my hands on dry-film photoresist in quantities
less than "two bloomin' great heavy reels" (which seems to be Mega's
preferred sales unit, at a cost of £100-odd plus VAT)...
--
Phil.
ygroups@...
http://www.philpem.me.uk/
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