The Stovebolt Site Forums The Shop Area Paint and Body Shop Sandblasting

I have heard and read that sandblasting can warp body panels.

I have to clean my hood, front fenders, and inner fender wells. What can I (vs. someone I would pay as I do not want to send them to someone to work on) do to be sure that the sandblasting does not warp the pieces? Or is this impossible and I just need to pay someone to have them media blasted?

If it is the heat (rather than the shrinkage caused by "micro" peening of the sand particles) that causes the warpage, can I use a bit of water as I am sandblasting by having someone helping spraying a bit with a garden hose?

Help.

Th warping happens in the larger surface area panels that do not have compound curves or internal supports of any significance. This would include your hood, roof, cab rear panel, etc. The inner fenders, front fenders should be okay to blast BUT you will need to be careful and hit the metal at an angle to prevent the full blast effect. Many people do not like to sand blast due to the warping it can cause. My experience with this is from the blasting I did on some 54 metal. It worked fine on the fenders but I did not use it on the big panels.
To strip paint I would suggest either a DA sander, knotted wire wheel on a grinder, chemicals or media blasting but that would probably be your most expensive option. It is dirty work that takes time.

Many of those things we hear about are blown out of proportion. The process of blasting creates heat and if you continually blast one area long enough it will warp. So a good blaster will take a longer time to do a panel that is 'crustier' than one that has little to remove. It also depends on what he is blasting and its shape. He will probably start w/ a larger 'medium' and depending on your end result use smaller types and grit size. They can blast w/ steel, plastic, sand, glass and nut shells. It also depends on the type of 'medium' used and mostly has to do w/ an in-experienced blaster. You know the kind, student, summer job, here kid go blast that aluminum door panel off that Allard. An experienced blaster should be very able to blast your work, and it will come out fine.

We don't have a media blasting business here in Vero Beach, FL so I decided to buy a compressor and a sandblaster and do it myself. I have not had any problem with warpage because I am using walnut shells combined with Black Magnum. Plus I am only blasting at 90psi. It is a messy, slow process. I created a "booth" by hanging plastic sheets from the side rails of my garage door and the back. roll em down and spray away (use a good mask!).

Sand blasting WILL cause warpage. Yes, you "can" sandblast just about anything and not cause warpage, I personally don't want to take the chance. And YES, I have had a "pro" destroy a couple of 32 Ford doors once.

It is not caused by the heat, it is caused by as Mike said, by "micro peening". A sand blast warped panel is all but trash, I don't want to take the chance personally.

Now, this is with SAND, walnut shells, plastic, soda, these are all different animals and don't have the weight behind them to "peen" it.

Brian

MARTINSR is right sandblasting is risky, if you are going to do it make sure that the person is using walnut, plastic, or something that will remove paint not metal. I also heard soda media works real well.

glass bead is the way to go. It is shot at a lower pressure, and if the shop is good enough to have this material they know what they are doing. plastic medial blasting is good too.... but it doesn't get rid of rust. walnut and soda will not do much for body panels except take a lot more time in labor. Plus, when you get it back, you'll still have to DA the thing for the primer to stick... at least that's what my blaster guy tells me- it makes the metal too smooth. glass bead is just right and leaves a little profile for primer adhesion