Gel coat

[WFO Speedracer]

I have been thinking about this gelcoat will not harden over epoxy myth,there is one aspect to gelcoat that I did not touch on.Gelcoat will not surface harden in the presence of air,now in a mold on a new boat that is not a problem however when doing a surface repair its a problem,there are several ways of handling this issue,one is shoot the gelcoat and not worry about it,there will be a thin layer that will not harden,use acetone and rags to wipe this off the remaining gelcoat under it will be hardened.The second way is to use a wax additive in the gelcoat when spraying,a certain # of cc's of wax additive are added to the gelcoat and it is then sprayed,the wax floats to the top and seals the surface.The third way is to use patch aid in the gelcoat,same thing add it to the gelcoat then shoot it normally.The fourth way is to shoot the gel the overshoot it with PVA,the result is the same.The last way I know of is to add Duratec clear at a ratio of 50/50 to the last coat of gelcoat,the Duratec will seal the surface and let it harden,plus it will bring the gloss up and save lots and lots of sanding.

 

[jondotcom]

You must be talking about epoxy primer here because I have shot gelcoat over epoxy repairs way more times than I can possibly recall,when I worked at the Ski Nautique dealership epoxy is all we used for repairs,it is also all I have used since,I have never had a problem with using gelcoat over epoxy,it is a myth.

I say epoxy for both repairs and top-coating the lower hull. You can tint epoxy black, and it also self-levels. The reason I like it more than paint is due to the thickness and durability. Paint is more prone to fail in the same thickness. Just make sure you use super hard epoxy. If you beached on a concrete ramp with the oem finish you'll take the stock paint right off, but it will only scuff a nice epoxy coat.

 

[McDog]

It was 3:1 epoxy with cabosil from us composites. The gelcoat hardened everywhere except over the repair. I used west system gelcoat. It is not a myth. I put some fancy primer over the repair and it hardened fine. I used PVA on the interior of my hull after I painted it on to make sure it hardened there.

 

[Watty]

The idea of flowcoat is that it's like a regular gelcoat, but it will harden when exposed to air...It contains all the right gear to make it happen.

As WFO said, gelcoat is mostly for mold layups, nd will never truly harden, unless it's sealed in.

Epoxy high fill primer on the bottom, smooth and spray again until you're happy, then hit it with flowcoat. It's easy to repair and respray too.

 

[WFO Speedracer]

It was 3:1 epoxy with cabosil from us composites. The gelcoat hardened everywhere except over the repair. I used west system gelcoat. It is not a myth. I put some fancy primer over the repair and it hardened fine. I used PVA on the interior of my hull after I painted it on to make sure it hardened there.

As I said before we used West System epoxy exclusively when I worked at the Ski Nautique dealership,I personally did hundreds of repair jobs with it,all I can think of (with the exception of the painted jet skis of course) were gelcoated right on top of the west system 410 fairing compound,I never saw a single one with gelcoat that did not harden over the repair and belive me some of these repair areas were massive,I have repaired boats that trees fell on,one that was being suspended in the air and the metal supports came loose from the transom and ripped straight through the rear deck,skis with the noses knocked clean off,you name it I did it.The only gelcoat problem I did see was one someone else did and they tried to gelcoat over bondo,that gelcoat did not harden.I say myth busted.

 

[deblaster]

A few years ago I bought some gelcoat from west marine that had the wax already added, I don't think they sell it anymore. It held good for a few years.

 

[McDog]

As I said before we used West System epoxy exclusively when I worked at the Ski Nautique dealership,I personally did hundreds of repair jobs with it,all I can think of (with the exception of the painted jet skis of course) were gelcoated right on top of the west system 410 fairing compound,I never saw a single one with gelcoat that did not harden over the repair and belive me some of these repair areas were massive,I have repaired boats that trees fell on,one that was being suspended in the air and the metal supports came loose from the transom and ripped straight through the rear deck,skis with the noses knocked clean off,you name it I did it.The only gelcoat problem I did see was one someone else did and they tried to gelcoat over bondo,that gelcoat did not harden.I say myth busted.

Dude, myth not busted. I used us composites epoxy, not west system. It was west marine gelcoat. I assure you it didn't harden over the epoxy repair. I sure wish it had.

 

[WFO Speedracer]

Dude, myth not busted. I used us composites epoxy, not west system. It was west marine gelcoat. I assure you it didn't harden over the epoxy repair. I sure wish it had.

Well I don't know what problem you had in your particular case,but I do know as a general rule using gelcoat over epoxy is not a problem,not going to continue arguing with you I have enough repair jobs out there that speak for themselves.:sad6:

 

[crashnburn86]

i didnt mean to make such a fuss:bananapowerslide:lol

 

[restosud]

repaired a few ski hulls with system3 epoxies.
wherever i used polyester based product on top of repair i had problem with adhesion and peeling or bubbling up.
something is going on at the junction of these products.
contacted system3 and was told that sometimes it works,other times not.idk? but they did say to shy away from mixing.

 

[WFO Speedracer]

i didnt mean to make such a fuss:bananapowerslide:lol

No fuss really and it also helps make my case for West System being different from other epoxies as well,its all good.

 

[Pablo]

as an added anecdote, i had difficulty with my 3:1 epoxy mix hardening in some areas near the bottom of my hull where I had reinforced the sides of my ski and had already painted the bottom (inside floor) of hull with high temp paint. It took 3 nearly 4 days to completely cure in a temperature controlled environment. My shop temp runs 68-72 degrees. The rest of the epoxy/fiberglass areas cured within 4-6 hours. This was a US composites epoxy mix and worked flawlessly elsewhere on the same batch.

 

[Motorheads5]

It's a jet ski not a yacht ! Gel coat is a waste of time on a standup jetski. When you are done riding them most people usually load them up in the truck or on the trailer and haul them home.Use epoxy primer and acrylic enamel with a catalyst and forget it.This is just my opinion.