Prometheus Clay’s attractive feature is that you can torch fire it. One of the least desirable things about working with non-precious metal clay is the need to fire it in charcoal or a similar medium to keep the surface from oxidizing during the firing process. You don’t have this problem with fine silver because it does not contain the copper that causes the oxidization. (I have not worked with Sterling Silver clay and am not familiar with how it is fired)
The Hadar’s clay that I worked with needed two step firing. First, you had to bring the clay to a certain temperature to burn off the binder material in the clay and then you have to let the kiln cool to room temperature. Only then could you start refiring the clay to the sintering point where the remaining materials would fuse and give you metal. Needless to say, this takes a long time. It’s really a two-day job.
My experience with torch firing the Prometheus clay was mixed. It is not as easy is it looks but with practice, I think it is viable alternative to kiln-fired metal clay. I am confining my experiments to Bronze clay because I think it’s rich looking and attractive. I work with the copper i metal sheet and wire and really like it but I do not think that the results you can achieve with copper clay are worth the time and effort. That is just a personal opinion.
. The Prometheus Clay was workable out of the package although conditioning is recommended. For a video showing how to condition the clay, press here. I formed a pendant shape and two smaller shapes to suspend on ear wires for earrings
I used rubber stamps to impress the designs into the clay and then let the pieces air dry for a couple of days.
They recommend you torch fire the dried clay on a screen for seven minutes which you start counting after you have burned off the binder. Here I am torch firing two earring pieces. I learned the process after watching this video. I am using an EZ Torch.
At the conclusion of the firing, you drop the pieces into water and the oxidation starts to peel off. You have to clean off the remaining oxidation by hand using a brass brush.
I was able to clean off the oxidation but I lost the spiral pattern I had impressed into the wet clay initially. See top picture. The pieces withstood hammering and a trip through the rolling mill (which I used to try to put a new pattern on the metal) but the latter revealed that the pieces were not completely sintered. You can tell from looking at the edges in the above photograph.
I don’t have any process pictures for the pendant, but it turned out much better. While it was larger in diameter (the size of a large guitar pick) than the two earring pieces (which were about the size of a dime), it was thinner.
After the initial cleanup, I decided to use a swage block to give the pendant more of a shield shape.
The pendant withstood the hammering and I achieved a shield shape without any trouble.
The pendant after polishing and finishing. I did notice minor layer separations on the sides of the pendant but I was able to tap these together with a hammer and and smooth them out with a file. I would guess that the metal was not completely sintered in those spots.
What’s my verdict? Overall, I like Prometheus Clay. Torch firing metal clay is not as easy as it looks. You don’t want to under or over heat and you need to keep the torch moving. It is easier to maintain a consistent temperature in a kiln. I suspect that the problem with the earring pieces is that they were not totally 100% bone dry. The pendant was completely dry and sintered more completely. The oxidization was fairly easy to clean off and the torch firing method is quicker than the kiln firing I’m used to. On the other hand, the designs I stamped into the clay did not remain as sharp as I would have liked. I don’t know whether that is a by-product of the torch firing process or my inexperience.
You can kiln fire Prometheus clay too. I might explore that in the future but for now, I will keep experimenting with the torch firing. You can purchase Prometheus Clay from Clayrevolution.com. The site runs sales from time to time and contains a lot of useful information on working with metal clay.