Primer help for fiberglass
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Hi all,
I have a friend that wants me to paint a 72 Corvette for him, but due to the multiple layers of paint on it he’s wanting to go right back down to the gelcoat.
Now painting ‘glass is something I’ve done very little of, so I’d appreciate a bit of advice on what primer to start with. Is epoxy still the way to go as it would be for metal, or could/should I go straight to a poly primer over the gel, then epoxy over that once it’s level to seal it?
It’s going straight gloss black, so there’ll be a lot of blocking involved I guess!
Thanks 🙂
I’d take it down to jellcoat or glass … do filler work as necessary and then highbuild right over that with no epoxy … I don’t see the need for epoxy 😉
like this cobra http://www.facebook.com/album.php?aid=123581&id=565177326&l=55dec6be55 :pcorn:
That’s just beautiful [img]http://www.talkaudio.co.uk/vbb/images/smilies/hearts.gif[/img]
Thanks for the advice. At least I talked the guy out of using etch! :wak
Fiberglass is probably the easiest thing to paint, because all you need is mechanical abrasion.
No Rust protection, no Adheision promoter. Just plain and simple mechanical bond.I usually hit it with 120 grit (Just for the speed) and throw Evercoat 4:1 on it. (I wouldn’t go that course if you weren’t using a poly like 4:1 though.)
If there’s any damage of course that is where the problem with fiberglass comes.
Once the glasses integrity is failing you have to completely remove out the damage, strip the gelcoat off about 20% exceeding your damage, and then relay new glass, and re-gelcoat/Filler the repaired area.Get er’ done!
I’ve found Featherfill G2 works well on bare ‘Vettes. Nice build for blocking, and seals down the fiberglass grain. Follow up with a good 2K , and your pretty set.
Doing one now with that.
[IMG]http://i419.photobucket.com/albums/pp275/Autobodyman/img39.jpg[/IMG]
We’ve been using alot of evercoat’s new superbuild 4:1 poly on vettes lately. Directly over sanded glass. Nice stuff.
I would recommend epoxy (and so does the paint rep), afterall it won’t hurt. However, like everyone else, I usually have applied polyester or 2k Urethane over the bare fiberglass.
I think the idea with the epoxy is that the fiberglass needs to be sealed since the fibers will “wick up” water/moisture and hold onto it very easily, eventually causing the glass to rot. And way back when, the primers (lacquer) were not adequate enough for this task. So if you use a good 2k product it will do an excellent job adhering to the glass as well as blocking out moisture.
some epoxy primers seem to gum up the paper quickly,id go with a polyester primer for blocking since youll need to do lots of it, and then a good quality urethane to seal it.
[b]Kevin Campbell wrote:[/b]
[quote]I’ve found Featherfill G2 works well on bare ‘Vettes. Nice build for blocking, and seals down the fiberglass grain. Follow up with a good 2K , and your pretty set.Doing one now with that.
[IMG]http://i419.photobucket.com/albums/pp275/Autobodyman/img39.jpg[/IMG][/quote]
nice looking work right there impessive 😉i know quite a few guys that just restore vettes and all seal the glass with epoxy before moving on to any kind of building primer. not that you absolutely have to do it. polyester and 2k primer will stick just fine. its just extra measure. i personally used to paint the occasional yacht hull as well and no matter what the paint company was they always made us put epoxy under.
I have always done Epoxy or polysurfacer. Usually both. I do not go wet on wet between the epoxy and poly though. I always let the epoxy dry very well. My rep told me he has heard of failures from this. I would put a couple coats of epoxy down and let it dry for a week. Sand with 120 and spray my poly. Depending on the surface condition it would get blocked with P80 than P120 and reapply the poly, or P120, P180 and D/A with P220 and 2K.
Both will bond really well. The epoxy first won’t hurt, but I can’t say for sure how much it will help. I think you will be fine with either method.
I do not envy you at all for doing this job! :rofl I always hated painting older vettes. Too much blocking, I like instant gratification!
[b]Kevin Campbell wrote:[/b]
[quote]I’ve found Featherfill G2 works well on bare ‘Vettes. Nice build for blocking, and seals down the fiberglass grain. Follow up with a good 2K , and your pretty set.Doing one now with that.
[IMG]http://i419.photobucket.com/albums/pp275/Autobodyman/img39.jpg[/IMG][/quote]
That is damn nice Kevin! Hell of a job as usual.
I have a 78 Corvette to paint also and the PPG instructor advised me to use their D831
wash primer. I can get the F399 Delfleet epoxy and also D8046 HB 2K primer.
What would you recomend me to use?Dag
I know that Many Etch/Wash primers say that Fiberglass is a compatible substrate.
But can anyone explain to me why an acidic etch primer would be remotely beneficial over a gel coat?
I mean I can’t see it being a bad thing. But at the same time I can’t see it providing any better adhesion.I mean yeah, it also states that an etch primer can be used over OEM Substrates. But none of us are using it over that either. And in all honesty, I can’t remotely see how the acidic primer would remotely increase adhesion on either substrate.
My personal opinion is they tell you this so they can sell more product.
There is absolutely nothing in an Etch/Wash primer that I can see that would remotely increase adhesion to an OEM or gel coat substrate…As far as I can see, Epoxy is good insurance.
Is Epoxy better than a Poly or Urethane? Perhaps, it does retain a better Shear strength meaning it does provide more adhesion. Not required, but good insurance. I would just give it plenty of time to set up.
But in all honesty as long as you seal over your poly, you shouldn’t have any problem.At the same time Gel coats on our Automotive Panels are typically always Polyesters, And Urethanes provide a higher sheer strength then a Polyester Gelcoat. A product can only be as strong as its substrate right?
I think this whole topic is highly debatable.
But in all honesty, I Think all of the above will work.
I would either go straight over it with a poly then seal. Or I would go with a fast cure Epoxy Hybrid before my poly. Either or.
Thanks for all the advice fellas. Certainly plenty to chew over.
I do have a gallon of epoxy lying around that I can’t see me using on anything else, so may well start with that, if only to get rid of it 😀
Double priming was always a favourite of mine Ryan, way back when I was doing ‘real’ work! I haven’t even seen the car yet but I’m planning on one round of poly, then depending upon how that blocks down it’ll be another dose of poly, or straight onto regular 2k high build.
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