September 7th, 2006
Both the masking techniques we tried for the silver etching look promising, although I want to try them again with a narrower line before actually etching. Fabulous! In general, one's risking losing detail, so being able to go for more detail is great.
I got a casting back from the casters, but they didn't "patinate" it as we had requested. On the plus side, they didn't charge us for doing it, either... still, that means I have to do it, and I don't currently have the materials for is, since the thing in 14k white gold, and it really doesn't oxidize. I'll order the materials I need tomorrow, and meanwhile can get the jump ring soldered onto it so that it will hang properly when on a chain.
The bail and the loop are now on my plique smiley. In addition, I've wired the bail together to minimize the risk of things slipping if it gets past the melting point of hard solder in the enameling process. Now for the depletion gilding...
I fired the cloisonne smiley again, and think I'll just go with this one. At least I'll start finishing the enamel, and then see. I think it's OK- not utterly splendidly fabulous, but OK, and quite suitable for the purpose.
I riveted the trillium pin together with a tube, and drilled a hole and fitted a wire for the stabilizing rivet. I'll get that seated, then get the stone added and that one can get photographed and go up on my site and/or Etsy.
As usual, other bits were accomplished, but that's the gist.
|Date:||September 8th, 2006 06:32 am (UTC)|| |
Do you etch the silver with nitric acid?
Yes- that's what I learned, so that's what I'm going to do. It's pretty dilute- 4 parts water to 1 part concentrated nitric, if my memory serves me, and then electically assisted.
At some point I'll probably try the ferric nitrate, but I have the acid so that's what I'm going to use now. I'd originally gotten it for depletion gilding gold, which I still mean to do someday...
|Date:||September 9th, 2006 09:19 am (UTC)|| |
Oh I have used it on silver too. What I didn't like about it (for copper also) is that as it "eats" in all directions, the lines always become blurry. But I guess it doesn't matter depending on your design, if it doesn't have very clear lines. I certainly don't like it for champlevé, but for basse-taille you can get very interesting results.
I have never tried the ferric chloride (what is this nitrate you speak of, a similar thing for silver?) with silver, I think I was told in school it didn't work?
You can't do depletion gilding of gold in sulphuric acid, like regular silver?
I use the nitric all the time for the cleaning of copper, it is the acid I use the most (it still lasts ages anyway)
I've gotten pretty crisp lines with the nitric acid, as long as it was dilute and electrically-assisted. I don't go deep enough for champleve, though. I'm hoping I can replicate the crispness, becvause there's a commission I have for which etching is really the only practical choice, and I don't want the lines too blurry! A bit blurred is OK; the art's hand-drawn anyway.
The ferric nitrate is similar to the ferric chloride, but for silver. Ferric chloride doesn't work on silver- that's true.
If I depletion gild gold in just the sulphuric, it'll get rid of the copper but still leave any silver in the alloy, potentially giving a more green-gold skin. And I hate and loathe green gold. :) I did get a really nice fine gold skin on some rose gold- which I was trying to avoid that time!- but for this stuff I have standard yellow alloys and I know they have both copper and silver, and I want to get rid of both on the surface.
Thanks for the tip about using the nitric to clean copper! That will be a good use for the stuff I make up for the etching after I'm through etching. :)
|Date:||September 9th, 2006 04:36 pm (UTC)|| |
Electrically assisted? you mean heated? I have no clue what else could that mean!
Nice to know that about the ferric nitrate, I didn't have a clue and this will be useful I hope, thanks!
Oh I didn't think of the silver in the alloy, now it certainly makes sense :) If you want to use it for cleaning copper, you can use it pretty diluted, one part for eight or ten water is normally enough, and no need to heat. When it gets very blue it is time to replace as it starts working very slowly. And this you probably already know, but better safe than sorry: don't use the same nitric for silver and copper, as something of the copper deposits in the silver if I remember well, but we were very warned about this in class.
