I’ve heard many people recommend sandblasting for the under-body and suspension parts. I’ve also heard many claims that sandblasting body panels can heat them to the point of permanent warping. I can see why soda blasting body panels is safer and could leave a smoother finish but I’m not yet convinced that body panels can actually be “warped” with a sand blaster. It seems like it would be easy enough to demonstrate on a video. Yet all the videos I’ve found show how to avoid warping but never actually demonstrate warping. Has anyone seen this with their own eyes or is it a myth? Send me a link to a video if you can.
I have warped panels sandblasting rust spots. The metal raises if you concentrate on one area too much. I didn’t think it was from the heat. I figured it was expansion caused by multiple impacts of sand particles.
So what you want to see is someone sandblaster a good panel to make it warp?
Its 100% from the heat
Yes sandblasting can warp body panels. While blasting the engine bay on my 68 fastback with an industrial sandblaster my friend thought it would be quicker to hit the roof with the sandblaster to remove lifting paint.He did not dwell in any spots just going back and forth. Result the very well know and respected body shop took one look at the roof and said It warped so badly it needed to be replaced. I saw one panel get ruined that was enough.
Waterlife I don’t think he wants to see someone destroy a good panel. I think he was hoping someone showed what would happen on a scrap piece or junk panel.
No, not really. But from my experience it seems that every body shop has scrap panels laying around.
Do you know what pressure you were using?
Is it possible to lower the air pressure so that it removes paint and rust while reducing the risk of warping? What range of pressures do you recommend?
Below is a picture of my roof after sandblasting, priming and then spending a considerable amount of time and effort making it right again. Trust me, its not something that you want to see. It all depends on the media that you use and the amount of pressure you throw at it as to the severity of the warping. It would be difficult/impossible to get in close enough to see it warp as you blast it, you can barely see it while blasting. After blasting its more of a feel thing. When I did my quarters I stood back 4 feet and took the paint down to the primer and stopped. Sanded the rest.
My compressor gives me 90 lbs for about 1 minute or two then continually roll back to about 65 or 70 pounds where it will settle in, that was too much. Use something fine like crushed glass and on flat unreinforced surfaces back off of the metal with your nozzle or beware.
I’m having trouble deleting previous messages.
I’m having trouble deleting previous messages.
Wow! Thanks CCarney69! There it is. Photographic evidence. So I was wrong, it is a thing. I’ll have to account for that in my restoration plan. I’ve been considering sand blasting the entire car inside and out but now I will have to choose between soda blasting, plastic media blasting and dry ice blasting for the exterior.
I did not know about this when I sent my car to be blasted. It came out straight, so that was good, but I am still getting sand out of it. I would use soda so you could get it clean after blasting.
How about chemical dipping? Don’t know if that’s available everywhere but that would negate the warping concerns, and you wouldn’t have stray sand / media in all the nooks and crannies. There are probably cons that I don’t know about, just throwing that option out there.
From what I have read, there is soda remain(no matter what) and it reacts to the primer/paint
I read that they are leaning to nut shells(walnut) it seems to work best and no after issues
Al
Chemical stripping is good as long as you keep the chemical out of the pinch weld’s. That is the problem with chemicals, they bleed out of the pinch welds down the road and cause the paint to fail. So I’ve heard.
Yes I’ve heard that Walnut shells are good on automotive also. I know that they use them on wood when blasting homes. I know I considered it when I blasted my house to do a color change but decided just to go with sand because it was so much cheaper.