Gelcoat with aerosil

[mrdebian]

Hi all,

I would like to ask please if there is any ‘danger’ using gelcoat with aerosil.
For example I want to make gelcoat a little bit thicker to go in difficult parts of a kayak mold and to get more thickness. Same when using it to create the seam of a kayak.

Thanks

 

[gonzo]

I use it for building up thickness on repairs with no problems. However, it is difficult to sand. Leave it a bit low and then fill the last thin layer with gelcoat only.

 

[fallguy]

I have combined fumed silica with paint for a hard surface and it is a nightmare to sand.

I think the risks outweigh benefits for you. The surface will become irregular and probably a greater demould risk. I'd be more inclined to want consistent mechanical key for follow on layers versus no key in low spots. But no experience here. I understand Gonzo's point, but he is not pulling on the surfaces of repairs unless he means moulds.

 

[gonzo]

I mean to fill repairs like in gouges and small holes. I leave the repair low and then finish with straight gelcoat.

 

[Youssef Hamdy]

If you want to create a gelcoat putty that you can sand easily as well, I would recommend mixing the gelcoat with Fumed Silica and Microballoons together. ratio is around :
for 1kg gelcoat, use 20-30gm max fumed silica and 70gm microballoons. you can test and tweak it a bit to reach the viscosity you want.. the microballons are also called microspheres or glass bubbles. check out the 3M Glass Bubbles 1k for example for that. the purpose of the glass bubbles is to make the putty easier to sand. only downside is that it causes it to be slightly weaker against indentations from impact, but in your application it should be fine...

 

[redreuben]

In this part of the world gelcoat can be ordered as brushing or spraying.