For "electrically assisted" I mean running electricity through it. We used a battery in class, but J got some sort of eletrical thingie for anodizing titanium, which I believe can be used for silver etching as well. If I can't get that to work, I'll get a battery. We used those really big, cubical ones; I forget the power. And we used a piece of titanium sheet on a titanium wire on one side, and titanium wire in a hole drilled in the silver on the other. It did produce a noxious gas, so I'm going to do it outside.
What I figured I'd do is do the silver etching I need to do (including any my students want to try), then use the somewhat-depleted soluton for cleaning copper until it gets too blue.
I must admit to being curious about not using it on copper after silver (though I'm not planning on doing so!). I mean, the solution definitely got blue just from etching sterling, because of all the copper in it. I can see using it on copper getting it dirty a lot faster, but I'm wondering why it would make a qualitative rather than a quantitative difference. Kind of like with pickle- at the craft center we had 2 pickle pots, one for copper and its alloys, and the othr for silver and gold- but that was just because the copper one got dirty so fast! In my studio I use the same pickle for everything, but I do keep it clean (and also use it very dilute). I'll have to research the nitric-and-copper issue!
|Date:||September 9th, 2006 06:02 pm (UTC)|| |
Yeah I am afraid I don't really remember why it is that the silver cannot be cleaned in the nitric used for copper. What I remember is the nitric getting whitish and milky from the silver, not transparent blue as from the copper. Or am I so off? I haven't used nitric for silver in ages, we used it in enamelling class because we only had nitric, (ans some people made a visit to the sulphuric in the jewellery class nearby) but when I am in my own, or in workshops I have worked, we only use sulphuric to clean silver, which doesn't eat to it and works better.
Maybe the problem is only if you are going to enamel the silver afterwards (we where told against it only in enamelling class), and the deposit from the copper nitric makes things go wrong at some point. Certainly the more copper there is in the silver the worse the enamelling goes...
I am definitely curious about what was going on with the silver vs. the copper in the nitric!
We etched both fine and sterlign silver in the nitric, and the solution remained clear and got increasingly blue. Hmm. Whitish and milky sounds like something was precipitating out; I wonder what it was? Silver nitrate is really soluble, but most silver compounds aren't, if I remember my chemistry correctly.
Now, we never put copper in that nitric acid solution, because we had both sulphuric pickle and ferric chloride etchant for it. But we did etch the silver with no milkiness- in fact, since neutralizing the acid was such a pain to do, a cupboard in the craft centr studio was about a quarter full of jars of the stuff that people had put away rather than neutralizing and discarding! And they were ALL clear and blue.
Very weird and interesting!!!!
Now, it might well be that this is one of the significant differences between doing the etching with the electrical assist, and doing it without. How long did you usually etch the pieces? We tended to go 20 min. to an hour, depending on how deep we wanted it and how "used up" the acid was.
|Date:||September 10th, 2006 09:00 am (UTC)|| |
Well, I certainly don't remember how long I etched the pieces, that was many years ago, and I don't know either how concentrated the acid was, so really no clue. But I still have this memory of the acid being milkish and white, because it was strange to me, being used to nitric for copper and sulphuric for silver, both going blue. I have never studied any chemistry so, really I don't have a clue what that was.
It sounds like something was precipitating out, so some sort of non-dissolving compound was being made in the etching process. This might be why we used the electricity- it would force the reaction in a certain way, probably one that would not otherwise had happened. I wish I were not so many years away from my chemistry knowledge, or I'm sure it would be more clear to me!
I think the sulphuric turns blue because of the copper in sterling. Or did it also do that if you used only fine silver in it? I know that when the silver pickle is pretty blue, you can force a copper plating on stuff- whether or not you want to!- by putting it in the dirty pickle with some steel...
|Date:||September 11th, 2006 07:22 pm (UTC)|| |
Hmh, I have never used fine silver, unfortunately, so I don't know.
Yeah I had that copper plating in not-so-good steel tweezers, they turned pink on the tips, hahah.