Homebrew PCBs

On 16/02/14 16:41, Sam Rod wrote:
> 
> 
> 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. :)

The tank is 1.5 litres, filled with 500ml of etchant, leaving 6-8 inches
of space from the liquid level to the top of the tank. The foam was
overflowing the tank after about ten minutes.

I really don't think 500ml of etchant should produce that much foam!

Aeration is an aquarium air-bubbler hose ("air curtain"), a little like
this one: http://www.ebay.co.uk/itm/181124311130
The difference is, mine has a right-angle connector on the end instead
of a straight fitting.

I checked the chemistry a few minutes ago -- bath parameters are:

  Acid molarity      1.3 Molar
  Specific gravity  ~1.225

I left a board etching earlier this afternoon - after half an hour the
CuCl had taken a fair bit of copper off but seemed to stop etching as it
got towards the end. I ended up dumping the board in the ferric chloride
tank to finish it off.

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