For items such as beads, and especially larger ones, we prefer to bake them immersed in a pan full of baking soda (sodium bicarbonate). Larger items can expand when heated and then contract as they cool. The expanding can sometimes cause surface cracks which at times can heal and close up as the item cools but these surface flaws can be extremely disappointing after working so hard on creating that perfect piece!
After several years of baking our beads in baking soda, we have not had a single item crack on us, provided we were not impatient and tried removing it from the pan before completely cooled.
Another reason for baking polymer clay pieces in the baking soda is to prevent darkening or discoloring such items that are white. We have to do this even more after learning from Donna Kato, of her recommendations to bake the Kato clay at an even higher temperature (340 F). (See their facebook page here.) We only bake at 325 but have noticed a stronger odor when cooking and some color shifting. However, we have found that baking them immersed in the baking soda has kept the colors more true.
So here are a few tips on baking with this method:
-- Use Baking soda (sodium bicarbonate) -- not Baking powder. Just look for the one that comes in the box (shown above) and is quite cheap.
-- It is best if you have a pan (or two like we have) dedicated just for the baking soda method. Yes, you can use this baking soda over and over again. Your pan will need a lid so the baking soda doesn't get all over the place and especially if you use a convection oven with a fan. You can use tin foil which works well. We did that for a while until I cut a piece of cardboard for a lid and covered it with tin foil. We kept the lid down tight while baking with some large binder clips.
I was out shopping one day and discovered a new idea which made things easier. These are pans for a toaster oven. There were the small broiler pans (like a small cookie sheet) and the deeper type roaster pan. We found the shallow pan fit inside the deeper one and made a perfect lid. It sat down so nice we don't even need the clips. We also have several of these so we can stack them and bake two pan fulls at a time.
-- And sometimes we just have a few beads to bake but not enough to fill a large pan so we have these smaller tins that have a lid and we can bake them along with our other items that don't require the baking soda.
-- For some items that just need a soft surface for support, they can be layed on top of the baking soda. If you want to prevent the colors from darkening or your beads from cracking then they need to be completely immersed. We have a container that we keep our excess baking soda in so our pieces can be carefully placed into the pan and then covered up.
So here are some pieces below showing the difference in baking with and without the baking soda. And yes! I discovered you can bake items that have been silk screened immersed in the baking soda. We gently wash them with soap and water to remove any baking soda and allow them to dry before giving them several coats of PYM11.
|Silk screened "Snaps" baked in baking soda|
|Silk screened "snaps" baked in baking soda|
And we also use the same type of pan / lid system when baking without the baking soda. We will place a small tile (for flat items) or quilt batting in the bottom and use the shallow pan as a lid. The pan sits in nicely or for more inside space it can be flipped upside down and held in place with the binder clips. This is a great way of "tenting" your work and also keeping any smells or odors from escaping while baking.