Just remember sandblasting sheetmetal "can" totally distroy it. I am not talking "darn I have some more work to do" kinda damage, I am talking "darn, I have to throw the panel away" kinda damage.
The sand acts like little hammers pounding the surface of the metal and stretches it. DO NOT sand blast any outside sheetmetal surfaces.
The heavier the particles, the more damage that can result. You be the judge on what sand to use.
