Respraying a GRP Body Shell

I am thinking of respraying my car but as it already has the current yellow, the previous colour (red) plus god knows how much primer and base coat on I was wondering if I should strip the paint off back to the gel coat or paint over what I have.
If I strip it back what's the best way, rub it down until it's back to the glass or use paint stripper, if stripper what's the best sort to use?

Heat gun,but be very carefull not to get too much heat into the Glass Fibre,just enough to soften the paint,use a scraper with a good square leading edge on it,it does not want to be a knife edge.

I think it looks nice in yellow. There's also a good chance that it won't go faster in another colour.... unless you're stripping more than about 20kg of paint that is! But if you're really intent on doing it, I'd got for a gallon of Nitromores (sp?) ;)

Tim be very careful if you are really thinking about paint stripper as it doesn't only attack paint but most of the other stuff as well. I would flat it off with the D A sander otherwise you will probably wish you hadn't touched it.

Tim be very careful if you are really thinking about paint stripper as it doesn't only attack paint but most of the other stuff as well. I would flat it off with the D A sander otherwise you will probably wish you hadn't touched it.

Agreed!

Tim be very careful if you are really thinking about paint stripper as it doesn't only attack paint but most of the other stuff as well. I would flat it off with the D A sander otherwise you will probably wish you hadn't touched it.

Can you sandblast surfaces like that? Or is it too aggressive on the panel?

some of the scimitar and TVR boys have experimented with paint strippers for marine applications (ie fibregalss hulls) and also bead and ice blasting to remove many years of paint. to be honest the results ive heard and read about, still need a fair amount of scraping and then sanding in the case of paint strippers, and very careful blasting due to varying thicknesses of gel coat and the panels themselves. Ice blasting is supposedly less agressive but the shell will need to be thoruoghly dried, baked or whatever to remove moisture from the grp panels or it will blister the paint work soon after the paint jobs completed. which ever way you do it, theres a fair amount of labour and/or cost involved.

That would almost suggest it is easier to buy new GRP panels?

Not a good idea to shuv any G F into an oven,there is a very strong risk of the whole lot warping.Plus of course,it can weaken the resin which is a major problem.Heat gun is different because you only need enough heat to soften the paint,then it will scrape quite easily.

to remove the moisture i was suggesting a paint shops low bake oven, enough heat to dry the panels but not enough to damage them. gives an consistent all-over temperature rather than the localised heating of a heat gun.
personally if its just for a colour change, i wouldnt bother removing the original paint, as mentioned by someone else here, unless theres 20kg of paint already on there, its more ball-ache than its worth.

The reason I was going to remove the original paint is because every stone chip shows through so at the moment I have a yellow car with red spots.
After reading the posts on here though I think I'll just live with it.
Thanks for the replies.

Perhaps then consider the other approach and apply stone chip prevention film to the at-risk areas?

Jim

Perhaps then consider the other approach and apply stone chip prevention film to the at-risk areas?

Jim

3M make some really good quality films in this area... as used on exotic road cars.. and with the right installer... will stop the stone chips. Adds weight to the car... but the reduction in pock marks should be the benefit

we did it on our race car, FRenault, bloody hard work, but wow looked good afterwards!!
lots of sand paper, and wet and dry.
stopped it being any heavier that it was b4 (was a bit heavy as it was)
as they say, its all in the prep!!
Paint is heavy remember, Ferrari used to use special paint, cos red paint has iron in it to make it red, (rust colour) and they used to not use much paint. dunno if thats still true with modern paint!

As a painter by trade, i personally would sand all panels as smooth as possible and then use a high build primer. These are useually beige or grey but you can tint them with some of your top colour, this not only helps the top coat cover easier, it dosn't stand out as much if it's chipped.

One major concern about baking (low bake oven) GRP panels, is no matter how old the panels are there will still be solvent residue in them. This has a habbit of popping once heated.

Modern two pack paint is just as hard after airdrying anyway.

Richard

having just bought a grp car, which has had the hard bit done (GRP repairs and stripped back to gel coat ) would it be right to say that leaving the bodyshell ( its monocoque) somewhere warm and dry at aound 25-30 degrees for a day or so to thoroughly dry out and then prime, finish, dry again and 2 pack left to air dry is going to be my best bet ?

25deg would be enough Zef,in fact it would be perfect. Nice 2k high build primer --suck eggs etc.

About time you bought a nice Grantura,Espers starting to get lonely!

Zef:

Having had quite a bit to do with older GRP bodies, I would proceed with huge caution!

The worst were Lotus Elites (the original Climax engined car), early Elans; and probably worst of all, Jensons Interceptors.

Only solution was to flat off the gel coat and re-gel!

And then build up the surface again. Hours and hours and hours!

Same with early single seater bodywork. Even more vibration crazing as it was so thin.

One of the problems was always that vibration made the gel coat craze: and no amount of filler, surfacer would cure this.

If the surface is stable: let it be!

Paint stripper is a total no-no as it will pull off the gel coat and start activating the GRP layers underneath.

KISS!

ALl thats makes sense, I remember my Dad spending months restoring his Scimitar, probably why he had no finger prints

The car I've just acquired is monocoque ( not an ELite however, it'll hopefully be reliable and affordable!) and has had most of its structural points reworked to a good standard, most of the finishing is cosmetic and whatever we add for the roll cage reinforcement

as its back to gel coat already we can see where all the repairs have been made and where any stress cracks are etc, the general finish/condition seems to be very good given its history !

i would never use paint stripper when fibre glass is involved from my past experiences with it . i would be inclined to sand with a da and course disc like 80 then 180 then block whatevers left with 180 then a light coat of barcoat and 3-4 coats of a good highbuild such as nexa or spieshecker . i would be hesitant to bake anything you put on it i would let it air dry or if you really do have to bake it at a low tempreture .

I would not even think of baking it,but 25deg is like a good summers day,not a problem.

exactly Peter

why I mentioned a 'warm day' kind of temperature in a controlled environment, rather than outside in a Force 8 gale in the fishing rain as has been the norm since I bought the beast !

exactly Peter

why I mentioned a 'warm day' kind of temperature in a controlled environment, rather than outside in a Force 8 gale in the fishing rain as has been the norm since I bought the beast !

"PETER"??

Think Zef looked at the avatar not the name. :laugh:

Think Zef looked at the avatar not the name. :laugh:


:rofl: At least someone was paying attention Falcie:rofl:

your one and the same aren't you ? :rofl:

No,Peter's the one with the nice hair do!:p
Just one thing Zef,if there are any areas that still show signs of crazing,make sure there are no loose segments,they will need to be picked off and sorted otherwise they will always be visable