How to Prevent Warping Sheet Metal During Media Blasting
Mark SimpsonDescription
Media blasting sheet metal can easily lead to warped and dented metal. Mark Simpson demonstrates the proper technique to use on sheet metal parts to ensure warp-free blasting.
When media blasting, you actually introduce heat into the, into whatever you're blasting, it's the abrasion process that causes friction. This can be a problem with working with sheet metal, sheet metal will actually warp as too much heat is introduced into it. So the way to get around that is to hold your blasting gun at an angle, usually, you know, not too tight of an angle. Otherwise it'll, the media will just skip across the surface but about, you know, somewhere between a 3040 degree angle, you're gonna come at it and then make fast sweeps. You'll just be taking a little off each time and then change the direction and go at it in fast sweeps like that. That way you're not forcing a lot of heat into one area. You're evening it out and then you're also uh attacking those rust pots and the uh some of the rusted areas at different angles. So it'll actually clean them all out with that. Let's go take those pieces of the cabinet and we'll show you how it's done. Do we begin the process? We just kind of lightly going over it as you can see it's not as fast as if you just directed the spray right on it. But what we don't want to end up with, there's a piece of warped metal that's gonna take 10 times longer to straighten out and applied body filler and everything else to try to give it back to the original sh and it takes a little time. But, uh, what, as I tell everybody, it's a hobby, not a race and applying thick strokes, not like concentrating heat in any one area for too long. Again, change the angle, especially when you're in heavy pitted areas like this we have here. We just gradually keep working it. Ok. Ok. Ok. We'll take that out of the cabinet, see what that looks like. As you can see it cleaned up the surface very nicely. It, uh, it takes a little longer to actually clean rust and paint off of sheet metal without warping it, but it's best. It's time well spent and, uh, having had to straighten out panels that guys have blasted and warped all the heck. It, uh, it really pays to take the time. Come at it at an angle and clean it up real well. This is coming along nice. Let's get it, uh, back in the cabinet, we'll finish it up. We'll have it on the oil hot rod in no time.
What about the backside of the piece you're blasting?
Temperature is not the reason for sheetmetal warping. I can demonstrate this in my vaporblaster where I can bend sheetmetal and the temp is barely 50 degrees but when you „hammer“ sheetmetal from above you stretch the surface on one side and it bends. Now if you „hammer“ the backside you can straighten it again to some extend. Now „shooting“ at a shallow angle only „scratches“ the surface but does not stretch it and that avoids bending. Greetings, Bernhard
Proper selection of abrasive and pressure is important consideration as well as variations in material thickness and types.
Or use a new laser rust remover......ten times faster and even gets the spots........