Asking for a miracle here I know, but I have a vehicle that was painted in 1984, and I want to change the color. No repair required, I was hoping to just scuff it down, prime, and shoot with acrylic paint. It was painted by a body shop, not the back yard job, so I had my fingers crossed that it was done in Imron, one of the first of the two part paints. Tonight I did an experiment on a small part, soaked a paper towel with lacquer thinner and laid it on there. Bad news, in only about 10 minutes I could scrape paint off with my fingernail. So, it obviously is plain old enamel paint, and not the super duper I had hoped for. Question is, anyone know of a sealer product to cover it with, or do I need to strip, or stay with an enamel product? Problem is, I bought a gallon of urethane paint when I painted the wheels last spring....sure would like to use it.
Urethane over uncatilized enamel is a problem. Thirty five years ago I sprayed acrillec enamel over uncatilized aulcide enamel and had total lifting. Don't do it, an aggressive da and 120 grit paper will remove the last paint job quickly.
You've gone thus far, mix up a small amount of the new paint and prep an area like you plan. Shoot it and see. Either way the whole car needs sanded / blocked / sealed. Once you cut thru the topcoat, do you expect the primer to be more stable with urethane ? You could shoot enamel again
I have used epoxy primer as a barrier coat as it has no solvents. No guarantee though.... I'd try it on a small area first as said.
Urethane solvents, while potent in their own ways, are not usually as aggressive as lacquer thinner. Yes, test spots are worth the time, but the paint and catalyst will likely "hit" before there is lifting. Still it's not a very stable base and could wrinkle 2-3 weeks later after a few heat cycles. Sand and seal, let the sealer cure past the non-sanding time. Scuff the whole area with a grey Scotchbrite and don't push hard. Let it scratch it up and you have a decent foundation. Not optimum but I didn't read where you were competing for the Ridler Award so...
Mastercoat Slim solvent proof, goes over any kind of primer and paint, and any kind of paint can go over it. it has a 7-Day window. I have shops that completely Prime their projects top bottom inside and out with it followed by a surfacing primer for blocking
Imron to the best of my knowledge is a blend. Polyester and acrylic blend. Lay a rag with enamel reducer on it within 10 minutes it will attack it A full polyester will do 90 days immersion in acetone without softening It's possible you might have Imron on your car
Sounds like an amazing product. will do an experiment with urethane reducer next https://nomorerust.com/store/home/20-mastercoat-sprayable-slim-permanent-rust-sealer.html
I'd feel more confident (in long term) by sand off, and start again method. Even Imron, by Dupont(?) was an attempt to seal off, followed by 'Start Over!"
About 20 years ago I got a call from Vintage cars in South Carolina. They were using the silver which was that time Slim. Everybody usually starts out painting floor pans and crap like that. They had noticed when they smeared a paint brush against a rusty fender in the back of the shop it never rusted . they asked me why they couldn't prime the entire car with it as to minmize comebacks I told themI don't see any reason why you can't. That was 20 years ago they're still doing it today and they show their cars at Hershey every year . I am proud to say that they are my customers and still are. I don't know how many cars in the last 30 years have my paint on them. I hate rust As for waterborne paints I have no experience whatsoever in waterborne paint. It's worth an experiment.
If you want to shoot acrylic lacquer over it you can seal it with catilized epoxy primer. That is what I am useing for primer on my lacquer jobs. I give it two or 3 days to gas out but I was told by the guy who turned me onto the process that as long as it is dry you arr golden.
I've never been lucky enough to succeed with what you are trying. It is difficult to redo so I usually work on the safe side.
