Check out these new trays I have. I got them free. They are heavy gage aluminum baking trays. The outside measure about 13"x 18". In the past I've used lots of RubberMaid lids from storage containers which worked well in the sense that they would never damage anything that was laid on them. But those lids have no support if needing to move the parts. With these I can pick the whole tray, parts and all, and move them.