How do I dispose of exhausted etchant ?
________________________________
From: Harvey White <
madyn@...>
To:
Homebrew_PCBs@yahoogroups.comSent: Mon, February 21, 2011 9:48:15 PM
Subject: Re: [Homebrew_PCBs] FR-4 Copper Clad and Etchant mix
On Mon, 21 Feb 2011 18:31:50 -0800 (PST), you wrote:
>ok thanks .. NEVER took chemistry .. lol
>I will look in the archives ..
>Thanks for the great info ..
>I guess I should mix small amounts unless I plan on using
>it up in 30 days .. is it photo sensitive?
>
Not photo sensitive. Since it's an acid, it will eat holes in your
shirt. I use it outside, having heated it a bit and bubbled air
through it. When brand new, it etches boards in about 5 or 6 minutes
at the most. After a long while, it stretches to 20 minutes.
If you're in the US, then the acid is about 8 dollars a gallon, and
the H2O2 (peroxide) is about 1.50 to 2.00 a quart. You want the 3%
stuff sold in the drugstores. It is also known as 30 vol, a measure
of the amount of oxygen it will produce.
You start off with one etchant, you end up with another. Some will
immediately add about 4-6 oz of copper to convert to the CuCl etchant.
I let the boards do it.
Bottom line: it's cheap. I use a cereal container (plastic),
relatively acid proof, and do 4 by 6 inch boards (actual size before
trimming about 5 by 7 inches). I can do two of them at once or more
than two depending on what the board size is.
Air bubbling moves the etchant around, and gives the etchant the air
it needs. I use about 5 quarts at a time, due to the board and tank
size.
Harvey
>
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>________________________________
>From: Harvey White <madyn@...>
>To: Homebrew_PCBs@yahoogroups.com
>Sent: Mon, February 21, 2011 9:28:42 PM
>Subject: Re: [Homebrew_PCBs] FR-4 Copper Clad and Etchant mix
>
>
>On Mon, 21 Feb 2011 18:20:02 -0800 (PST), you wrote:
>
>>I mix the acid into the peroxide? Not the other way around?
>>and do I have to mix slowly? is there heat generation or splattering?
>>from the mixing process ?
>>
>
>ALWAYS add acid to water. Heat will be generated, but splattering
>will be minimized that way. Mix slowly. Check general chemistry lab
>rules.
>
>Harvey
>
>>
>>
>>
>>________________________________
>>From: Harvey White <madyn@...>
>>To: Homebrew_PCBs@yahoogroups.com
>>Sent: Mon, February 21, 2011 8:43:46 PM
>>Subject: Re: [Homebrew_PCBs] FR-4 Copper Clad and Etchant mix
>>
>>
>>On Mon, 21 Feb 2011 17:29:51 -0800 (PST), you wrote:
>>
>>>FR-4 doesnt have to be green colored? Correct ?
>>
>>I've used black, good for displays, blocks light.
>>>
>>>Other question .. for making etchant ..
>>>I saw 2 parts peroxide to one part muriatic acid ( 34% hydrochloric acid )
>>>and I saw 3 to mix as well ..
>>>Is it crucial ? I mean I guess the only thing that it would change is the
>>>etching
>>>times .. and the fumes LOL .. ??
>>
>>I've used 4 parts peroxide to 1 part acid. Don't think it's
>>absolutely critical.
>>
>>Harvey
>>
>>>
>>>Randy
>>>
>>>
>>>
>>>
>>>
>>>
>>>------------------------------------
>>>
>>>Be sure to visit the group home and check for new Links, Files, and Photos:
>>>http://groups.yahoo.com/group/Homebrew_PCBsYahoo! Groups Links
>>>
>>>
>>>
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>>------------------------------------
>>
>>Be sure to visit the group home and check for new Links, Files, and Photos:
>>http://groups.yahoo.com/group/Homebrew_PCBsYahoo! Groups Links
>>
>>
>>
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>------------------------------------
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>Be sure to visit the group home and check for new Links, Files, and Photos:
>http://groups.yahoo.com/group/Homebrew_PCBsYahoo! Groups Links
>
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