blast media

[2fpower]

I am wondering what blast media I should use in my blast cabinet I picked up at harbor freight today. I stood there in the isle looking at all the choices.... they had crushed walnut, glass bead, alum oxide, steel shot, etc.

Any thoughts. I don't have much rust to deal with, just knock off the paint and surface rust. I plan on shooting them with epoxy primer after cleaning them up.

Thanks for the advice......

 

[kc_chevota]

different type for different applications. haven't tried but iv'e heard that walnut works good

 

[FlatlandTRD]

What about baking soda? Non toxic and protects the metal to prevent flash rusting. I could be totally off, but just throwing that out there.

 

[IBCRUSN]

If you're stripping run of the mill steel pick up some Black Beauty coal slag. The stuff work great on steel and is cheap. If you're blasting sheet metal get the finer grain stuff and be careful you don't blow through or distort the base metal.

 

[MOfj40]

Walnut, soda, and black beauty (coal slag) all work fairly well but they are all one time use media. They work best in an outdoor or blast room application with a pressurized blaster.

Aluminum oxide is great for removing heavy oxidation, epoxy paint, scale, etc but will leave a rough surface. If you're going to use a heavy epoxy primer or rust bullet, etc then no problem. You can run it at 80-90psi so it's cuts quickly and will last for many uses.

Glass bead is a good all around choice. It cuts pretty well, lasts a long time, and leaves a mildly textured matte finish. This is what I keep in the blaster at work. I use 40/80 grit - It cuts rust really well and cuts through the THICK 2 part epoxy paint we use on our machinery pretty well but not as fast as aluminum oxide. I keep al ox in reserve for machine rebuilds etc when we're blasting a lot of parts. If you run 100/140 glass bead at around 60psi I think you'll be pleased with the results. It'll cut fairly quick and leave a smooth surface.

Steel shot is used more for shot peening (work hardening) materials and light rust removal. It's great within a narrow range of applications but not ideal for general purpose use.

If you want to try before you buy I've got 40/80 glass bead and 40/60 aluminum oxide at work (Leavenworth). You're welcome to come by one afternoon/evening and try them out.

 

[2fpower]

Thanks for the awesome advice. I will pick up some glass bead. It looked like about $1 a pound at Harbor freight, so a very cheap way to try it out. I had no idea that walnut, coal and the like were one time use.... that makes it very pricey.

Kelly

 

[MOfj40]

Walnut and black beauty will last a little longer than soda, but still a couple uses and they're done. The big advantage to them is they'll leave a really smooth surface with no etching or distortion so they're preferred by body shops or anyone who'll be doing a base/clear type paint finish.

For a cruiser or industrial/ag equipment that will get a heavy enamel or epoxy finish, the rougher media will last much longer and cut quicker. The heavier coatings will self level to some degree and hide the slight etching that blasting will produce.

To give an example, the 40/80 grit glass bead in my cabinet blaster (suction feed) at 60psi will leave a finish roughly comparable to 400grit sandpaper. If that's not acceptable, make sure and get a finer grit glass bead. I believe that up to 200 grit is readily available through mail order.

Grainger will be comparable in pricing and have better quality media than HF. Have them ship it to the local branch (14790 w 99th in Lenexa) and you won't pay freight. They have coarse through extra fine grades of glass bead usually in stock at the distribution center on Burlington and I've been pleased with the results and longevity when I've purchased their media.

 

[shotgun]

good advice andrew. When did you get the fj cruiser ?

 

[MOfj40]

I bought it a few weeks ago. Got to keep the happy. I'll get it when she's done with it so I didn't complain too much .

I also picked up a yard sale gaucho for my boy. The switches were corroded so I'm rewiring it and prepping for paint. When I get it finished we'll have a tan cruiser triad.