Fumed Silica is a powder suitable for making liquid materials, thick or paste like. When mixed properly without air entrapment this powder will disolve colorless.

This powder can also be used in Siliconen Culinair® because the result is still food safe. This in contrast to the Thixo A for addition silicone which can also be used as a fattening but which is not food safe.
Addition of fumed silica may also increase the stiffness / hardness of the silicone. 

Processing

Fumed Silica is a white powder that is suitable for thickening pourable silicone, polyester, epoxy and polyurethane so that they are less fluid or even paste like. Please note that the powder needs time to wet properly in order to bind the fluid well. The final result will therefore require proper mixing and time. 

NOTE: use small amounts. We recommend that you determine this experimentally. Beginning at 0.5 mass%, and increase in increments of 0.5%

For silicone often a 1 % addition of fumed silica in weight is enough for a spreadable silicone.

For Polyurethane, 

Always start low: Begin with 0.5% to 1% by weight of the total resin (or of component A, the polyol).

• Increase in steps of 0.5% until you reach the right consistency.
• Typical amounts for a spatula-applicable (spreadable) result:
  • 0.7–1%: lightly thickened, anti-sag (non-slump) liquid – still easy to pour but stays in place.
  • 2–3%: gel-like, ideal for most spatula applications.
  • 3–5% (or up to 7%): thicker paste (Vaseline- or peanut-butter consistency) for vertical fillings or fillets.

special instructions

In contrast to Thixo for addition curing silicones or condensation curing silicones the Fumed Silica may be used in both addition and condensation curing silicone 

Fumed Silica also increases the hardness (Shore value) of silicone. With normal thixo this that happens to a lesser degree.

Durability

If dry stored indefinitely.

Product information

Product information sheet Filler Fumed Silica