I’m looking to see if its possible to purchase a special type of clear for dipping parts in. I know I can dip parts into any clear. But I don’t want to mix a tub of urethane clear coat and have it all harden up on me when I only need to dip a few small parts at a time haha.
Any ideas? I’m thinking that a lacquer clear will work because its an air cured material, but then I have to worry about yellowing and durability :-/.
Thanks!
A the dreaded clear coating…generally, when doing a few pieces it is not a big deal, I know when I first started in the biz, the first few pieces I was clearing, wet sanding, clearing, wet sanding, clearing, wet sanding - then the final coat of clear and they looked killer.
Then more orders came…then more…then I realized how screwed I was…at one time I had a back log of 40 pieces all needing clear and I just dreaded how long that was going to take.
John, are you looking to try to reduce the time required and increase production on the finishing to complete the pieces quicker and get them shipped? We do a heavy volume of automotive parts in epoxy and our back-log is always the finishing. Here is what we do:
We wax the mould as normal, prep the flanges by taping them off, buy some Endura EX-2C, it is a two part polyurethane coating with hi gloss properties, spray up the mould, mist the first coat and let it sit for 10 minutes, then spray a heavier coat. It is not like gelcoat so there is no need to pound it in the mould, if you do it will run and you’ll have a mess.
The suck part is it needs 16 hours to set unless you have an oven or cure source. We post cure it in the mould so I can turn it around in under 2 hours from spraying. DO NOT LET IT SIT MORE THAN 24 HOURS IN THE MOULD otherwise it will not bond well to the laminate and it will peel after demoulding.
Once at 16 hours but under 24 hours do your lay-up as normal, demould it and you can thank me later 
Provided the mould has a high gloss surface, you will get a high gloss part which is sealed in pretty well, we can run parts like this, demould, wet sand with 600 to give the surface a little texture and hit it with one coat of clear, wet sand and polish and you’re done. No pin-holes, no fish eyes (give the piece a good wash down prior to clearing for obvious reasons).
Works really well, this is the best solution we have found to date…we tried normal clears, durtec’s and the like, found this to perform the best. The one thing on shooting normal automotive clear is that it works well on small parts, but on larger ones, we found the resistance of it not so great, the Endura is an industrial coating with high impact and chemical resistance but wet sands like a champ to hi gloss, on some parts we have gotten away with just wet sanding right from the mould and no clear, depends on how good you can shoot it HVLP.
Hope that helps, let me know how it works out for you if you decide to try it.
SLS, why shoot it the second time after demolding?
Endura is a great hi gloss sealer, but still not a clear coat with UV stability. We shoot a normal clear coat as the final, I should of mentioned that…
Thanks [SLS](javascript:void(0);)! I’ll have to do some research on that product. How is the clarity of it? Do you still apply a clear gel coat over that before the fabric goes in?
Right now we spray in a marine clear gel coat w/ [duratecs](javascript:void(0)
high gloss additive. We add in 16 - 20 mills. We let that cure for about 2 hours and then layup the part. We infuse, [demold](javascript:void(0);), trim, sand, clear coat, sand, clear coat, sand, polish. Its not terribly long, but its just a pain in the ass. Not something I’m willing to give up if it sacrifices quality, but something I’d love to optimize.
Ideally, what I’d like there to be is a giant vat with clear coat that does not harden when in the vat. I then can mask the back of the products, dip them into the clear coat, and hang them. Then I’d either bombard the part with heat or UV rays to harden the clear coat. That would be how you catalyze it. That is of course in a perfect world…
Hey John,
Nope, no gel coat, just the Endura, then lay-up…we do all the composites in epoxy so gel coat is out of the equation.
I hear ya on the clear but I don’t think a solution exists for dipping, highly automated coating systems use a lacquer style method which sprays (almost bathes) the composite but that is a conveyor based system.
Let me know if you figure a way out, I think we do similar work, just different platforms (vehicles).
By the way, the clarity on Endura is crystal clear, really nice product to work with but it is high in iso so I recommend a fresh air supply. They have an iso free version, we use that as well but my supplier doesn’t always have it on the ready. It is way more $$ than the normal version.
Good luck and try the Endura, we really like it.
Yeah :(. Lacquer from my experience is not as durable as urethane.
How much is the Endura usually and is it a PE material?
I’ll continue to do research and Ill let you know if I find an easier clear coating method :).
Sherwin williams hpc-15. Ppg2100s both clears dry in 15 minutes.
Perfect shine. If your decent at spraying no buffing. Also knock down the peel ply texture and shoot.
About 200 a gallon but it’s just so damn convenient.