My buddy recently bought a 48 Chevy fleetline, the paintjob was horrible and it has a bunch of bondo covering lots of lazy bodywork on the lower fenders. We have been stripping paint and layers on bondo with paint stripping disks and wire wheels and he decides their has to be a better way. So he calls the local sand and media blating place and the guy tells him to stop using the stripping disks and wire wheels because it will heat the metal and cause hot spots and the paint will never lay right in those spots. And then proceeds to him that he won't blast any painted surfaces only bottom and interior of body and frame because it won't look right when we paint it. And to only use chemical strippers. Has anyone ever heard this before? I'm fairly convinced the guy is full of shit. I thought media blasting was a fairly common practice on jobs like this.
The guy is full of shit. Granted, media blasting can scar a metal surface, but generally not much more that the rust already has. Also, some media is more aggressive than others. On a blasted panel, especially one that has been eaten away at by rust, a skim coat of filler should be applied prior to priming and painting. In some cases, a filler primer can be used depending on the depth of the scarring. About the abrasives, I have ground away many a time and certainly have friction heated the metal with stripping disks and grinding wheels, but no more that by welding a patch panel in place, and the paint has laid down just fine in these areas.
3m purple Strip Kleen discs run cool - I have done many cars this way with a Makita GV 5010 sander - works great and cheap too.
I use the hell out of some 3M brown stripper wheels (I think brown is the most aggressive, if I recall a previous thread)... You'd have to lean on it and hold it in one spot for 5 minutes to make it hot enough to warp the metal. I've zoned out before and cleaned the same spot over and over (I blame my college years), and it's always been fine (I do this fairly regularly). I use 'em on all sorts of things, very effective yet very gentle. I stripped my Model A down to clean metal from the beltline up, only used up about half the disc and did it in maybe 3 or 4 hours (and the original Henry paint is ON THERE! I'd leave it if it wasn't so uglied up). I've used lots of different methods to clean stuff up... I like those the best, but I've never warped anything up with any abrasive, just keep 'er movin' even if it means taking off just a little bit at a time.
If he is sand blasting he will cause more damage. Sand Blasting actually creates heat, I had a 1950 Divco that was media blasted with a media mixture. It worked great except for the areas that had grease build up. After blowing it off, alot of vacuuming, and turning it on the Rotisserie. We just wiped it down and sprayed Acid Etching Primer. You might want to look into a 8" soft pad for thick bondo.
yeah hes full of crap.......ive stripped cars with rolocs before without any problem,as well as a hog,d.a.,wire wheels, even a torch and wire brush. if you fall asleep in one spot with anything that moves you can warp it(hard to do on older cars but not impossible)....as for the paint problem..if you dont actually sand the steel you might have adhesion problems.....but as stated before if you get someone blasting that doesnt know what theyre doing youll have huge problems. if he does get it media blasted id stay away from that idiot
I'd have it glass bead blasted, I had my '51 blasted and it turned out great. The paint was removed in all the little crevises where it's almost impossible to get at with a wheel or chemicals. And if you don't get ALL the chemicals out of all those areas that will be the first place the paint will lift and the chemicals will keep eating away at the metal under the lifted paint. Any "soft" spots in the metal will be blowin out from blasting. It cost's a little more for blasting then to chemical strip but well worth the extra cost in the end. I posted a few pics of my car after blasting, You can see where there was a little filler in places and you can see how clean everything is (firewall fo example) And while the cars out getting blasted it gives you room in the shop to do a little clean up that you desperatly need to do once in a while...
I have stripped 3 cars competely using a sharp 3/4"wood chisel to peel the paint layers down then used 3m strip discs to clean up after. you can heat the sheetmetal enough to bulge it but it will go back to where it started when it cools.
Thanks for the input guys. I just wanted some other opinions because I've used the disks before and never had a problem. Thought maybe this guy knew something I didn't. Ill just stick to using them then. I tried the chemical stripper, and I will never use that stuff again, didn't do much at all.
Years ago we use chemical stripper, was a better option then sandbasting. Always an ugly job, big mess. Clean up was a pain and it seemed there would always be some caught in a seam and come back to haunt you once the new paint was on. Nowdays with the availible stripping discs and media blasting no way would I every chemical strip again. I use disc (cheap and fast) if I'm just doing the outer surfaces, if it's a complete (firewall, jams, interior ect) it goes to a media blaster. Sounds like the blast guy you talked to is spouting BS to make up for a lack of knowledge, I'd stay away from him. Even a media blaster can screw up a car if the operator doesn't know what he's doing, I've had it happen.
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