Glass Bead Blasting Rims

[JimC2]

Not fun. I should have them ready to prime by Tuesday.

 

[ab705]

I blasted about 10 rims before I got down to five that I liked well enough to use on my M37. I used a pretty aggressive media on the rims (aluminum oxide.), but it still took a long time and was quite tedious. I currently have glass beads in my little blasting cabinet, which I prefer for doing more delicate work or when working with thinner metals.

 

[JimC2]

I'm using 80 grit for the rims

 

[ab705]

I think 80 mesh is what I have now in glass beads, but the same 80 mesh size in aluminum oxide is more aggressive, since its density is greater, the particles are quite angular, and it doesn't break down as quickly glass beads, which have what I would call 'moderate' longevity. In my experience, glass beads are gentler on thin metal and for items that will require a nice smooth finish.

If I have some hefty items with heavy rust or thick layers of paint to remove, and if some slightly noticeable surface texture isn't objectionable, I'll buy a couple of bags of coal slag, as it's cheap and very aggressive. It breaks down faster than most of the other media that I've used, but it does work quickly. If the weather is decent, I'll use it outside with a blasting attachment for my pressure washer (11.5HP engine and pump rated at 4,000 psi), the combination of which is extremely aggressive, albeit VERY messy. I wear a full set of personal protective gear.

Garnet is a good compromise. I currently have a 50-lb box of garnet grit waiting for when the current load of glass beads have finally broken down too much.

 

[JimC2]

Thanks for the info.
The glass beads are quick enough - But the air compressor doesn't have a water trap, and after a while starts putting enough moisture into the blaster that it clogs the media.

 

[ab705]

But the air compressor doesn't have a water trap, and after a while starts putting enough moisture into the blaster that it clogs the media.

Somewhere on my never-ending "to-do" list is the installation of an aftercooler/condenser for my compressor, which is a good way to dry out compressed air. In the meantime, I've been getting by OK with a couple of water separators in combination with the relatively dry air in my shop (I have a dehumidifier to help keep my equipment from rusting).

For my plasma cutter, I have a desiccant gel air line module mounted on the plasma cutter cart. I found that desiccant gel is actually quite cheap if you order it in bulk...like a 5-gallon pail of it...and to a limited extent it can be dried out and re-used, although it's cheap enough that when it changes color I just replace it.

 

[JimC2]

Isn't mine to modify. I'm working at the shop of a Contractor friend.
Air Compressor quit about an hour ago, so I've called it a day.

 

[JimC2]

Well, not quite a day. I'm cleaning paint and rust off one of my headlight bucket rims. There are a number of pinholes and deep pitting on the back side. I can think of 4 ways to repair it and am leaning toward solder.

 

[JimC2]

After getting the headlight rim cleaned up, there are some relatively large areas on the inside where I can't dissolve the rust deposits, so I'm going to punt on the solder and go with glass reinforced bondo thinned with a bit of extra styrene to make it flow better.

 

[87cr250r]

Do you have an oven that can fit these parts? Bake them at 500°F+ which will burn or harden any coatings and make them much easier to remove by media blasting. Dunking them in a heated sodium hydroxide solution will have similar results but requires disposal afterwards.

 

[JimC2]

Thanks