Fumed Silica - 1 Gallon Filler Thickening Powder for epoxy, silicones, Paints, varnishes, and Liquids. Fill Cracks, voids and Create Non-Sagging Properties.

I used this to make a gel out of phosphoric acid. It worked well.

Mixes easily and thickens nicely. Shipping is very slow.

I used it with west system to patch a few holes on my boat, and the mixture turned out hard as a rock with no leaks. Differently would recommend and buy again.

Easy to use and works. Could be cheaper though.

It makes a smooth and easy to apply filler for epoxy, polyester, and gelcoat.

This works fantastic for thickening up fiberglass resin and bondo.

Used this gor for thickening epoxy glue for a custom medicine cabinet mirror setup. Light as air and can get messy if not careful. Had a mask on tight as I was leary of inhaling. Get it.

This is a very good product and a lot less expensive that West Systems 406 filler. The only drawback is that you have to really spend the time to blend it well with the resin as it tends to be a little clumpy. A few extra minutes stirring it in will save you money.