Mold material that increases size of original

I recently read somewhere that there is a material that can be used
to make molds that will increase the size of the original by 60% if
water is added to it. I cannot find the now. Does
anyone know what company is selling this compound?

Samara

Samara, This may be the company you’re looking for:
Polyurethane Coatings & Resins That Endure | Chemline. Look under “expanding
urethane”. I haven’t tried the material or the company, but had
bookmarked it, just in case…

Best Wishes,
Anne M. Kelly