In the winter of 2007-8, when I was first testing bronze clay for Bill Struve, I test fired various grades and sizes of diamonds with the bronze. I bought a group of diamonds from Rio Grande and fired them once by themselves in the following manner: I fired them with a load of bronze clay, at the schedule I was using at the time (250 per hour to 1525, then 3.5 hours), reasoning that if they survived through one firing cycle they would do fine a second time. I then set them as I would in PMC, and fired them a second time.
I now use the best quality diamonds (with the fewest inclusions) and have never had a problem.
Although pre-firing them is a good strategy, it does have potential problems: Imagine hunting through a bucket of sparkling carbon granules for teeny tiny sparkling diamonds. Impossible, and I lost several little diamonds before I solved the problem by making myself a little bronze box, with a friction-fit lid, that could be fired in carbon and recovered without spilling its precious cargo. There are certainly other ways you could contain those tiny stones (fine stainless steel mesh, etc) but I liked the idea of using the first box made in BRONZclay to fire the first diamonds fired in BRONZclay.
Seeing your work is both daunting and breathtaking. Thank you for your inspiration and gracious sharing.
ReplyDeletegloria c.
essenceofsilver.etsy.com
So diamonds can be fired in bronze clay! Thank you for sharing your finds and beautiful work. Even when my work doesn't "work", I enjoy looking at this site to see what is possible. Merci, Celie! You are a blessing.
ReplyDeleteYes diamonds can be fired in bronze clay! Thanks for your kind words!
ReplyDeleteYou are amazing! Thank you for sharing your beautiful work. You are truly an artist. I love looking at your jewelry.
ReplyDeleteWhy is pre-firing the diamonds a good strategy? I recently fired tiny, rough diamonds into my bronze (1560 F for 3 hours) and they came out fine. However, when I fired a few more of that same package of diamonds into my PMC3 (1650 for 10 minutes), they were completely gone when I pulled the pieces from the kiln! Whoops- glad they weren't any bigger.... I love the look, though, and will keep trying...
ReplyDeleteHi Nisa,
ReplyDeleteI pre-fire the diamonds to see if they'll survive the firing; if they survive once, they'll likely be okay the second time. I pre-fire only if I'm using a new source for diamonds. Now I use Rio top quality diamonds (I find it's important to use top quality diamonds because the inclusions in the cheaper ones can be a source of firing problems) and no longer pre-fire them because they have proven to be reliable.
Your diamonds survived the BC firing, but not the PMC firing, for two reasons: One, the BC is fired at a lower temp, and two, because BC is fired in carbon. The carbon seems to protect the diamonds.
I don't use diamonds in PMC3 because my understanding is that you need to keep the kiln temp under 1200F or so (to protect the diamonds) and for my purposes PMC is not strong enough when fired at that temperature.
You can fire diamonds into PMC PRO just fine, though. I've done that many times; because the PRO is fired at a lower temp (1400F), and in carbon, the diamonds come through the firing perfectly. The new clay is lovely to work with, carves beautifully, handles beautifully and I highly recommend it.
Beat regards,
Celie
Thank you so much for your insights Celie! Extremely helpful and deeply appreciated!
ReplyDeleteCheers,
Annie B
Thanks again for all your comments, and to Anonymous; It's good question, really, and you supplied the answer: Usually I do make and fire the PMC part of the piece (at 1650F) then I add the polymer clay and bake the whole piece at 275F to cure the polymer. Unless the two are mechanically joined (lock and key) I would then glue or rivet the two together.
ReplyDeleteHi Celie; I'm wondering- if 14kt gold melts at 1615 degrees, is it possible to use pieces/findings in PMC3 or if Pro is better because it fires at a lower temperature? What is the highest temp you'd take 14kt gold to in a kiln? Thanks!!!
ReplyDeleteHi There,
ReplyDeleteThank you for sharing the knowledgeable blog with us I hope that you will post many more blog with us:-
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