Polytek PlatSil FS-20 Fast-Setting Silicone Rubber, 80 lb Kit

Description

PlatSil FS-20 silicone rubber is a two-part, platinum-catalyzed liquid molding material for fast-turnaround molds and cast parts. The system mixes 1A:1B by weight or volume, pours at low viscosity, and cures to a milky white A20 rubber. This SKU is the 80 lb kit for professional mold shops and production teams that need more material than a small trial or bench package.

Where It Is Used

FS-20 is suited to poured molds, rapid mold duplication, prop and scenic fabrication, model making, and other professional casting workflows where a short demold cycle can improve throughput. Its liquid consistency can flow around detailed models when the mold box and vent path are planned correctly. Polytek also notes that the material can be thickened for brush-on work, but any thickener changes handling and should be evaluated against the current technical guidance.

Platinum-cured silicone requires careful material compatibility. Sulfur-bearing clay, amines, tin compounds, some paints, cured polyester resin, and certain silicone rubbers may inhibit the surface cure. Run a small test on the actual model, release system, paint, and tooling materials before committing a large mixed batch. Clean containers and tools also help prevent cross-contamination from other rubber systems.

Mixing and Cure Planning

Bring both components and the work area to the conditions stated in the current technical bulletin before mixing. Measure equal amounts of Parts A and B, then mix thoroughly while scraping the sides and bottom of the container. The published pour time is about 8 minutes, with demold at about 25 minutes at 73 F. Higher temperatures shorten both windows, so prepare the mold, tools, and pour path before combining the components.

The mixed viscosity is 3,800 cP, supporting pourable processing around detail and into prepared mold cavities. Heat can accelerate cure, but temperature should be controlled rather than estimated. Keep batch size, ambient conditions, model temperature, and the available working time in view so the material can be mixed and placed before it begins to set.

For an 80 lb kit, stage the pour as a production operation rather than an improvised bench mix. Confirm the required mold volume, container capacity, mixing access, lifting plan, and path from the mixing station to the mold. Large masses can behave differently from small test cups because working temperature and handling time are harder to control. A qualified small-scale test should verify release, cure, surface finish, and model compatibility before the full batch is committed. Document the test conditions for repeatable production setup.

PlatSil FS-20 Silicone Rubber Specifications

For related mold-making systems, browse Chemical Concepts molding materials. Review the current technical bulletin and application resources from Polytek before mixing production quantities.

Need Help?

Need help planning kit size, mold volume, or cure-compatibility testing? Call (800) 220-1966 or email [email protected].