Sandblast Media Question...

[7E-Bodies]

Being OCD meticulous, I think I want to media blast the inside of my gently removed 70 tail light panel. I removed it to replace the trunk pan. I'd like to prep it for applying a nice layer of 24 karat gold, AKA DP40LF epoxy primer. I'm thinking a walnut media or something fairly gentle as it appears to be only a light coat of factory primer along with some over sprayed aftermarket primer. I'm equipped with what I'm sure is a top quality, brand new, Harbor "Fright" blaster. What could possibly go wrong here? Environment friendly media a plus. Any suggestions or guidance appreciated. Also if @Cuda Cody, the author of my painting manual could chime in, that'd be great as well. Thanks in advance.

[70 Challenger Lover]

I just stripped a hood and it was a bear. The original factory primer was surprisingly tough. Because it's not a big flat part like a fender, I would think you could use something stronger like sand with less fear of warpage. I just wouldn't stay in one spot and I'd try to be gentle with it.

The sand I used for other stripping is a fine grade commercial stuff that is specific for sandblasters and come in 90 lb bags. I think it was only like $12 or so and I found it at a special builder supply place. It's very dry and the particles are nice and uniform. The play sand at Home Depot is a very bad choice. Very wet. I also used a commercial grade blaster. The smaller harbor freight units may not get the job done but at least you're working with a relatively small piece.

[Topcat]

Blasting with Sand has risks.

https://www.cdc.gov/niosh/docs/92-102/default.html

[Plumcrazzy]

Personally, I would not use sand. Sand can generate heat which can cause panel warp. I would choose Walnut, glass beads or something along those lines.

[7E-Bodies]

I tried the walnut. Too course to feed through the blaster.

[YellowThumper]

Walnut is more abrasive than sand.
Which is what I use. Being more abrasive, you get in and out of area faster. To me glass bead only works on thick items like brackets. But then are left too smooth and should be roughed up for painting.
Any abrasive will generate heat.

Mike.

[Cudakiller70]

It's not heat that warps a sheet metal panel, it's the peening of the blast media that stretches the metal. If anything cool air is being blasted. The sand or whatever your using is like a mini hammer.

[Cuda Cody]

   It's all in the technique.  Some people can take plastic media or even walnut shells and screw up a panel.  And other people with the right skills could blast with 60 grit aluminum oxide and it would be perfect.

IMO, that panel is going to be a good one to use almost any media since it does not have large open flat areas.  Just do not over work it and you should be totally fine with almost any media. 

[Cudakiller70]

 

[7E-Bodies]

Thanks Cody!

[MoparLeo]

Proper set-up and technique are the key.  Low pressure and constant movement. I use glass beads. Practice on a piece of scrap to get the set-up correct. But, why blast at all ? Why not use Ro-loc pads and an angled air grinder. Much easier to control for some one who doesn't normally use a blaster and easier clean-up. 

[7E-Bodies]

Can't disagree, but I'm doing the inside of the tail panel. Kinda tough getting rotating tools in there. You're idea on a lot of the rest of the car, but tail panel blasted up nicely.

[Cudakiller70]

Like the idea of rotary tools, limits potential damage especially large panels. And with careful blasting in nooks and crannies the probability of success is much higher.