Archive of the former Yahoo!Groups mailing list: Homebrew PCBs

----- Original Message -----
From: "Bruno St-Laurent" <bsl88k@...>
To: <Homebrew_PCBs@yahoogroups.com>
Sent: Tuesday, January 03, 2006 2:48 PM
Subject: [Homebrew_PCBs] CUCL Temperature , etch time ?????


> Hi guys I'm new using the homebrew mix of HCL 30% and H2O2 3%, and
> would like to know what is the best temperature for good etch time??? ,
> right now when i do a fresh mix, the etch time is really fast around 5
> minutes , but if a week later i want to reuse that mix now clear green
> color my etch time goes up to more than 30 minutes!!!!!!

It should be blue for proper etching. You need to add some concentrated
H2O2, to oxidise the green cuprous chloride to cupric chloride. Adding the
3% H2O2 will make the solution too dilute. Or, just mix it fresh each time.

Leon

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