Quote:
Originally Posted by Bob Bidonde
Stainless shot treatment is actually a peening process that is a fatigue life enhancement & post forming stress reliever especially beneficial for forgings, castings & machined parts. Not so good for sheet metal. Stainless shot causes a beneficial compressive surface stress.
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I think you are correct in this.
My machine uses paddles (-see 3rd picture) in the bottom of the sump to sling the shot upwards and onto the bottom side of the drum or cage (-depending on what we are cleaning) vs. compressed air. The velocity that my machine creates is less than what compressed air would create. The reason we use stainless over iron shot is because we are in close proximity to a river that runs behind the shop, and if the unit goes for several days without use, the iron shot tended to rust together. Therefore we just switched to stainless steel shot.
FWIW, we have run small items such as oil pans, brackets or fender braces, tail light stands, etc., and it leaves a very smooth surface finish. While we have occasionally run stuff like windshield visors, rear fenders, exhaust headers, etc. in it, we have only done that for short bursts as prolonged run times will generally build heat in thin metal.
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