In my opinion the color of the resin isn’t nearly as important as what the color of the resin will become after some exposure to UV light. Many resins will really yellow/brown out after exposed to the Sun. Naked carbon parts then take on a nice army green tint.
Thats why you need to clear coat the parts with a nice high quality urethane clear :). ^^^
Lol before I got into composites I was an autobody tech at a few shops. Once I spread bondo on an entire quarter panel of an Ford E150 to then find out I forgot to add hardener :o.
In my deffence we used cream hardener so I couldnt tell…
With resins that have UV inhibitors in them a clear coat is unnecessary. Resin Research 2070, Adtech 820, and MGS 285 are some epoxy resins that infuse nicely and won’t yellow in the sun.
I assume that you are shooting the mold with your clear coat so you don’t have to shoot is after molding. 
The UV inhibitors in epoxys just slow down the yellowing process. The best UV protection is a UV clear coat or the polyurethan in mould coatin I use.
DDCompound, what kind of in mold polyurethane coating do you use? This painting after demolding is a lot of prep work.
You can shoot just about any clear-coat into the mold before infusion.
My experience with a Dutch brand of PU clear is that you need resin on the surface of the coat within 20 minutes or so, or the adhesion is gone.
The one I use has no open time, the adhesion is always perfect, just after one year. It is the IMC from HP Textiles, but they can not ship it to the US. I think we will try that our US importeur will also sell it.
Not all clear costs have the same UV protection!
I use PPG Deltron DC300 High Velocity clear coat. I cure it before layup with an IR lamp in 15 minutes or use the oven to force cure it. Almost all the parts that I fabricate come out of the mold painted or clear-coated. I’ve yet to find a paint that didn’t bond to the layup…even if the paint cures for weeks before layup. I’m sure there is some out there but I haven’t found one yet.
A few years ago we had a resin that wouldn’t release from Frekote 770nc, Zyvax, or McLube. Even with a fully cured 2K Urethane in the mold before layup the stuff would still stick.
Do you guys sand the clearbefore infusing?
I have never found the need. I only use epoxies though which have better adhesion than PE an VE. Obviously, you should do some testing first with your clear-coat and your resin.
I am interested in trying this resin as well. Does it have UV protection?
Thanks for the tips on the poly-urethane. I use PPG so I’m anxious to shot some on a mold and infuse.
Ro Yale, what release system are you using? Do you have a curing oven? Which PPG clear coat? The hardest part of spraying into the mold is preventing fisheyes and beading. I can give you some tips if I know the release system.
Wyowindworks, I use Frekote 770-NC. I also have some Frekote 700. I also have some ChemLease but I’m not too sure about the part number. I have a small oven but not large enough for my molds. How about a heat gun? I use PPG 2010 and also Sherwin Williams fast cure clear. Any help will be appreciated.
Your first coat needs to be a really light mist coat. Do this by releasing very little product out of the gun. I set the stop to just barely allow the needle to open. This first coat needs to setup before progressing with a heavier coat. I zap it with an IR lamp after flash or put it into the oven to force cure it according to PPG’s guidelines. You could probably speed this up with the heat gun. Once the mist coat is set you can test is by spraying a little heavier coat. If this looks good then you can put on a thicker coat.
The problem with semis is that the clear coat is very prone to fisheyeing and beading on Frekote. You can over-reduce (150% of normal) to help out. The key is giving enough time for the mist coat to setup so it doesn’t soften by the following coats.
I’d recommend that you practice on a Frekote treated test coupon. This way you can see what spraying on Frekote is like. Your first couple of attempts can feel frustrating. Once you get a process dialed for your paint then it’s pretty painless. Messing up a test coupon is much better than a mold. Also, you should go ahead and test the process by performing a layup on top of your clearcoat. Some resins will cause the clearcoat to end up soft or hazy. Some work beautifully.
I’ve heard that spraying on Chemlease is easier than spraying on Frekote 770-nc.
Shooting single component paints is much easier than 2K paints. I can shoot a lacquer on Frekote in just a few minutes. 2K usually takes a little longer because you need to let the mist coat setup more fully.
I like to let the paint cure well before doing the layup. Again, a force cure of some form really speeds up production.
In reponse to Clear Coat in Infusion…I didnt think you had to apply a clear coat before the infusion process. I thought that when your part is down infusing and when you pop it out of the mold, the side facing the mold has a clear coat look to it?? Is what I was told right or wrong??
This is correct, however most epoxies will yellow under UV/sun light, so you will want a clear coat with some type of UV protection in it to be applied before, or after the part is laminated.
If you have a nice shiney mold, than your parts will pop out shiney with a nice smooth finish. Spraying your finish coating into the mold before layup or infusion simply solves the issue of having to spray it on the part after it has been infused.
There is a great thread here on the forum about this. Click here to go there.
As for me, I usually have a few blemishes in my parts yet, so I save my clear spraying until after the part has come out of the mold because I’ll have some sanding to do. :o
will 700nc/770nc both cause beading if I was to brush on a layer of epoxy gelcoat instead of 2kClear as an IMC? How else can one apply an epoxy gel coat? Thanks