Shopsmith Forums

mickyd wrote:Well, I made up a quick and dirty prototype of the soda blast system that I referred to in post 1. I wanted to try it for paint removal. I followed the instructions as specified except I didn't have the correct 7/16" diameter clear vinyl tubing or the small OD air nozzle. Instead, the tubing was the larger 3/8" diameter tube and the nozzle...about twice the diameter as that shown.

Stuck the vinyl tubing into a small box of regular baking soda and did a test hit on the nozzle level. The soda BLASTED out of the tube in a cloud. Pretty impressive so I took one of the ER castings that still had a little bit of paint on it and blasted it. In about 15 seconds, I used up the entire box of baking soda!!:eek: It DID remove the paint. There was about a section the size of a fifty cent piece that was cleaned right down to to the base metal.

The hose and nozzle diameter were definitely too large so I picked up the right stuff at Home Depot for less than $10. Tomorrow (actually today since it's 1:45 am), I'll give it a try and let you know how it worked. Also decided that the only way to do this is to use an enclosure similar to a blast cabinet so that I can reuse the soda. I'll make an enclosure using a big cardboard box and some glass for a window.

Picked up a 50 lb. bag of blasting soda from Harbor Freight for $30. The blasting soda is a little more course than the household soda so it should work better.

Not a believer yet but it may just have promise. I'll find out later

JPG40504 wrote:COURSER or grittier or BOTH? Hope the courser runs through the tube ok.

mickyd wrote:More course, NOT grittier.

JPG40504 wrote:Grittier might work Better!!!!! After all you do need an abrasive attribute.

So Mass is more effective than Sharp?

mickyd wrote:Gritter work better?.....agree. Mass more effective than sharp?....I would thinks so.....i.e. shot peening. Those little balls aren't very sharp but it sure takes a lot to stop them. (Newton's first law)

JPG40504 wrote:Methinks you added velocity to the mix. I was assuming an equal velocity for each.

Actually the massier particles would be slower(Newton again-Inertia at rest)!:D

P.S. You trying to remove paint or dent the cast iron?

mickyd wrote:With fluid dynamics, there's a bunch more stuff that would need to come into this picture too to fully describe the "best" abrasion method....

Depends how far you gave to particles to reach speed (to just name a single variable).

p.s. shot peen was an illustration to a point, not my choice of paint removal method...

robinson46176 wrote:I keep intending to try crushed walnut shells.

a1gutterman wrote:I understand that Boeing uses ice pellets.