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Gelcoat?


Guest Darth Revan

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Guest Darth Revan

I need some help with info on gelcoating.

 

What is it?

 

Pros and Cons?

 

Inside and/or outside of a casting?

 

Let me know what your thoughts and experience with gelcoating.

 

Thanks

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Guest Cleverlilminx

I believe gelcoating is a paint and it is applied to the outside.

 

It has nothing to do with making the mold.

 

IRG fanmade helmets are normally fiberglass with a red gelcoat finish.

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Gelcoat is a high quality surface coat over the top of fiberglass, usually made of resin. There are two types... a super-durable kind that is used to face the inside of molds which are going to be used many times, and a more aesthetic kind that is used for the outer surface of fiberglass castings.

 

Gelcoat is thicker than normal fiberglass resin, so it sticks well to the sides of a mold or casting. It comes clear or in various colors, and must be mixed with a catalyst, just like normal resin. When casting into a mold, you first put in a generous coat of gelcoat, let it tack up, and then you apply your fiberglass behind it. When you are creating something without a negative mold, you first do the fiberglass, and then you paint on a topcoat of gelcoat.

 

The best source for gelcoat is marine shops, because it is used heavily as the outer glossy surface of fiberglass boats.

 

You can also make your own gelcoat by mixing normal fiberglass resin with talcum powder to thicken it.

 

Gelcoat provides a very glossy surface which can be sanded smooth without fear of bringing fiberglass fibers to the surface.

 

Pam :-)

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Yes, it will lose it's gloss... but that's a good thing. Most of the time you won't be able to find a gel coat in exactly the color you want, or you'll want to give it a nice clear coat, so you'll want to prepare the surface for painting. Sanding will give a good surface for the paint to bond with.

 

Most of the time gelcoats are intended simply for giving a perfect "face coat" to the work.... for the kind of things we make, it's usually not intended as the final outside color. I do use black gelcoat for my Mara shin guards, but not for the color itself... I use black because that way if the black paint is scraped off, there will still be black underneath and the scratch won't show up as much as it would if I had a tan color underneath.

 

The best results come from wet sanding the gelcoat with a very fine grit wet/dry paper before you paint.

 

Pam :-)

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Guest Anonymous

Hi there,

I make my own gelcoat as you said, by mixing talcum powder into my resin.

You want it quite thick and spreadable so it wont run down the sides of your mold.

Note, it will thin a little bit when you add the hardner.

Also, you don't need it to set up to start adding the fiberglass...just start immediately.

 

:)

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Guest Anonymous

When making your own gelcoat can you add a coloring to it and if so what kind of coloring agent can you use?

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When making your own gelcoat can you add a coloring to it and if so what kind of coloring agent can you use?

 

 

Oops.. sorry I didn't spot this post sooner!

 

I imagine there is probably a source for gel coat colorants... but I don't know what or where they would be. Typically, if you want a colored gel coat, you purchase it already colored. The best place to find colored gel coats is at marine supply shops.

 

Your best bet if you want to look for something like that would be to try the marine shops, or try a web search. If you find something, let us know!

 

Pam :-)

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