brush on gelcoat?

blastin603

blastin603

Location
new hampshire
anyone ever brushed on gelcoat. if so what brand? i would like to do a thick layer on the bottom of my superjet. all the original is worn off down to bare fiberglass. I would rather re-gelcoat than paint soley for waterproofing/protecting it. It doesnt need to look perfect.
 
Dalton

Dalton

Location
Wisconsin
I've brushed tooling gel coat thinned by 15% with styrene and it didn't go well. I'd try getting an HVLP gun if at all possible.
 
mthomps

mthomps

Location
Cleveland
I thought superjets didnt have gelcoat since it is poly based and the superjet bottom deck is smc, requiring epoxy to mechanically bond? Could someone clear this up?
 
Dalton

Dalton

Location
Wisconsin
mthomps said:
I thought superjets didnt have gelcoat since it is poly based and the superjet bottom deck is smc, requiring epoxy to mechanically bond? Could someone clear this up?
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This is my understanding too. Since he didn't specify what ski he had I assumed it was something compatible.
 
Vumad

Vumad

Super Hero, with a cape!
Location
St. Pete, FL
It wouldn't matter what the hull is made of when building it with gelcoat. Epoxy will bond to gelcoat in a mold when the gelcoat has been applied first. The problem is secondary bonding of gelcoat to epoxy. The gelcoat does not bond well to the epoxy after the fact.

I painted a ride plate with gelcoat and a 1" chip brush. I did not thin it. It was a mother to sand it down. It doesn't go on like paint. It does however fill huge gouges which is why I used it.

I believe you can apply gelcoat with a roller. Putting it on thin using several coats may be your best option. I have never rolled on gelcoat. I've actually only just started using it.
 
mthomps

mthomps

Location
Cleveland
Vumad said:
It wouldn't matter what the hull is made of when building it with gelcoat. Epoxy will bond to gelcoat in a mold when the gelcoat has been applied first. The problem is secondary bonding of gelcoat to epoxy. The gelcoat does not bond well to the epoxy after the fact.

I painted a ride plate with gelcoat and a 1" chip brush. I did not thin it. It was a mother to sand it down. It doesn't go on like paint. It does however fill huge gouges which is why I used it.

I believe you can apply gelcoat with a roller. Putting it on thin using several coats may be your best option. I have never rolled on gelcoat. I've actually only just started using it.
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So the gelcoat will bond chemically to the epoxy if layed up together...thanks.
 
Nate_D

Nate_D

Location
Houston, TX
If I'm not mistaken bottom deck of a sj is painted. Anything you do at this point is going to be a mechanical bond to SMC. Which in my limited experience doesn't bond well to much, but epoxy would be your best bet. I would sand down any remaining paint and fill in the deep gouges with an epoxy based body filler. Hit it was a high quality 2k primer, paint, and clear. Anything off the shelf of home depot and out of a rattle can isn't going to hold up long. If I didn't have the tools, I would do the sanding and prep work and then have a professional paint it.

That's just my advice from my limited experience with SMC, fiberglass, and resins.


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blastin603

blastin603

Location
new hampshire
ya already did that. 2k epoxy primer, black base coat. 4 coats of 2k urethane clear. doesnt hold up for poop. any rock it brushes against gouges down to the fiberglass. pretty sure bottom is gelcoated prior to moulding from factory. maybe i can do
a thin layer of west systems epoxy before i gelcoat as a tac coat to have a good bonding surface
 
Yami-Rider

Yami-Rider

TigerCraft FV-PRO
Location
Texoma
I painted the bottom of my hull with epoxy and gel-coat. Gel-coat is poly based, so it shouldn't stick that great, but i haven't had any troubles with it. I rolled both the epoxy and the gel-coat on, the gel-coat had a little bit on orange pill to it, but a little sanding gets rid of that.

See the first post of my build thread for pictures http://www.x-h2o.com/index.php?threads/pre-season-restore.147607/. The before photo is what it looked like after a couple years of beaching my ski. I usually ride twice a week.
 
Dalton

Dalton

Location
Wisconsin
Vumad said:
It wouldn't matter what the hull is made of when building it with gelcoat. Epoxy will bond to gelcoat in a mold when the gelcoat has been applied first. The problem is secondary bonding of gelcoat to epoxy. The gelcoat does not bond well to the epoxy after the fact.

I painted a ride plate with gelcoat and a 1" chip brush. I did not thin it. It was a mother to sand it down. It doesn't go on like paint. It does however fill huge gouges which is why I used it.

I believe you can apply gelcoat with a roller. Putting it on thin using several coats may be your best option. I have never rolled on gelcoat. I've actually only just started using it.
Click to expand...

This is because polyester gel coat cannot cure when exposed to air correct? So then the epoxy is allowed to make a chemical bond to the semi-cured surface? Or are you mixing surfacing wax in with your gel coat before applying it to the mold and then allowing it to full cure?
 
Yami-Rider

Yami-Rider

TigerCraft FV-PRO
Location
Texoma
I only have experience applying gel-coat to boats and my ski. You have to mix hardener and wax or use wax paper for gel-coat to fully cure.
 
Dalton

Dalton

Location
Wisconsin
^^^That's a good point for anyone thinking of applying polyester gel coat as a surface coat on a part. For epoxy gel coats this wouldn't be necessary.

Edit: Or you can spray/brush your gel coat and then follow up with spraying PVA which has also worked well for me.
 
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Yami-Rider

Yami-Rider

TigerCraft FV-PRO
Location
Texoma
I didn't realize there was a such thing as epoxy gel-coat, good to know.
 
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