Body Blasting!!!

[mRclARK1]

This fall/winter I'm planning on finally getting a little more into some bodywork on my car. I'm planning to sandblast most of the surface rust, and small spots starting up on the frame rails and the underside of the car, and cut out and sand down the couple very small spots I have on the body panels. I'm going with sandblasting because I have free access to a sandblaster that I can use anytime. :bigok:

Anyway, who here has any experience with bodywork, and sandblasting rust in particular? I know how to sandblast already, but I've never done any blasting work with metal, only with wood and stone. What grade of sand should I use? I would think something on the finer side to leave as smooth a surface as possible on the bare metal. How much pressure etc so I don't warp/twist any of the sheet metal?

Once I get the rust out, and new metal in... I'm golden, as I have experience with painting and prep work etc... I've just never done any sandblasting/rust fixing before and I'm just looking for any tips or pointers any of you may have. Thanks. :rawk:

EDIT: Thought I was posting in Tech :duh:... mod feel free to move.

[s13rookie]

if you have a lot of paint to remove, maybe you should give soda blasting a try

[mehsilvia]

The trick to rust removal is using media thats abrasive enough to penetrate, but not destroy whats left of the metal underneath.

I happen to have two 50lb sets of media. One is a fine glass bead (great for finish work and wont etch the bare metal) and the other is a bit more of a course black oxide. The later will most certainly take the rust off, as it easily stripped two coats of old paint off my 63 ranchero. Im sure it would be perfect for ya.

You happen to be in SoCal? Id be willing to give you a deal on what ive got and arrange pickup local.

Let me know.

[mRclARK1]

^^^ I'm all the way up in Canada, but thanks for the offer. :bow:

I can probably pick up the same stuff you're talking about from a supplier here, that the company I work for gets there abrasive/sandblasting products from. Roughly what PSI would I want to blast those at? I know that if you blast to high, the metal can deform, and to low, and the blasting won't be effective enough. The blaster I have access to is a smaller one, it's only capable of 150PSI max., but I think that should be by far enough?

[mehsilvia]

I think its gonna depend on how far gone the metal is underneath.

Just run an adjustable regulator at the gun, and start at about 90lbs. I found 90 to be effective and didnt have any issues with warping or pitting.

Good luck and post up some pics of the work and progress.

[mRclARK1]

Awesome... thanks for the help. There are a couple spots where the rust has gone right through the metal. The worst is inside the passenger side wheel well, right above the frame rail on the sheet metal, and then a piece about the size of a nickel on the frame rail itself that's pretty deep. The rest is just surface rust.

It'll be a couple months till I get to this. I'll ressurect this thread when I get to it, and post up pics. I'm just in the "prep" process right now. haha

[RAR]

I had the front/engine bay of mine blasted, it cost about 250 bucks and was well worth it...

Before:
http://www.350z.ws/gallery/d/13843-1/DSCF0095.JPG
http://www.350z.ws/gallery/d/13855-1/DSCF0098.JPG
http://www.350z.ws/gallery/d/13861-1/DSCF0100.JPG
http://www.350z.ws/gallery/d/13864-1/DSCF0101.JPG
http://www.350z.ws/gallery/d/13847-1/DSCF0096.JPG

After:
http://www.350z.ws/gallery/d/13903-1/DSCF0111.JPG
http://www.350z.ws/gallery/d/13908-1/DSCF0112.JPG
http://www.350z.ws/gallery/d/13912-1/DSCF0113.JPG
http://www.350z.ws/gallery/d/13920-1/DSCF0115.JPG
http://www.350z.ws/gallery/d/13940-1/DSCF0120.JPG

Then I hit it with some rust bullet...

http://www.350z.ws/gallery/d/15727-1/DSCF0003.JPG
http://www.350z.ws/gallery/d/15736-1/DSCF0005.JPG

You'll notice its rough - which is what you'll get back with sandblasting... if you want it smooth, try plastic media blasting or nut shell blasting.

Andrew

[ThatGuy]

^None of your links work.

[RAR]

Sorry about that, links should work now.

Andrew

[roycenagger]

Soda blasting FTW.

Sand blasting actually drives the paint into the metal and will rust very quickly as well so you have to cover it quickly (primer/paint).
With Soda, the media breaks up on impact and does not pit body panels and will usually leave the factory zinc coating, etc.
It will pit softer materials though.

You can see the difference in the OEM vs. aftermarket S-13 fenders shown here. The aftermarket one is not coated and shows a lot of bare metal.

http://img53.imageshack.us/img53/2639/dsc00989lf8.th.jpg (http://img53.imageshack.us/my.php?image=dsc00989lf8.jpg)
http://img177.imageshack.us/img177/4560/dsc00992fb1.th.jpg (http://img177.imageshack.us/my.php?image=dsc00992fb1.jpg)
http://img528.imageshack.us/img528/7826/dsc00990xo4.th.jpg (http://img528.imageshack.us/my.php?image=dsc00990xo4.jpg)
http://img528.imageshack.us/img528/2917/dsc00991je0.th.jpg (http://img528.imageshack.us/my.php?image=dsc00991je0.jpg)

-Royce

[jkeisser]

Question:

If you soda or sand blast an entire car + panels, wouldn't the heat created from the blasting warp the metal panels?

I thought about blasting my fenders.. but i just used the aircraft strippers instead.

[mRclARK1]

RAR: That looks really good... thanks for the links.

I'm not to worried about getting it finished beautifully smooth and shiny, I'm only sandblasting the rust on the frame rails and inside the wheel wells... As long as the rust is gone, and it's protected from future corrosion and I can make it look decent with a spray bomb I'll be happy. None of these repairs will be visible anyway. The couple small rust spots on my body panels I'm going to cut/sand away, prep, and then repaint the entire car.