Heating automotive clay

I’ve just bought some automotive clay for my thesis (wax stuff) that you need to heat up to work with. I’ve worked with similar stuff at GM Holden, however they had big clay ovens which made that job much easier.

I need to put my large slabs down, so I can’t just use a hot air gun (or can I?). Ideally I’ll have my block of clay gummy so I can put it straight onto my model.

Does anyone have any makeshift options that work well? I pulled out an old electric oven that I could use to ‘cook’ my clay for a couple of hours, and hopefully it doesn’t burn it. I’m thinking if an electric space heater pointed into a cardboard box will also be good enough.

Space heater pointed at a cardboard box is just asking for you to burn your house down.

I know some people who’ve used a microwave on low, but you need to be very careful with the timing so that you don’t get molten clay all over you.

I dunno what clay you have purchased.
As mentioned, I have put it in the microwave to soften it then start kneading it. Try 10 second intervals, be careful the center can get real hot. I also have used hot water in a container, you just gotta work fast. Heat lamps are good after you rough it out.
Good luck!

Adjustable table lamp with a hot bulb.

Household convection oven 60 degrees C. Hard to imagine a microwave working to maintain the correct softness.

Dont micro it… I did, worked fine until it got a bit too warm. There was some kind of particles in it that expanded and looked like green rice crispies. Doesnt look to well with those pimples on the surface.

I have only used the micro in a pinch. Yes, a microwaves is a pretty crappy way to heat the clay up, agreed.

Convection oven is the best thing… if you got one. They had large ovens where I used to work, they are the same ovens used to cure urethane and cast plastics. I would not put clay in my kitchen oven, so now at home I use a computer controlled kiln I have for ceramics.

It even works great for making pizza on a stone :smiley:

In school our prof. brought a microwave for us to use to heat up our food during all-nighters, some of us used it for the clay. Needless to say he wasn’t very pleased. :laughing:

any suggestions on how to gauge how much microwaving is needed, and how to do it? I figured low power… but any other hints?

Working with clay is about maintaining a constant temperature / softness of the base stock of clay. Microwaves are not going to do that. Electric oven or heated box is the way.

Yeah I figured that… I have a small pie oven keeping the heat, however its taking ages to heat them up.

I just found out that there are small iron filings inside my clay… so I can’t microwave it

When you heat it, make sure to use a thermometer in the oven. I’ve had experiences with the clay overheating and crystallizing. Depending on the clay, you may get a wider temperature tolerance, but try to keep the temp dead on.

styro-foam cooler + heat lamp = hot box.

Here’s a similar solution with pictures:

Ofcourse with any of these solutions you’ll have to carefully monitor temperatures, and never leave them on without being present.

I would NEVER use any appliance used for cooking food to warm clay. Gross.

cut it into slices twice the size of bread slice, put on large metal pizza tray, then placed 4 heat-lamps about 24" away.

I used a foiled lined plywood box, until I found an old commercial bun warmer … used ones are everywhere, and can usually be had for $100 or so. Mine had two drawers with individual heat control. And temp control is important; low and slow when it comes to heating. Chavant clay will separate if it is overheated, leaving and “dry” base behind (per bcpid - crystallized).