Homebrew PCBs

Bruce,

The decimal point was where I wanted it to be, I simply approximated… Which is only two or three points above the high end
industrial/commercial production level for common usage at more or less ambient pressures and temperatures, according to what I have
since learned. I have read there are apparently some rather esoteric processes that use above 40%. I didn’t take the time to look
into that, it’s far over my head, and not to the point. My point was only how to reduce the solution, which I quickly learned was
not feasible. What I was after, was reducing my 10% concentration to roughly  a 37-38% concentration, as has been recommended by
many here for building a metal etchant, without spending a lot on chemical house pricing and special shipping. I finally found some
32% (referred to as Muriatic Acid) that I am now using to develop an etching process for tin/copper alloy.

Thanks,

Roger

 

From: Homebrew_PCBs@yahoogroups.com [mailto:Homebrew_PCBs@yahoogroups.com] On Behalf Of ikc46118
Sent: Tuesday, January 19, 2010 6:49 AM
To: Homebrew_PCBs@yahoogroups.com
Subject: [Homebrew_PCBs] Re: Reducing concentration of HCl from 10% to 40%

 

  

Are you sure you didn't slip a decimal point somewhere? This is a very concentrated acid, much more than you would need for PCB
etching.

A saturated solution of HCl in water is 37-38%. There is no such thing as 40% HCl.

Bruce

--- In Homebrew_PCBs@yahoogroups.com <mailto:Homebrew_PCBs%40yahoogroups.com> , "Roger Blair" <Roger.Blair@...> wrote:
>
> I wish to prepare some HCl/H2O2 etchant, and I have 10% HCl. (10% HCl is $5 per gallon, but 40% HCl which is what I need is a lot
> more expensive)
> 
> The solution as I see it is to reduce the 10% HCL solution to 40% concentration. I am thinking of using a Pyrex container on low
> temp lab hotplate (100°?) to `boil' off the H2O. (outdoors)
> 
> Since I know next to nothing about chemistry, not to mention whether this technique would actually produce what I need, I would
like
> to get some input here.
> 
> I have a general understanding of safety issues in handling chemicals, and wish to do this in a reasonably safe manner, BTW…
> 
> (I will be working with no more than 10 to 20oz. of 10% solution at a time, to minimize any environmental impact to me, and the
> surroundings.)
> 
> Any advice would be appreciated.
> 
> Thanks,
> 
> Roger
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
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>





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