"I had a lot of problems with the ferric chloride while the least problems with undercutting with the new muriatic acid + HCl (becomes cupric chloride) solution. "
Your chemistry is very confusing. Muriatic acid is HCl. The concentrations from your recipe also do not make sense. I am sure there is a simple explanation, such as some typos.
John
----- Original Message -----
From: bruce_fleming
To: Homebrew_PCBs@yahoogroups.com
Sent: Sunday, December 02, 2012 10:23 AM
Subject: [Homebrew_PCBs] Re: Cupric Chloride Fumes
The etching solution is made from muriatic acid (1 part) added to HCl (2 parts). Here is the link on Instructables:
http://www.instructables.com/id/Stop-using-Ferric-Chloride-etchant!--A-better-etc/#step1
I had a lot of problems with the ferric chloride while the least problems with undercutting with the new muriatic acid + HCl (becomes cupric chloride) solution. With the ferric chloride, the pcb had thin traces which I think are attributed to undercutting. The cupric chloride did eat away some of the traces but not as much as the ferric chloride.
There were some other factors with the ferric chloride that I can work on eliminating. One of them would be to heat the solution to working temperature varying from 45 degrees Celsius to 55 degrees Celsius and when ready, then place the board in the etchant.
--- In Homebrew_PCBs@yahoogroups.com, "John Anhalt" <janhalt@...> wrote:
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> "etch with muriatic acid so you do not have throw out your solution when saturated with copper."
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> Are you talking about the peroxide + muriatic acid etchant or the one that is based initially on copper (II) chloride? While it is true that the former eventually becomes the latter, at the outset, they are not the same. The peroxide etchant is more aggressive. I tried using the peroxide method with a photoresist, and it eat the resist that I use (Injectorall). That might be part of your problem.
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> Of the three etchants you mention, ferric chloride is the easiest to use and gives the best results in terms of minimal undercutting, a broad endpoint, and fine lines. I suggest using that until you get a method working. When I switched to cupric chloride, the biggest change I noticed was at the end point. It was easier to over etch the PCB.
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> John
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> ----- Original Message -----
> From: bruce_fleming
> To: Homebrew_PCBs@yahoogroups.com
> Sent: Saturday, December 01, 2012 4:16 PM
> Subject: [Homebrew_PCBs] Cupric Chloride Fumes
>
>
>
> Hi all. I am new to this forum and am working on etching. The ferric chloride has been tried a few times. While searching for better ways to etch using ferric chloride I came across an Instructables on how to etch with muriatic acid so you do not have throw out your solution when saturated with copper.
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> When I tried the Cupric Chloride the I made sure the area was well ventilated but I believe the cold slowed down the etching process so much that the traces also were partially destroyed.
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> Has anybody found a fume hood that will handle cupric chloride? Etching outside or with a window open is not a good option in the winter.
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