Actually there is no right way, but I have seen a number of articles on baking Polymer Clay and thought this information could be useful to some of us here.
I would suggest buying a dedicated toaster oven. Go to the local resale you might have some luck, scrape the crumb tray off or even throw it away, or go buy a new one for your kitchen and take the old one to the workroom.
I'm putting the Manufacturer specifications at the end because we already know that information even thought it might not be the best way.
Regardless of what method you use practice proper safety precautions. Never use tools or dishes for food after using them for polymer clay and be careful handling hot items.
Clean your oven thoroughly after baking polymer clay if it dedicated to polymer clay use or if clay wasn't baked in a sealed container like a roasting bag.
Ramp baking is a technique for gradually baking polymer clay to achieve a hard but minimally darkened result.
Starting at a low temperature of around 175-200° F bake for 30 minutes, increase the temperature by 15-30° and bake for 20 minutes, continue increasing the temperature by 15-30° and baking for 20 minutes after each increase until the temperature reaches the manufacturer recommended temperature. Bake at the recommended temperature for 30 minutes. Allow the piece to cool completely in the oven before moving.
This method requires careful monitoring to make sure the piece doesn't start darkening excessively. Some oven temperatures can spike significantly, always use a separate oven thermometer to monitor temperature.
Under baking is a technique used to try and prevent the darkening that some clays experience. It involves baking under the recommended temperature, usually at around 200° F, for an extended period of time often 1-3 hours depending on the thickness of the clay.
The main risk of under baking is a polymer clay piece which is weak or degrades over time due to the clay not being fully cured.
Over baking is a form of ramp baking used by some sculptors like Casey Love usually with super sculpey to get a very hard result with no cracks. Because the technique causes significant darkening of the clay it's used for sculptures that are to be molded for casting or painted.
Start at 225 and leave the sculpt for an hour, raise the temp to 250 for another hour, raise the temp again to 275 for 2- 3 hours or until the Super Sculpey has turned a dark caramel or even as dark as a reddish brown brick color. Shut off the oven and leave the sculpt to completely cool down before removing the sculpture. If you are baking a rather thick sculpture use the same method above but raise the temperature slower and in smaller increments.
What the makers of polymer clay brands recommend.
- Super Sculpey should be cured in a preheated 275° F (130° C) oven for 15 minutes per quarter inch of thickness. DO NOT MICROWAVE. For example, a piece of ½" thickness would be cured for 30 minutes. The layering method is recommended for lager pieces of construction.
- Premo! Sculpey should be cured at 275° F (130° C) in a preheated oven for 30 minutes per quarter inch of thickness. DO NOT MICROWAVE. Once cured, the colors intensify and deepen.
- Sculpey III should be cured in a preheated 275° F (130° C) oven for 15 minutes per quarter inch of thickness. DO NOT MICROWAVE. If you're unsure whether your piece is adequately cured, try pressing the tip of a fingernail into the bottom of your piece after it has cooled; it will leave a mark but will not actually enter the clay.
- Any home oven is suitable for hardening FIMO. Preheat the oven at 110°C/230°F. Place the FIMO model on an aluminum sheet, and plate or glass sheet and put it in the oven. Depending on the size of the model and the thickness of the walls, the hardening process takes approx. 20-30 minutes. FIMO reaches maximum hardness when completely cool.
- Cured at 275° F (130° C), this clay can be used in a household oven. For every 1/4 inch of thickness, it should be cured for 10 minutes.
- Kato Polyclay, oven hardening polymer clay, bakes at 300° F (150° C). However, it can also be cured at 275° F (135° C) with good results and has been approved to cure at 350° F by our toxicologist, however caution should be taken when curing at that temperature, time should be limited to 10 minutes as you will run the risk of discoloration. You should never exceed 365° F. In prior laboratory testing, it has been determined that tensile strength increases
hopefully this can help some of us out in the curing process, here is a link to the original article, I have re-posted excerpts of, with all the glorious ads
Techniques for Curing Polymer Clay
*added july 12th by Franz Bolo*
Originally Posted by Pzak
I bake at 220 F. First, you need to make sure the oven is at temperature before you put the piece in. Most ovens ramp up fast, and unless it is a convection oven you will burn thin pieces.
Make sure your armature is solid and can hold the sculpt without flexing. When polymer clays bake, they become quite rubbery and will crumble easily. Also, parts that have been cooked with become rubbery as well so don't count on them to support your piece.
And if you have used CA glue, it can soften at this temperature and loose its adhesive properties. I have had the thin CA glue actually go back into solution and glued my fingers together when I wiped away what I thought was water on the piece.
If you have very small parts like horns or fingers, you can also cover them with foil to reduce burning them.
Don't get too stressed about discoloration. I accidentally left a piece in the oven over night. It turned black but after priming, you couldn't tell there was a problem. Actually, when you are complete with the piece, I would recommend cooking it for a long time until it turns almost caramel color (regular SS, not the sculptors gray). It will be very hard and durable. Cooking to short can make the piece crumbly, but easier to sand, so keep that in mind.
Lastly, I would suggest you turn the oven off and let it cool before trying to move it. That's when most breakage occurs.
But if you want to part the piece out, you can make perfect cuts when it is hot with an exacto blade an it is like cutting silicone. This works great if you have already cut the armature an you are on the final bake.
BTW, I usually bake my piece many times before they are complete.
I forgot to add, be careful using a heat gun. If you get it too hot too fast you will cause it to blister and you will have to dig them out and fill it back in to fix it. Sanding won't fix the problem because it they will resurface if you bake it again. I wave my heat gun back and forth while heating to avoid over heating the surface.