West System COLLOIDAL SILICA - 5.5 OZ

Great filler from west system A++++++

This stuff works great!! It’s not easy to mix into the epoxy, it’s so insanely light, it just floats away if you’re not very very careful!! Add a little at a time, mix inside a garage or somewhere the wind can’t get to the mixing bowl. Once it’s mixed in, it does a great job thickening up the epoxy. Great for vertical surfaces as it really holds upright well once mixed to the proper thickness.

Works well for fairing, very strong

I used this to thicken the epoxy so it wouldn't run down through large cracks and nail holes in a rustic oak floor. Unthickened, the epoxy would disappear as quickly as I could inject it. This is a great system. It's very easy to mix this in until you get the desired thickness. I spread it on with a stick, smashing it down into the holes.

The West System Silica additive worked great for filling the small gap that I had after installing the wood floor in my boat. It exceeded my expectations.

This does exactly what it’s supposed to do….it thickens epoxies. I’ve used it in West Systems and 3M toughened epoxies and it performed similarly in both. But colloidal silica has two qualities that you MUST plan to accommodate: (1) it is extremely light and “fluffy, and (2) you do NOT want to get it in your eyes or lungs. (It’s essentially a super-fine glass…if it gets into lung tissue it’s likely there to stay.) I’m not sure what kind of container might work better, but the lid on this canister is difficult to open without creating a plume of silica. So put your mask on before you start, sit the canister in a fully upright position on a stable surface, then remove the top very slowly, and only in a still air environment. Similarly while using it, scooping it out of its container and stirring it into the epoxy both create airborne plumes. Because you need to mix it in slowly and gradually, I’d avoid using it in fast epoxies. I used it in 20min and 60min mixes without issues. All those usage warnings aside, it works great. I needed to mix my epoxies to a thick paste consistency. It took awhile (and a surprising amount of silica!), but I added gradually and eventually got it just right.