Roll/Brush on gelcoat. Anyone have experience?

Quinc

Quinc

Buy a Superjet
Location
California
Been reading on the boat forums about rolling/tipping/brushing gel coat. Anyone have any experience/tips and a brand they like? I want to do it to the bottom of my bob once I finish the patch work.

Or would it be worth the cost of buying the cheapest spray gun at harbor freight and spraying it?
 
Ducky

Ducky

Back in the game!
Location
Charlotte, NC
Curious about this as well! I have read a whole lot, but regardless of where I have read it, there are so many different options or opinion, its like a "what is the best oil" thread.

I am looking to touch up some areas on my Super Chicken, but decided I probably wont even bother.
 
Pablo

Pablo

sqeez bth levrs & lean bk
Site Supporter
Location
georgia
From personal experience, I bought the el cheapo gun @ harbor freight and sprayed my sanded/prepped SJ bottom deck with US composites gel coat cut 50:50 with Duratec clear and dyed it black. Worked like a charm. Nothing wrong with brushing or rolling either. It should self-level to an extent.

I'm still using that same gun from HF from 7-8 years ago. I had someone mixing for me and had them start the mix the minute I started spraying and was able to flush the gun in between coats and get the next coat down as the first was hardening. Total of 3 coats. Held up well.
 
Vumad

Vumad

Super Hero, with a cape!
Location
St. Pete, FL
Pablo said:
From personal experience, I bought the el cheapo gun @ harbor freight and sprayed my sanded/prepped SJ bottom deck with US composites gel coat cut 50:50 with Duratec clear and dyed it black. Worked like a charm. Nothing wrong with brushing or rolling either. It should self-level to an extent.

I'm still using that same gun from HF from 7-8 years ago. I had someone mixing for me and had them start the mix the minute I started spraying and was able to flush the gun in between coats and get the next coat down as the first was hardening. Total of 3 coats. Held up well.
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what size tip did you use? Did you get the clear online? Why did you dye it instead of using black gelcoat?
 
Pablo

Pablo

sqeez bth levrs & lean bk
Site Supporter
Location
georgia
From memory, I used a 2mm tip. The larger tip helps allow u to flow up or down with ur spray versus a small tip and ur locked in on the amount u can spray. I'm pretty sure all I had was white gel coat from a previous ski and bought dye to work this project. I did buy the Duratec online. Maybe US composites or maybe not can't remember it's been so long. Make sure u have acetone available to clean gun regularly. I'm for sure not a body work expert but I went at this blind and it was fairly easy, just mix appropriate and work efficient as the hardener and temps can be ur enemy.
 
Vumad

Vumad

Super Hero, with a cape!
Location
St. Pete, FL
Pablo said:
From memory, I used a 2mm tip. The larger tip helps allow u to flow up or down with ur spray versus a small tip and ur locked in on the amount u can spray. I'm pretty sure all I had was white gel coat from a previous ski and bought dye to work this project. I did buy the Duratec online. Maybe US composites or maybe not can't remember it's been so long. Make sure u have acetone available to clean gun regularly. I'm for sure not a body work expert but I went at this blind and it was fairly easy, just mix appropriate and work efficient as the hardener and temps can be ur enemy.
Click to expand...

A 2 sounds right from what I recall being told by the composites people I buy from. I have a G100 dump gun. It was about $120. It cleans super easy which is nice, but goes on very thick and leaves orange peel so bad that oranges would laugh. If I could do it over, I'd get a HVLP gun like you did. Spray thinner and lighter. I'm sure my parts would be nicer. I do plan to buy a HVLP for the job. I believe @Nate_D got one online specifically for gelcoat about $50 from a composites supplier.
 
Nate_D

Nate_D

Location
Houston, TX
Vumad said:
A 2 sounds right from what I recall being told by the composites people I buy from. I have a G100 dump gun. It was about $120. It cleans super easy which is nice, but goes on very thick and leaves orange peel so bad that oranges would laugh. If I could do it over, I'd get a HVLP gun like you did. Spray thinner and lighter. I'm sure my parts would be nicer. I do plan to buy a HVLP for the job. I believe @Nate_D got one online specifically for gelcoat about $50 from a composites supplier.
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I use a regular cheapo HVLP. Mine are all from TCPGlobal. A little higher quality than harbor freight and they have needle/tips available for them. As for the tips, I use a 2.5 for spraying regular gelcoat for a mold, 2.0 for poly high build primers, and a 1.3/1.4 to spray thinned polyester products. Finer the tip, the better the atomization, the less you will hate yourself while wet sanding.
 
Quinc

Quinc

Buy a Superjet
Location
California
Do you need to brush something onto the bottom of your hull to cover up epoxy (patch work) before applying new gel coat? I sent an email to uscomposits and they told me "Unfortunately, gel coat will not bond to epoxy"
 
Nate_D

Nate_D

Location
Houston, TX
Quinc said:
Do you need to brush something onto the bottom of your hull to cover up epoxy (patch work) before applying new gel coat? I sent an email to uscomposits and they told me "Unfortunately, gel coat will not bond to epoxy"
Click to expand...

Interesting. I would like to hear their explanation of the chemistry behind that statement. Amine inhibition of the cross linking process, but fully cured epoxy that has been properly prepped shouldn't have free amines in significant quantity to matter, I wouldn't think. I could be wrong. I've never personally done any testing. There are "tie in" coat products, but generally used for in mold gelcoats with incompatible epoxy resin systems for the laminate.

UScomposites caters to the more entry level consumer, I think their answer to that question has to do with keeping inexperienced user from mixing generally incompatible resin chemistry. Perhaps someone who has more experience with gelcoat can weigh in.
 
mike b

mike b

Michael "Mayhem" Bevacqua aka MikeyChan
Location
California
I am about to spray the bottom of a ski. Going to use a harbor freight gun and most likely toss it afterwards. Just get something that can put it on the ski cleaner than a brush. Less wet sanding and buffing to that way. I'm sure brushed on can work with good results but I would imagine more material and sanding be needed
 
simofx-1

simofx-1

freeride
Location
new zealand
i brushed my hull white gell coat no primer, has held up well except a few chips that have come off around the tubbies flex points.. im wondering if i should use i primer next time?
 
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