I’m currently enjoying doing some etching. I first started off
etching sterling using nitric acid (at approx 25% strength). I had
the pieces with the design facing upwards and of course had to
contend with getting rid of the horrible “sludge” from the low parts
of the design. I didn’t much like the nitric acid for intricate
designs, as it gives too much of a chewed up look, being very
aggressive. So I’ve now switched to ferric nitrate, which gives a
much crisper etch. I decided to try and avoid the sludge, by using
foam, with the silver suspended underneath. However, there was still
just as much sludge hindering my etching, as there had been when I
had the silver the other way up!!! I’m a tad confused by this.
Anyway, I found it difficult to remove said sludge, and ended up
scrubbing it away using a wet, soft nylon toothbrush dipped in
bicarbonate of soda as an abrasive agent. It did the trick, but I
was wondering whether there’s a better, more effective way of
removing it, both during etching, so as to go on to achieve a deeper
etch, and without damaging my PNP blue resist, and after the desired
depth is achieved? What do other folks use?
Thanks in advance for any suggestions.