You are absolutely correct Anthony. The problem is I foolishly bought a gallon of acrylic already. The story is, Its a 52 willys m38 army jeep that is really a good one. rust free, all original under the hood. When I bought it they had just started to make it a high school kids jeep, with roll bar, chrome wheels, black vinyl top etc, and I want an army jeep. It came with all the original wheels, and 1952 dated NDT tires. I sandblasted the rims, epoxy primed, urethane paint, new NDT's, all good. It also came with the letter from the guy they bought it from in 1984 when I am guessing the deal was done from the sunday paper, and snail mail correspondence before Al Gore invented the interweb. The letter brags about the new paint job professionally done, and the new chrome wheels, and new top. I was hoping the pro shop put on pro paint, and if not I figured I could seal it. Funny, Midwest Military near me where I buy parts and OD paint, tried to talk me out of it and buy the enamel version, but my mother didn't give any common sense it seems. Today I bought a quart of DP epoxy primer and catalyst to continue my experiment, but at the same time I am starting to see it will cost less if I dump the new gallon of urethane on the ground and buy some enamel instead of trying to seal bad paint with expensive products. I will use the DP on other projects, nice to have it in stock in the shop, but like every thing else prices are going up on cheeseburgers and paint. The Mastercoat slim mentioned above by Pat is only 42 bucks a quart, that may be the best way out of my corner. Thanks guys for all the response.
I think I have put up these pics before. Its a jeep thing, most wont understand, but @anthony myrick will get it. Here's the day I bought it, and later after I striped of the kid stuff. Spotless clean, the PO hardly ever drove it in 40 years. Top still looked brand new. Still OD green on the under neath floor. Sure wish I got it before they painted it.
Since ya mentioned DP. PPG has an industrial epoxy that’s much cheaper than DP. I’m curious about the master coat as well.
Here's what I would do. I would DA it down with 220 Grit. wipe it down down with wax and grease remover. Apply 2 THIN coats of the sealer over it about 2 hours apart. You can put a surfacing primer over it, or you could just paint it with your military green. The sealer uses aromatic solvents that is not very aggressive by applying the first coat on very thin less chance of lifting the previous paint. Once you get the first coat down it's sealed and you're good to go.
Well, finally an update, I guess I move a little slower these days. First a booster for @Pats55 and his product mentioned above, MasterCoat Slim. The product did what he said it would, sealed up my old paint to shoot modern urethane over the top with no lifting issues, and its sand able . Pat was a pleasure to do business with, and even sent me a sample of his rust remover product which is good as well. I had previously bragged that the old paint job was "professionally " done! Well, silly me, lots of issues once I got started on it. The "professionals" had sandblasted the whole jeep without taking anything apart. So, places that didnt get hit, or were hard to access had about 3 layers of paint that I needed to atleast make an effort to feather out. Not trying to make a show car, its a jeep, but still you cant just paint over the last guys mistakes. They did at least do a pretty good prep job, nothing was peeling off , just more prep for me because I did remove some things to do a decent job of it. I removed the hood-fenders-windshield frame-and all the brackets on the outside of the body so there was at least some places to use a sander instead of my fingers. Fact is, there is very little on a jeep that can be sanded with either a DA or an electric orbital, there is just not much that is flat. Then, even the few flat spots, like the sides of the fender wells were warped from the sand blaster so the machine can not sand lumpy surfaces, your fingers do that. I had originally thought this was gonna be a scuff it with scotch pads and paint !!! Been playing with cars for 50 years...should know better ! I also rebuilt the transmission/transfer case, steering box, new windshield , wired it for two tail lights and brake lights, gutted out the "blackout drive" portion of the tail lights and had a stained glass lady make glass lenses so I could wire them up for turn signals. It should have some new canvas seat covers, and a new army top, but Im done for now. Took it to town today for the first drive and a tank of expensive gas, and by golly she just ran down the road so smooth and quiet (transmission was badly damaged by water, and the PO discovered it did not leak if it did not have any oil in it ) , new clean and expensive windshield, Its all good. Time to drive it !
Forgot to mention, I welded 57 holes shut !!!! I had figured a few for the rollbar, but then all the snaps for the top, and the army must have had something mounted on the floor in the back, 57 !!!
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