I’ve read in other posts that some of you do not Gel and use paint on the finished part. We are trying to conserve weight and thought this might be a good way to save a few pounds. Our layup schedual is: 20mil Gel, VE resin, 1 layer 1oz. chopped mat, 1 layer E-BXCFM 1710 infused, 2 layers E-LTi 3600 infused. Our primer would be a catalized polyester and top coated with a base/clear urethane if we skipped the Gel and chose paint. Is there a chance of print thru later. Thanks, Dan
O.K. A guess than?
have done it both ways. depends on the part and application. for the rowing shells I was making before we would do prepreg uni-carbon in the mold without gelcoat. after would scuff the surface and do any minor fills if needed then primer the boat. after we would sand back down to when the carbon was starting to show up again. do a wet on wet with light layer of primer then 2 base and 2 clear. we were able to do a full paint job on a 55 foot boat in and out that added 8lbs. of course you could use a primer in mold then do what I described. I think you will find your part will be lighter than if just gelcoated, but I dont know your part.
from personal experience, using polyester gelcoat on a carbon & epoxy bonnet, adds 1kg. AND you have to clear coat it anyway, unless you have the perfect mold and your product is perfect, where in that case, you just polish it. skipping the gel and just clear coating it saves us 700 gr. making the final product 3.3kg , from 4.0 kg.
I’m not a fan of polyester primer on finished parts, as it shrinks and is not a good primer for urethane paint. Urethane primer is better for urethane paint. Just my 2 c.