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Subject: Re: [Homebrew_PCBs] Reducing CuCl etchant foaming

From: Sam Rod <mail4sam@...>
Date: 2014-02-16

Perhaps you only need more room for the foam? Or reduce the liquid content translating into more room for foam. Put another way if your etchant is working.... The foam control is a small easily solved byproduct. :)

Sent from my iPhone

On Feb 16, 2014, at 11:30 AM, Philip Pemberton <ygroups@...> wrote:

 

Hi there,

I've been having problems with my CuCl etching bath (and to a lesser
degree my FeCl etching bath). When I turn the air pump on, the etchant
starts to foam -- if I have the air valve set above a few percent, it'll
foam over the top of the tank in a few minutes.

Acid molarity was around 2.3M last time I checked, with a specific
gravity of around 1.3.

Does anyone know of a way I could reduce the amount of foam being
produced? Reducing airflow only slows down the process, it doesn't stop
it; the foam seems also seems to be quite resistant to being dispersed
and unusually long-lasting. The foam I get when the FeCl tank is being
aerated too quickly usually disperses inside a minute - this stuff takes
a good half hour to revert to a liquid state.

Thanks,
--
Phil.
ygroups@...
http://www.philpem.me.uk/