Air dry clay, or paper clay: IOD paper clay is an air dry medium, and one of our favorites. Like most paper pulp based air dry clays, some shrinking, warping, and cracking is inherent. We like these qualities for a distressed, authentically vintage look. Our favorite way to apply moulded pieces is to remove them from the mould while still moist, and adhere to the surface with the appropriate glue so it conforms well. For vertical surfaces, use a piece of low tack tape to hold it in place so it doesn’t slide.
Casting resins: There are some great pourable resins available. These have completely different qualities than the paper clay. There is no shrinking or warping, and the castings are more consistent. Depending on the project, these qualities can be helpful. If you need to conform them to a curved surface, this can be done if removed from the mould before it’s completely hardened.
On releases: We find that most of the time a release is not necessary and the casting will come out without the use of a release, however, if you are having trouble with the material sticking (more common with clays than resins), a light dusting of simple cornstarch or arrowroot is a great choice.