|Warped Aluminum Panel|
Abrasive blasting is used for many different purposes including cleaning, stripping paint or rust, peening and preparing a surface for a coating (among many others). Usually, there is no need to be concerned about changing the dimensions of the material but sometimes care does need to be taken when blasting thin metals (i.e., auto body panels).
The picture above shows a thin metal panel on the right before any blasting. The same piece on the left was blasted with Glass Beads. It is quite obvious that the blasting process warped the metal. This was caused by heat generated during the blasting process in the spot that was being blasted and no heat in the areas nearby.
Care must be taken in the selection of media used for blasting. Aggressive media like Aluminum Oxide Grit or Glass can cause heat during blasting. While effective performing media, when working with thin metals these media can destroy the metal in the process.
Media such as Walnut Shell Grit and Plastic Abrasive Media are often better choices where warping is a concern. These softer media will also strip paint (albeit more slowly) with a much lower risk of damaging the underlying metal.