I just got back from a huge bead show where Art Clay had a large booth and taught make and takes, demos and gave people a lot of information. During the course of the show, I had repeated complaints from people saying that there was one particular teacher at the show who was telling people that you should NEVER torch fire metal clay. The pieces weren’t strong enough, they would break, etc., etc. Worse, then we had to defend our torch method and refute the previous info.
I’ve been working with Art Clay for 15 years, and I’ve heard ALL kinds of urban legends, outright misinformation and quite a few things that surprised and, actually, pissed me off. But I’m getting REALLY TIRED of people spouting their own version of scientific reality that has little or no relationship to the truth.
First, there are several instructors out there that swear on a stack of Bibles that the only way to fire silver clay is to fire it at 1600-1650 F. for 2 hours. That’s Art Clay, PMC plus, PMC 3, whatever. It’s like, if 1650 for 10 minutes is good, then 2 hours MUST be better, even though NEITHER silver clay manufacturer supports that firing schedule.
Secondly, there’s the torch debate. Again, neither silver clay manufacturer has EVER stated that torch firing is NOT a method that sinters their products.
Before I address both of the above urban legends, I want to say that if you use a technique that is contrary to the manufacturers’ directions, and it works for you, and you feel strongly about it, then MAKE IT YOUR OPINION, NOT FACT!! How confusing must it be for newbies who are trying to decide if getting into metal clay is for them, if someone they respect is telling them one thing, and other people they respect are telling them another??!! If you don’t like to torch fire, you don’t teach torch firing, and don’t think it makes a strong sinter, then begin your statement with, “In my opinion…” But to say, “Never torch fire because it doesn’t work and you should NEVER do it!” just isn’t correct! Period!
If you go onto either the Mitsubishi Materials Corporation or Aida Chemical Industries sites you will find information on firing silver clay. Mitsubishi actually mentions stovetop firing or firing with a bunsen burner!! Rio Grande, Mitsubishi’s major distributor, sells torch kits and PMC Connection has always pushed the Hot Pot, which I personally, IN MY OPINION, think is a waste of time. Aida has always promoted firing Art Clay with a torch. And let’s examine that for a minute.
Most of the torches used to fire silver clay, whether butane, MAPP or other, have a top temp of around 2000 F. The sintering temperature for silver clay is between 1110-1200 F. and 1600-1650 F. When we use the torch, we can visually confirm that we are at the proper sintering temperature by the salmon or peach-color of the piece, when seen in dimmed light. Then we are told to hold that temperature for whatever time. For Art Clay, we have always taught between 2-3 minutes for 10 grams. PMC firing instructions are similar. Now, if the sintering temperature, as cued to us by the color of the metal, is between 1600-1650 F. and the top temp of the torch is around 2000 F. then wouldn’t you think the manufacturer would know what they are talking about when they give us instructions to torch the pieces?
I have been torching rings and other Art Clay items for 15 years and I have never had a ring break. Never. I have always followed the instructions and if I think I haven’t counted accurately, I overfire. No harm in that. Underfiring, on the other hand, is a set up for disaster and will produce an undersintered and, therefore, weak pieces prone to breaking.
Both companies that manufacture silver clay are owned by Japanese. In Japanese culture, failure is not looked upon kindly or as socially acceptable. So, logically, would either company put out instructions for a technique in firing their products that would result in a weak and potentially unfinished piece? Really?? Is the kiln a better method of firing? Absolutely. Does it produce stronger pieces when fired at the recommended time and the recommended temperature than torch firing? I think everyone believes so. But, I would rather torch fire a piece, knowing my sintering temperature is near the 1600-1650 F. mark, than kiln fire my piece at 1110-1200 F. for 30 minutes.
Which segues perfectly into the second urban legend. Firing at 1650 F. for 2 hours is the best way of firing. Where on earth did that come from? Does someone have an article or mention by EITHER manufacturer that lends credence to that? I have always thought that this believe stems from the original firing schedule for PMC Standard, which needed to be fired at 1650 F. for 2 hours. It shrank a lot, had a lot more binder, and it preceded PMC Plus and PMC 3, which fire for a lot less time. Maybe some of the PMC artists thought, well, if that was the firing method for Standard, then it must be used for all PMC versions. But, again, if that’s the case, why would the manufacturer say differently? One really, logically, has to assume that both Mitsubishi and Aida WANT their products to succeed.
Again, I’m not saying, don’t have an opinion, I’m saying, we have enough issues in the field of metal clay, trying to get people to try it and accept it, without the confusion of unsubstantiated claims that are meted out to students as coming from Above and sacrosanct.
If I’m incorrect, if someone has a directive from Mitsubishi to fire their clays at 1650 F. for 2 hours, I will be the first to apologize and alter my thinking. But I will stand by Aida Chemical Industries’ firing schedule for 1200 F. for 30 minutes to 1600 F. for 5 minutes, understanding that firing at 1200 F. should probably not be used on rings that take a lot of wear, but allows you to include glass and certain gemstones, and thereby allows increased creativity.
Actually, I do, myself, have an IMHO (in my humble opinion) statement. When I fire Art Clay silver in the kiln, I fire it for 10 minutes, even though Aida, in reformulating its clay some years ago, says you only have to fire for 5 minutes at 1600 F. Why? Because the old formula did and I am just in the habit of remembering 10 minutes. But it’s my opinion. If you read the instructions, it says 5 minutes, but I feel more comfortable at 10 minutes. Do I teach 10 minutes? Yep, but I typically say exactly what I say here.
If you want to fire your pieces at 1650 F. for 2 hours, or if you don’t want to torch fire because you think it’s not a good method, mazel tov. But don’t go around like Moses holding up the 10 Commandments making statements of fact that aren’t. If we have our own strong opinions about something, we should be able to be genuine and forthright enough to admit it . IMHO only, of course.