Can I use any gypsum plaster for FMG?

Article courtesy of Smooth-On, Inc.

While VF-812 will improve the properties of most gypsum plasters, FMG requires the use of alpha hemi-hydrate plasters formulated for a low water/gypsum ratio. Most commonly used in the US is Hydrocal® FGR-95 from USG, which is specially formulated for architectural ornamentation. Also used are Densite HL from Georgia Pacific and GRG XL from Allied Custom Gypsum.


This FAQ article is offered as a guideline and offers possible solutions to problems encountered during mold making and casting. No warranty is implied and it is up to the end user to determine suitability for any specific application. Always refer to the provided Technical Bulletins (TB) & Safety Data Sheets (SDS) before using any material. A small scale test is suggested to determine suitability of any recommendation before trying on a larger scale for any application.