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sandblasting the frame

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Haven't done a lot of "sand" blasting, but I've done plenty of blasting using iron grit according to NACE standards.


The "frame/unibody" will require a different medium than the body, or more accurately the exterior of the body.


Iron grit is best. Most commonly required by specs for bridges, underground pipes, and other infrastructure. Its reusable although it gets smashed into dust eventually. On any part that requires a smooth surface for finishing, like a body panel, the best medium is the smallest. Almost dust sized particles are required for a smooth blast, and as long as you've got a decent gun and at least 90 psi, actual iron dust would be perfect for body panels or any other parts requiring a smooth finish.


On the frame and underside, it doesn't matter as much, in fact the profile created by larger grit will actually help paint adhesion. Don't bother with etching compound etc, its hogwash. Most paints bond physically, not chemically to metal. So you want a micro jagged profle, the sharper the profile on the metal, the better the paint will adhere. So yes you'll be better off blasting the heck out of the frame with a G25 or so sized grit.


Also, what are you blasting with? Dry is best if you're wet blasting it just defeats the purpose of corrosion protection and you might as well not prep it and slap POR15 on it and be done. I just don't get wet blasting.

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Click on my build link in my sig and you can see what I did.


I used a cheap Harbor Freight 20lb pressure blaster. I added a moisture trap to the air inlet to prevent the media from clogging the pot. You will need a big compressor or a lot of patience, I had a little of each.


I used Black Diamond media, about $7 for a 50 lb bag at the farm supply store. It is coal slag. Black beauty is a similar product I found at the hardware store, but it was priced a little note. I liked the 40/60 grit best. Tried a bag of 20/40 but it would clog my nozzle.


Have respirators, goggles, gloves and a long sleeved shirt. A hat helps too as well as ear plugs. You will understand why once you are under the truck with the nozzle....


I ran at least 600 lbs of media through my blaster. I bought 300 lbs of Black Diamond to do my truck and reused it. A tarp under the truck will capture most of the media. If you want to reuse it, buy a kitchen strainer that will fit inside the funnel for your blaster. Makes reusing the media really easy and efficient.


Make sure your cell phone is no where near the blasting site. The media dust will get into the speaker and ruin it, it will sound like you are under water. Ask me know I know this.......

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  • 3 weeks later...

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