Homebrew PCBs

On Fri, 23 Nov 2007, Dave wrote:

> Is there some simple but professional plans to build an etchant tank? I
> mean with heater and agitation, not just a jar and manual labor:)

I've found a plastic food-style container and manual agitation works fine.
All I do is full a large outer tank with hot water, and float the ferric
chloride container in the hot water. This also allows me to give the board
a quick dunk in the water to see how its progressing. Etching times are
pretty damned quick.

> (heater, pump, etc). I was also planning on using ferric chloride as I
> have a bottle from RatShack from when I started getting interested in
> this some years ago. I know there are other etchants and comments are
> welcome on whats best but I think other than the staining and inability
> to see your boards progress, ferric chloride is probably as good as the
> others??

I've not used other chemicals, so I can't comment on them, but ferric
chloride is less nasty than most, and it lasts a long time. I'm still
using a 250ml batch I made up in January, and I've done loads of boards in
it (some double sided 6in by 4in boards). I do tend to put a large "copper
pour" area (just drag a polygon over the design once I've finished it) or
ground planes, which reduces the amount of copper that must be removed.
(Although on the flip side, I also tin my boards so I go through more
tinning solution!)

Someone told me that a bit of table salt can help rejuvinate ferric
chloride, too. I did add some when I thought the solution was getting
tired.