Gelcoat over epoxy?

[FishStretcher]

I read that it shouldn't be done, then I read from West system that it can be done. Anyone ever done it? I am rather heavily modifying my console and the patches will be epoxy. I don't want to spray a urethane like Awlgrip. Doesn't mean I won't, but I prefer to try gelcoat here. Especially as I will probably use it later on a molded part.

Basically I cut off the seat on the center console door and epoxy/glassed over it. A hack job, but I didn't have the luxury of time to do it nicely. And the epoxy allowed me to use XPS polystyrene to fill the hole and prop up the epoxy/glass during cure without dissolving, like if I used polyester.

[bly]

Originally Posted by FishStretcher

I read that it shouldn't be done, then I read from West system that it can be done. Anyoen ever done it? I am rather heavily modifying my console and the patches will be epoxy. I don't want to spray a urethane like Awlgrip. Doesn't mean I won't, but I prefer to try gelcoat here. Especially as I will probably use it later on a molded part.

It is a high blush epoxy. Anyway. No matter which epoxy you use. You can still gelcoat. If it is a blushing epoxy like west then make it blush, That means forcing the amine solution out rather then it coming to the top later and lifting the gel coat. I used to gel coat west system all the time. Then lightly sand and gelcoat. Now I use much cheaper USComposites epoxy and have never seen it blush in 10 years.

[FishStretcher]

Thanks!

Well, the hardener is ancient (but free, along with the resin- which is nice) so I mixed it 10% hot on hardener, so there is even more amine than usual. But the next layer I will mix correctly.

Good to know. It is just a door, so it is a great place to experiment. I plan or brushing on the gel coat. Along with the touch up on the console proper.

Next on the list is a vacuum bagged fuel tank hatch (mine is a resin rich pig of a thing) and splashwell for a master angler 20, as I can't find one. Probably epoxy/carbon with gel coat. Or vinylester/carbon.

[bly]

Originally Posted by FishStretcher

Thanks!

Well, the hardener is ancient (but free, along with the resin- which is nice) so I mixed it 10% hot on hardener, so there is even more amine than usual. But the next layer I will mix correctly.

Good to know. It is just a door, so it is a great place to experiment. I plan or brushing on the gel coat. Along with the touch up on the console proper.

Next on the list is a vacuum bagged fuel tank hatch (mine is a resin rich pig of a thing) and splashwell for a master angler 20, as I can't find one. Probably epoxy/carbon with gel coat. Or vinylester/carbon.

If it has not blushed on its own? It usually happens very quickly in spring weather conditions. To mimmic that I think I warm it a bit with a heat gun or quartz light. then spray it with some water and let it cool and sit over night. Then warm one more time the next day if it has not blushed. sometimes it takes a second try to get it out. Just wipe with clean rags and let dry and then sand a little bit.

[pelican]

Originally Posted by bly

If it has not blushed on its own? It usually happens very quickly in spring weather conditions. To mimmic that I think I warm it a bit with a heat gun or quartz light. then spray it with some water and let it cool and sit over night. Then warm one more time the next day if it has not blushed. sometimes it takes a second try to get it out. Just wipe with clean rags and let dry and then sand a little bit.

excellent advice jay

a guy i know,"mad mike" - he plays WAY above his skill level - he grabbed some products from me to make "gutters" on his shamrock - a few days later,he returned and complained "that stuff you gave me never set up" !? - i asked him what happened and how he applied it - he explained...the i aksed him if he removed the blush from the epoxy ? i got the blank stare...
he used west system,and he was also using a chopped strand putty over the west...not really sure how he made out with the mess he created - somethings are better unseen...

[shine]

I can help on thi one

gelcoat/polyester WILL cure over some epoxies. You have to make certain its compatible. The epoxy has to be completely cured too.

Do not mix epoxy outside of its designed ratio (hot), all your doing there is introducing more hardener molecules than needed and the epoxy will not cure fully or even at all. The hardener in epoxy is not just a "catalyst" like in polyester, its actually part of the combined epoxy molecule. Catalyst for poly basically "tells" the polyester molecules its time to become hard. Epoxy resin and hardener are more like couples at a dance, mix in too many males or females and you end up with leftover resin or hardener with no where to go = soft epoxy.

[strick]

Originally Posted by shine

Epoxy resin and hardener are more like couples at a dance, mix in too many males or females and you end up with leftover resin or hardener with no where to go = soft epoxy.

Back in the day we had no problem with the left over females

strick

[FishStretcher]

I am getting closer to gelcoat time. It is slow going borrowing a basement in winter to do mods.

I know enough to spray PVA on after the gelcoat so it cures. But How thick can I put the gelcoat on. What i sanded off was probably .04-.06" thick? Not much more than 1/16". I am wondering how much I can hide? And are there gelgoat thicknesses/viscosities I should be looking for, like runnier versus thicker? I am wondering how much 1708 biax print-through I can cover up.

This outer layer has the right resin ratio with the slower hardener- a 40 minute plus pot time is much nicer to work with. I plan on sanding with 40 or 60 grit and sandblasting where I can get away with it. I assume it can cover this?

I am going to re-use the bottom of the original seat as a hatch and make the door semi-permanent and a 150 quart cooler as a seat instead. I got tired of opening the giant door in the smallish 20 foot master angler for every little thing.

[FishStretcher]

Is there someplace other than We$$$t Marine wher I can get gel coat retail for under $50/ qt?

That's the Woburn, MA price. I might want to apply it this weekend, so mail order isn't gonna do it.

[fdheld34]

Look up compatible gelcoat on line and take ad pricing into West Marine..they will match it!
Just make sure it is the same that West Marine is selling...I do this frequently......
Looks like you might be limited to Evercoat on the gelcoat though

-Fred