Spraying clear gel coat.

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#1

Hello all! My name is John and I’m new here. So here is my question that I’ve been asking for a long time…

I do a lot of carbon fiber work and a big part of my job is making parts. I try to keep the quality as high as possible so I would really like to keep spraying a clear gel coat. Its a pain and sometimes a long process but its worth it to keep my customers happy. I’ve been using silmar249 clear surfboard resin reduced at 15% - 20% and have had good crystal clear results but I’d like to do better.

Can somebody point me towards a good sprayable clear resin? UV or not UV resistant, I use a super high quality clear coat on top of everything so that takes care of it.

I would prefer UV resistant, but again its not that big of a deal if its not. But it has to be a sprayable viscosity or something that can be reduced with out greatly reducing the properties of the clear. I hate reducing the silmar249 because its not a very strong clear resin all together. It just has a very high heat distortion temp so its why I chose to use it for now.

If you guys think what I’m doing is just fine then here is my second question. How can I slow down the gel time? I hate leaving it in the cup worrying that it will gel up in my $500 spray gun.

THanks! I look forward to contributing to this forum :).

John

#2

BTW I already tried using automotive clear coat as a gel coat and I’ve tried the following with lousy results.

Dupont basic clear w/ and w/ out fish eye eliminator.
DuPont snap dry clear w/ and w/ out fish eye eliminator.
Transtar True Finish clear coat w/ and w/ out fish eye eliminator.
and Sherwin Williams HPC15 w/ and with out fish eye eliminator.

I hope some of you take note of this who have the same issue or might one day in the future.

I also used to brush the clear on and it took a very long time trying to keep it from sagging, running, and leaving brush streaks. SO I wont go back to brushing.

Thanks!

John

#3

why not use a pressure pot with a 2.5 tip on your gun? You could easily spray any gelcoat. You can always mix duratec higloss additive in to a gelcoat which will make it much thinner. Or you can use Duratecs clear topcoat in mold, theres a PE and VE available. Or if you do it enough invest in a gelcoat spraying machine, it saves a lot of time.

#4

Check out Simtec coatings in PE, both clear filler/primers and clears with UV inhibitor:

http://www.simteccoatings.com/Productlist.ivnu

#5

Urethane or other car paint clears won’t work in a mold lay up.

Too disimilar materials. Have you tried spraying Duratec clear into the mold first? Duratec makes a clear… NOT the Duratec clear addative.

I sometimes spray just clear gel coat. It has a uv inhibitor built into the one i use. Composites One sells it. It’s a marine gel coat.

Which type of resin are you laying up with?

I add duratec clear addative to my gel coat sometimes because as the guys said it thins the gel coat more than enough to spray with an HVLP 1.4 tip gun. I spray everything with a 1.4 tip with excellent results. Just turn your paint adjust knob in until it mists… lay a couple mist coats of gel coat… let that sit for 5 to 10 minutes, then turn the knob out one full turn and spray it complete to obtain a 15mil coating. 15 mils is like hosing on 4 coats of clear paint ( thickness wise ).

Or instead of thinning your clear gel coat with duratec clear addative, thin with acetone by 10%. Catylize gel coat with just 1% mekp. More than that you are asking to have your gun plug solid with hardened gel coat. I bought my gel coat gun at Harbor Freight for $15. Also use a water trap filter when spraying gel coat.

Clean out your gun with automotive grade laquer thinner or acetone. It takes more cleaning than urethane clear coat to get it all out.

The waterborne clear coats aren’t as good as urethane clear top coats :slight_smile:

#6

WOW , with just 1.4 tip? You have excellent results? I really will try too because usually I am using 2.5tip.
Now about the acetone and catylizer :wink: