Thank You, Donald!
The HCl concentration is 10%. I overlooked that part… I appreciate the breakdown (especially the reasoning, as it provides me some insight as to how to go about proportioning this stuff) This will get me started.
Regards,
Roger
From:
Homebrew_PCBs@yahoogroups.com [mailto:
Homebrew_PCBs@yahoogroups.com] On Behalf Of Donald H Locker
Sent: Friday, December 25, 2009 7:19 AM
To: Homebrew PCBs
Subject: Re: [Homebrew_PCBs] Looking for a photo etching vendor
Using 1.2 as the specific gravity of HCl (I didn't look it up, but that should be close enough for this approximation)
Your recipe calls for 10g FeCl / (100g H2O + (8 to 30) (or so)g HCl + 10g FeCl) => FeCl is about 10/118 to 10/140 or 8.5 to 7% by weight in your recipe. HCl comprises about 7% at the low end and 20% at the high end.
I would use about 100ml of the MG brew per 500ml final solution and 30 to 100ml HCl. Reasoning: 40% by weight diluted to 8% by weight is a 1:5 dilution. The MG 415 should comprise 1/5th of the final solution, with HCl making up the remainder. With only 1% HCl in the MG 415, most of your 7 to 20% has to come from the addition of HCL when making up your etchant. 100ml HCl would be close to 20% of the final, so 30ml would be near the 7% level.
I'm playing very loose with the volume/mass distinction and assuming that the recipe requirements aren't _too_ critical. Especially given the range specified for HCl and the lack of a concentration spec for it.
Remember to always add acid to water, and wear good safety gear - you only have one pair of eyes and one skin.
Donald.
----- Original Message -----
From: "Roger Blair" <Roger.Blair@... <mailto:Roger.Blair%40Comcast.net> >
To: "Homebrew PCBs" <Homebrew_PCBs@yahoogroups.com <mailto:Homebrew_PCBs%40yahoogroups.com> >
Sent: Thursday, December 24, 2009 4:36:53 PM GMT -05:00 US/Canada Eastern
Subject: RE: [Homebrew_PCBs] Looking for a photo etching vendor
I found a formula for tin-copper alloys that I would like to try, consisting of: Distilled water or methanol, 100 ml; Hydrochloric
acid, 5-25 ml and Ferric chloride (powder) 10 grams.
Can someone here correlate grams of the powder to milliliters of (MG Chemicals 415) solution, (Ferric Chloride 40% by weight,
Hydrochloric acid 1% by weight - 5ppm)?
Being totally chemistry ignorant, and as I already have the liquid solution.
TIA for any enlightenment on this.
Regards,
Roger
From: Homebrew_PCBs@yahoogroups.com <mailto:Homebrew_PCBs%40yahoogroups.com> [mailto:Homebrew_PCBs@yahoogroups.com <mailto:Homebrew_PCBs%40yahoogroups.com> ] On Behalf Of Stefan Trethan
Sent: Tuesday, December 22, 2009 9:44 AM
To: Homebrew_PCBs@yahoogroups.com <mailto:Homebrew_PCBs%40yahoogroups.com>
Subject: Re: [Homebrew_PCBs] Looking for a photo etching vendor
People might be reluctanct because of the tin in the bronze. I'm not
sure what it will do, but I'd avoid putting anything other than copper
in my etching tank.
You can always try with a one-time use small batch of etchant first.
HCl and H2O2 (3% dilute) will do the trick.
ST
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