Car clear coat?

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#1

hey people :slight_smile:

we (the greek guys on the forum) have been having problems with some problematic clear gelcoat , that gells within 4-5minutes ,even with 1% mekp! after seeing the difference sprayed gelcoat versus brushed, and spraying it in large quantities is impossible, without gelling in the spray gun, i decided to turn to different approaches in order to make an outer layer to carbon parts, in order not to have porosity.

i thought about spraying car clear coat inside the mold and then laying up the part (with epoxy resin).

can it be done? must the clear coat be of a specific type? (the usual ones are acrylic i think)

#2

Hmm, your gel coat should not B stage in the cup or gun. Mix 5% acetone or mek with the catalyzed gel coat. Use a 2.2mm or larger hvlp gun tip size. Try using just 0.5% catylist for longer work time. The other probably better gel coat cup gun option should work well for larger parts.

#3

Hmm, your gel coat should not B stage in the cup or gun. Mix 10% acetone or mek with the catalyzed gel coat. Use a 2.2mm or larger hvlp gun tip size. Try using just .5% catylist for longer work time. The other probably better gel coat cup gun option… dump gun it’s called.

I am soon going to try Kleer Kote epoxy as a “gel coat”. Of course it takes much longer to cure before infusion or lay up.

#4

I tried spraying paint into a mold but it just would puddle up and not flow out at all. Maybe is the fact that use semi perm mold releases in all my molds!

Have you tried a dump gun yet?

Try cutting back on the MEKP to even 1/2% or less. It may stay tacky longer but with a slightly hotter lamination lay up, it will help to finish cure the gel coating.

#5

Try working faster. :smiley:

Seriously, 4-5 mins is a long time to spray a bonnet, I use a cup gun and it takes probably two minutes. Why do you have to do it in one shot? Try doing it in two halves…

#6

To answer the question about automotive clear coat, no. Do not use paint in the mold.
Something is wrong with your gelcoat if it gels in 5 minutes after mixing catalyst. Find the problem, and try again.

#7

try DU-POND 1120 its UV stable clear coat, I dont know gell time because I need 2min for spraying it
I use 2.0 HP gravity gun

#8

its not my problem, other people that shop from the same place have the same problems. must be a bad batch, what can i say…

#9

That’s what I mean. It sounds like you guys are doing it right, so there has to be something wrong with the material, unless it is supposed to gel in 5 mintutes.
Talk to the manufacturer about these issues, and get specs for viscosity and 100g gel time. This will also guide you and what nozzle to use for spraying it to get the proper thickness and a nice finish to lay up on.

#10

me and the other greek members (TNT and EliasGR) are gonna buy a 4kg of duratec, to try our luck with hopefully superior materials!

#11

Uh oh. I hope you mean their Dura Kote clear gelcoat, and not the clear top coat.

#12

we havent bought anything yet, i`ll talk with the salesperson beforehand.