Even better, we can show you a site that will do it for you (and teach you while it does)! Just follow the link below and click on the shape that closely approximates your form. Then enter the dimensions, and select the type of plaster that you’re using (USG #1... Yes. We offer a large selection of Mason Stains® both in pre-measured quarter-pound bags and in larger quantities. Yes. We sell 50# bags of many Raw Materials and Chemicals. We will also weigh out smaller quantities of most of those materials on an as-needed basis. Most materials are weighed out by the one pound or quarter-pound increment depending on the cost and purpose of the... Yes. We sell pottery plaster in 50# bags.