Our moulds
I'm very sorry you had such a difficult time with our moulds-especially the first time you used them. There are some tips which should produce much greater results.
First, regular plaster of paris (POP) is very brittle, shrinks substantially on drying, and is generally not recommended (although some high-grade types are OK). Instead, try a harder plaster such as Herculite #2 or Hydrocal. You can also use any number of harder, denser, dental plasters too. Dental plasters shrink less and are very hard.
Second, allow a few hours for your castings to dry-the longer the better. I allow mine to dry for 12-18 hours or more. Once completely dry, the pieces can be removed much, much more easily. A common mistake is removing them too soon. Although you can remove them in about an hour, the castings are soft and delicate. Allowing them to "dry up" lets them be at their strongest.
Third, if you are still having trouble removing the pieces, put a small amount of dishwashing liquid in each cavity before you add your plaster. This will help with de-moulding.
Fourth, you mentioned that your pieces are different sizes. Could you elaborate on that? If you are using POP or some other plaster that shrinks, it may appear as though the pieces are different sizes. They are actually all carved to the same dimensions so there will not be a discrepency in their size. Please check the manufacturer's shrinkage claims for your plaster.
Finally, if you are still unsatisfied, please contact me. Linka World has a very generous returns policy. The last thing I want is for anyone to be unhappy because of my products. I think we do a fair job at describing our moulds and the steps involved in casting with Plaster on our Website. Nevertheless, working with plaster (or resin) does involve some extra work that a lot of folks are not prepared for. Please let me know if I can be of further assistance.
Sincerely,
- Richard Purdy
Linka World