I'm having my pickup re-painted, and I am doing the prep work. the paint on there now is an enamel(acrylic?) of some sort. some panels are fine and i was just going to rough up the paint with like 600-800 grit, while other panels have some filler work to be done. with these i am sanding down either to the metal or underneath the previous primer and filler. once all the new filler and primer is applied, i was going to put a primer sealer like wanda 2k sealer over to prevent anything seeping up to the topcoat which is a single stage urethane. My question is about the primer sealer. i thought that this was the design of the primer sealer to prevent any chemicals under it from seeping up to the topcoat causing little blisters, but read somewhere not to use it, or dont use it when the previous paint was acrylic enamel or something like that. anyone have a clearer answer than what i read?
First of all, what type of primer in under the acrylic enamel?
If it's lacquer primer, you will have to strip the paint and primer because acrylic enamel has poor adhesion over lacquer.
My first choice would be this route, because I don't like multiple coats.
If you're dead set on painting over the A/E, then you must use a sealer because the basemaker (assuming you will be painting BC/CC) will wrinkle the A/E.
I have painted many cars, and it's always a compromise painting over A/E. I would do all the body work first, then coat the complete vehicle with a high build urethane filler/primer. Let it sit a week before you block it out, and try not to break through the primer.
When it comes time to painting, shoot a coat of urethane sealer then apply your base coat once it flashes, then clear.
You shouldn't have any issues, but like I said, I would rather strip the A/E off the car. You would be surprised how fast you could strip a complete vehicle that was painted with A/E with razor blades.
when I was painting cars years ago I always found that the paint companies kind of made an effort to ensure that their paint was not overley compatible with other brands, if you want it to work out and are not sure of whats there I would remove all paint and start bare
There is an immage that won't go away.Thanks Ray.By the way Robs idea of a show quality paint job involves switching to a vaccuum cleaner insted of his trusty broom. Ed
-- Edited by flatblack55delivery on Wednesday 31st of July 2013 09:09:07 AM
I thought about what I posted yesterday, the previous owner knew nothing about the paint, so neither do I, someone at a cruise once said, oh that looks like acrylic enamel, so I went with that. Its not clear coated though like a 2 stage, its a one stage paint of some sort. How do you tell by looking at the paint what it is? The primer in areas that i have sanded off so far is that Indian red color, doesn't help I know. It has the red basecoat, then the redish primer, then filler, then metal, so dont see any sealer(black/grey) on it now. Of coarse I have no paint code, and already have several reds mixed and it cant be matched either by eye or by damn computer.
Take some lacquer thinner and rub it on the red primer. If it comes off on the rag, you will have to strip the car if you want a half decent job that will last a while.
If you rub the paint with fine sandpaper (500 or higher) and the paper turns the colour of the car, then the car was painted with a single stage paint, be it acrylic enamel, acrylic urethane, or urethane. If the paper turns white, then the car was most likely painted with base/clear. I say most likely, because it is common practice to spray clear over single stage paints.
Don't be concerned too much about what type of paint is on the car, but be more concerned about what primer is under it. If the paint job is 20+ yrs old, I can almost guarantee that they used lacquer primer.
so sanding with 600, showed white on the paper, and rubbing thinner on the primer showed nothing coming off, but on my sunvisor in my avitar, it is black, and that came off, so I can sand that off. then having the painter apply wanda 2k sealer wet on wet with my urethane finish coat sounds acceptable?
so sanding with 600, showed white on the paper, and rubbing thinner on the primer showed nothing coming off, but on my sunvisor in my avitar, it is black, and that came off, so I can sand that off. then having the painter apply wanda 2k sealer wet on wet with my urethane finish coat sounds acceptable?
Good news !! I guess your car was painted with base/clear. You said you rubbed the primer with thinner, but you didn't specify what type. It must be lacquer thinner, because using something like paint reducer won't remove lacquer primer.
I would still shoot the whole car with a high build urethane 2K primer after the body work is done, and let it sit for a week. You can then block the car with 500 dry. This will guarantee that any feathered edge from the original paint wont show through. You can then paint directly over this, but I would still recommend a sealer (not high build) before you apply your base colour( wet on wet).
