How long does torch firing take?
Original PMC must be fired for two hours to achieve full strength. PMC+ and PMC3 are both formulated to achieve full strength after only a few minutes of firing. Scientists might note that there is a trace improvement in strength as firing time is increased, but artists will understand that the recommended firing times are all that is needed. The best way to increase strength is not longer firing but making the piece thicker.

As a convenience, here are those recommended times:

PMC+	1650° F for at least 10 minutes OR 1560° F for at least 20 minutes OR 1470° F for at least 30 minutes
PMC3	1650° F for 3 minutes OR 1290° F for at least 10 minutes OR 1200° F for at least 210 minutes OR 1110° F for at least 45 minutes

What matters more in making PMC strong, the version or the way it is fired?
This sounds like a trick question. When each material is fired at optimum conditions, PMC3 is slightly stronger than the other versions. When fired at a low temperature or for an insufficient time, PMC3 would be weaker than PMC+ fired at full schedule. It's impossible to say which factor, time or temp, is most important. Instead we could say that falling short in either will adversely affect the PMC. And the greater the gap between ideal and actual, the more disappointed you will be.

Can I attach to already-fired pieces of PMC together?
Can I add a piece of newly modeled, unfired PMC onto a piece that has already been fired?
Yes. When adding fresh PMC to bond with metal that is already hard, you should extend the firing time to at least double the normal schedule. This allows the silver particles from one to penetrate into each other. Extend the time, but not the temp. You can go up to 1650oF (900C) safely, but no higher.

What is the best material to support round or curved pieces while firing?
Alumina hydrate is a white powder that is used by potters to make kiln wash. You can buy it at a ceramic supply. Because it is a bit hard to track down, I've taken to using vermiculite. This is the tan-colored lightweight material used for insulation and in potting plants. It is available from nursery suppliers, garden stores, and many hardware stores. The material is actually mica, a naturally occurring mineral, in this case, expanded. It can be used indefinitely. In the first firing you might see a small amount of smoke, but this is of no concern--probably bits of grass and other organic matter that is in the mix by accident. I have also had good luck using a kitty litter that is described on the package as "100% natural clay."

Can I use the pyrometric cones that potters use to gauge the temperature inside my kiln?
I've been told that pyrometric cones are not appropriate for measuring the relatively short firing times of PMC. Apparently they measure "heat work," the accumulated energy of time and temp, which is critical to ceramics but less relevant to metals.

I have an older kiln without a pyrometer.
Can I use this to fire PMC?
The potential problems with an older kiln are the possibility that it won't get hot enough, and (worse) the possibility that it will spike, or overheat rapidly, which could melt your PMC. My recommended way to use this kiln is this: Use either PMC+ or PMC3, both of which can be completely fired in ten minutes as opposed to the two hours for original PMC. These materials that will shorten the time at risk.

How can I test the temperature of my kiln if I don't have a pyrometer?
Make a rod of PMC+ or PMC3, roughly the size of a small wooden match. Allow it to dry, preferably overnight. Turn the kiln on, and allow it to heat to the point where the interior glows red. Set the PMC rod onto a tile or soldering pad and place it in the kiln. This will feel like putting a tray of cookies into a preheated oven. Keep an eye on the interior, either through a peephole or by keeping the door cracked open. Don't stare for an extended time--just peek every few minutes. You'll see the PMC smoke, flame briefly, then become red. This is difficult to see because the kiln itself is red; dark glasses will help. If you were doing this a lot or for long periods of time, you would wear safety lenses, but for this experiment they are not necessary.
    Allow the PMC to glow red for about ten minutes (or 3 minutes for PMC3). As you watch, be on the alert for a silvery, mercury-like sheen on the surface. This indicates that the silver is starting to melt and you'll want to quickly pull the door open to reduce the heat. At this moment you know the temperature of the kiln chamber--it is exactly 1760°F. I'd recommend doing this exercise a couple times with a short rod of PMC. If it fires properly, you should be able to gently bend the rod into an arc. I'd even encourage you to take a piece all the way into the melting zone, just so you know what it looks like.

Can I fire findings like pin backs in place?
Yes, it is possible to attach findings by fusing them into the PMC, though this is not my recommended procedure. Let me explain it, then offer an alternative. In an oxygen-free environment, we could put a metal component into PMC and it would fuse together easily. In reality, you should always combine the fusing (i.e., melting-together bond) with a mechanical joint. Paint or smear PMC over the edges of a piece so that it grabs onto it, just like your curled fingers grab onto a thing when you pick it up. This is easy to accomplish with some pieces, but difficult with others. That's one of the drawbacks.
    Nickel and sterling will both become severely oxidized during the firing process, leaving them cloaked in a tenacious black layer that can only be removed by sanding. That's another drawback. If you are using sterling elements, you cannot heat above 1400 degrees F. One of the advantages of PMC3 is that it can be fired below this temperature.
    My recommendation is to learn to solder. It's not difficult--in fact it's much easier than the steps I just described. It can be done with a $15 butane torch. Like anything worth knowing, it takes a little practice, but once you get it, you can attach bezel cups, pin findings, bails, and various parts with ease. Firing parts together takes at least an hour at temperature, so the process is not only tedious but time-consuming. Once you get the hang of it, you can solder parts together in only a minute or two. Because of the short time in the heat, the parts don't get nearly as black, so clean up much quicker.

Can I fire PMC with a hot air gun?
The invention of PMC3 made it possible to fire with a torch, or even, in a pinch, a hot air gun. I mentioned this because thousands of people already own air guns. The intention was, "If you have a hot air gun and you really want to try this out on the cheap, even that can do the job."
    If you are purchasing something just for this purpose, I strongly encourage you to go a slightly different route and buy an inexpensive torch. The advantage of a torch is that it is faster, easier to read temperatures and more versatile because it can also be used to solder if you choose to go that far. At many hardware stores you can buy a small butane torch that will work nicely, and costs the same or less than a hot air gun.

Is there anything to be done with scraps of fired PMC work that I don't want anymore?
Fired PMC is .999 pure silver, a valuable material that can be sold to jewelers or refiners. In the case of the latter, there is sometimes a minimum. Whatever you do, don't throw it out! If it's really in your way, let me give you my address.