Homebrew PCBs

http://www.efma.org/publications/guidance/section16.asp

"Release of phosphorus oxides (toxic) from thermal decomposition and of
hydrogen from reaction with metals."

" 10.3 Materials to avoid
Bases, aluminium, copper, mild steel, brass, bronze"

It is likely that The ph control product used in hydroponics does contain a
bit of sulfuric. But its seems that the phosphorus does react independently
with the copper.

This is probably way more in-depth than you want but
http://dragon.klte.hu/~gasparv/reprints/jpc_chaos_control.pdf

JT
http://www.soundclick.com/jtsound
----- Original Message ----- 
From: "dsv1486" <darrell.vandenberg@...>
To: <Homebrew_PCBs@yahoogroups.com>
Sent: Wednesday, April 07, 2004 12:46 PM
Subject: [Homebrew_PCBs] Re: Phosphoric Acid Etch


> It was very inexpensive as I purchased it from a hydroponics shop
> that was closing. It was $5 for 5 gallons of 89% concentration. I
> did not notice the evaporation issue and while etching I did not
> notice any smell. Does anyone know what chemical reaction is going
> on?? I think it is making copper phosphate. I will try another test
> and let everyone know how it went.
>
>
>
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