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Di Sandland
18-08-2009, 03:03 PM
Does anybody on here etch brass to make impression plates? Just to clarify myself - I'm thinking - brass etchings, roll on silver clay...

mizgeorge
18-08-2009, 03:53 PM
I've done a bit of salt water etching to make plates which I then use with a rolling mill. I used a technique from Art Jewelry mag (or was it Art Jeweler)

Di Sandland
18-08-2009, 05:09 PM
Thanks George. I started getting Art Jewelery mag about 6 months ago but they bolloxed it all up so I don't get it any more. Shame - its a goodun

nikki_d72
25-08-2009, 01:38 PM
Hiya, Did do quite a bit of etching at college but it's a long-winded, messy and quite dangerous affair (nitric acid, pretty obnoxious). Basically you have to cover the back and edges of the piece of brass with a "stop" varnish (black and goopy), let it dry, then gently warm the piece up an apply a stop wax to the front. It dries as soon as it cools. Then you simply scratch through the wax to make your design. Then comes the dodgy bit - the piece has to be immersed in nitric acid for enough time for the metal to be eaten away where there is no "stop", to your desired depth. The problem is that the acid is extremely dangerous, as are it's fumes so needs to be ideally done in a fume cabinet with full protective clothing, cloves goggles, the lot. Then theres the issue of staorage, COSHH regulations etc.

If its just for PMC (which I've no experience of) could you use something else to make your inpression in? I'm thinking maybe plaster of paris or something that you could either "cast" the impression in (you could use real objects then also - plant fragemnts, feathers etc) or just cast it in a block and the carve away to get your texture/image, whatever. Would this work? Would the clay be soft enough to be rolled over the impression on the plaster and then removed to take the impression? You could put a stretched layer of clingfilm in between the clay and the mold, to prevent contamination (thinking of my daughter's clay molding set here!)
Apologies if I'm talking garbage here as I've never used the clay so don't know how soft it is or even what it looks like.

If you want to get any more info on etching, drop me a line and I'll search the dark reccesses of my mind for any other details I can remember.

Cheers!!

Nikki

MuranoSilver
25-08-2009, 01:42 PM
If it's for PMC you could also use photo-polymer plates OR for one-offs
do water etching directly onto the piece ;)
(wather etching is when you apply the stop to the dry clay then use a soft sponge to wash out layers of the clay)

I prefer plate making though as I can use the photopolymer plates to replicate the designs
Nic x

nikki_d72
25-08-2009, 01:49 PM
P.S. If you do go down the etching route, it's quite useful for making steel impression plates, to use through the mills directly onto annealed silver sheet. You can also do this with other things - we used to use heavy watercolour paper, it gives a really nice subtle rippled effect, or rough grade sandpaper, just meke sure you clean your mills well after or you'll get dints in the next thing you roll.

Also, you can sandwich things between plain steel sheets, and a piece of silver sheet and roll to impress - ie little wire designs (in harder metal than your using, so brass etc) or anything hard enough to go through without breaking that would look nice as an impression. The bits you put through will fall away once you've taken the plates off, leaving you with the indent of it's shape.

Just watch how tight you wind down the rollers, if too tight it can leave the impression of the plate on the steel of the rollers and require skinning. Leave enough extra room around your steel plates, before the silver sheet inside starts so you can inset it into the gap of the rollers THEN wind down to fit, thus avoiding the above costly problem.

Di Sandland
25-08-2009, 04:21 PM
OMG guys, there is soooo much I want to do.