Fillers & additives

Fillers and additives: control the properties of your silicone or resin

A casting material straight from the container is a good starting point, rarely the end point. With the right filler or additive you make it lighter, thicker, faster, slower, softer or easier to sand – exactly what your mould or casting needs. In this category you will find the auxiliaries for silicone, epoxy, polyurethane and composites. Primers for adhesion are listed separately under Primers for silicone, release agents under Release agents.

Fillers: weight, volume and sandability

Hollow glass beads (microballoons) and Fillite ceramic microspheres reduce density and shrinkage and make a resin easy to sand: ideal for fillers, lightweight laminates and large castings. Talc (Finntalc M-30-SQ) gives a matte, scratch-resistant finish and better slip in coatings and plastics.

Thixotropic agents: against sagging

Fumed silica makes almost any resin or silicone non-sag, so you can apply it vertically without it running off. A small dose has a big effect; stir in last and disperse gently. For silicone there are dedicated variants: Thixo A for addition (platinum) silicone and Thixo C for condensation (tin) silicone, intended for brush-on moulds and upstanding edges.

Accelerators and retarders: control the curing time

Too little time to de-air, or too long a wait before demoulding? With the condensation accelerator and the Pt Cat 10000 platinum catalyst you shorten the cure; with Vinyl D4 you slow down addition silicone. The platinum catalyst also helps against inhibition when an addition silicone refuses to cure properly because of a contaminated model.

Additives for feel and finish

SAM Deadener 1000 takes the bounce out of addition silicone and gives a gel-like, skin-like feel for SFX and prosthetics. LSR Topcoat HE is a matting, wear-resistant, low-friction coating for LSR, HTV and RTV parts.

Cleaning and pre-treatment

Adhesion and release start with a clean surface. Isopropanol 99.7% degreases models and tools, Kirasol 318 SC is an industrial degreaser and oil emulsifier, Chemlease Mold Cleaner EZ cleans composite moulds with minimal residue and Chemlease 15 Sealer EZ seals porous moulds before you apply a release agent. Cured silicone is removed with the silicone remover.

Frequently asked questions

Glass beads or fumed silica? Glass beads reduce weight and improve sanding; fumed silica controls viscosity and prevents sagging. They are often used together.

Does SAM Deadener also work with condensation silicone? No, it was developed for addition/platinum silicone. When in doubt, test a small sample first.

How much thixo should I add? Start with 1 to 2 percent of the total weight and build up; the dosage is listed on each product page. Too much thixo makes the mix hard to de-air.

Unsure about dosage or compatibility? Our team works with these materials every day and is happy to help.