Picked up a used tub for my 77 cj5 project. I want to take it down to my local blaster but I want to make sure what they use is gonna be ok. Also the PO had the inside rhino lined which I want removed. I know they blast everything with black beauty. This is what I found on the net do you guys think it will be ok???
Black Beauty Abrasives
Black beauty abrasives also known as coal slag, black diamond, black blast and boiler slag is an inexpensive media. It is one of the safer forms of abrasive media, containing less than 1% or no silica. Black beauty media also produces little dust, however, may release hazardous air pollutants (HAP) into the surrounding air.

Black Beauty abrasives are made from crushed liquid coal slag from utility boilers. The abrasive contains iron (Fe), Aluminum (Al), Magnesium (Mg) and Calcium (Ca). The media comes in sharp angular grains ranging in many sizes including coarse, medium, fine and extra fine grained. The coarser grains can be used to remove heavy rust and provide a high degree of profile, good for coating attachment and bonding. The finer grains can be used for cleaning surfaces and for smoothing surfaces. The media is used on many applications including steel, buildings, railroads and bridges. Coal slag is a fast-cutting media with a hardness of 6-7 on the Moh's hardness scale. The media is non-recyclable.

Moh's Hardness Scale for Abrasive Media
Walnut Shells 2.5-4.5
Clear-Cut 2.0-2.5
Polyester Type I 3
Urea Type II 5
Melamine Type III 4
Glass Beads 5.0-6.5
Silica Sand (Quartz) 8
Garnet 10
Zirconia 11
Aluminum Oxide 12
Silicon Carbide 13

It will probably warp the sheetmetal, you need to get it blasted with either crushed walnut shells or acid dipped. If you want, take them a small piece of sheetmetal and try it as a test piece. Tim