Sandblasting: Pros? Cons?

[Mateo05]

Ok I found a cheap siphon fed sandblaster and have access to a pretty decent size air compressor. But the more I read up on sandblasting from books in the library, they say it warps the metal, but a lot of people I know sandblast their cars to get rid of paint and rust. Not to mention play sand from Lowes is dirt cheap compared to blasting material found online like plastic beads, walnut shells, etc.

[26th-Z]

Sand blasting removes metal just as it does rust, paint, bondo and any other material. Different media is used for different applications. Walnut shell (soft media) is used for softer materials such as plastics and aluminum while glass bead is used for harder materials. "Play sand" is outright dangerous to breath. Sand blasting will leave sand everywhere and is difficult to clean out of a car body. It will warp metal as well as pit the surface. I have read that sand blasting will actually force ferrous ions further into the metal.

I think sand blasting is appropriate for certain applications as long as it is done within a controlled environment like a sand blasting cabinet. I have seen it used successfully in spot areas, but never on a complete car.

[TomoHawk]

26th is right-

When you say "sand blasting," are you talking about using sand as the media? Like he said, there's also plastic, walnut, glass even baking soda! Baking soda is supposed to do the same job as sand, but is much easier to clean out than sand. Probably some other kinds of media too. Try to be more specific.

[EScanlon]

Sandblasting gets a bad rap due to inappropriate use.

The biggest problem with sandblasting warping metal is that too much air pressure is used as well as a highly abrasive media. If you blast too long even with a lower pressure but with a high abrasive media you'll actually heat the metal. Between the heat and the air pressure is what causes the warping.

Properly done you can etch glass, strip off the paint in layers, or even sandblast plastic for texturing.

Media is generally classified with regards to it's hardness, and abrasiveness. Nowdays, they usually just refer to the abrasiveness.

Silicon Carbide, Aluminum Oxide, Glass Bead, Walnut Shells, Poly Abrasives and lastly Sand are the most common. Each has uses that they are best for and other uses for which they shouldn't be used and others where they're simply ineffective.

All of them will perform differently at different pressures.

Check Eastwood's web site and you'll find a bunch of information on the different grades of blasting media and you'll get a better idea of what and how to use them.

Trying to replicate all that info here would take a long time.

Hope this helps.

Enrique

[Mateo05]

Yes very much so, this helps alot. Im new to body work in general and angle grinder with a sanding attachment is taking way too long. So somebody suggested to me about sandblasting and what better people to ask than ClassicZcars.com.

Thanks

Matt

[26th-Z]

Baking Soda!?!?! Gotta try that. Sounds good.

[TomoHawk]

It's been said that sand will get in the holes & crevices and trap water, so you end up making more rust right away. Even if you blow it out, there's still more sand in there. the Baking Soda (granular, not the stuff you bake with) is effective and you can blow it ALL out easier (maybe even wash it out) and there's nothing left to absorb water. It's also better because it's not corrosive if you leave any.

[Mike]

Sandblasting with a siphon feeder and a small volume (inexpensive) air compressor will not usually warp the metal. I sandblasted my entire car. If I was to do it again, I would have done the following:

1) Move everything else out of the garage. Putting up plastic can protect other parts of the garage, but, sand WILL get everywhere. I can guarantee that part.

2) Use a sandblaster that pressurizes a can (this type can warp metal) instead of the siphon feeder. The siphon feed type can take a LONG time. The pressurized can type will make this job go a lot quicker. I ended up purchasing 3 siphon fed systems by the time I was done.

3) Use a sand that does not cause cancer in lab rats. Mine was a silica based sand and has the potential of giving me cancer. Ugh. The things you do when you're younger.

4) Buy a sand-blasting hood from the beginning. I don't care if you think you're gonna take a shower after every session, the sand will still be in your hair, ears, and other places. Buy the hood made from the lightweight white material and if you can afford the suit.... do that too. You'll avoid having sand all over your house.

5) Never plan to drive your car in the rain. If there is sand in the holes and things, they say that water can get in and cause more rust. Hell, don't even let water get near this baby. You spent a long time blasting her to hell.... you don't want to have it ruined by rain!!

Anyway, just some tips.

[viparz]

Do you mean never drive your car in the rain ever again, or just while it is stripped

[TomoHawk]

I think hew means while there is any bare, unprotected metal. After blasting with sand, there is some (sand) still in the cracks & crevices, and is almost impossible to get totally out, so you wouldn't want to get water in those cracks & crevices until you absolutely get it all out and paint or whatever.

[Mike]

Actually, I meant to never drive it in the rain ever again.. Why? I spent $6,500 on paint, bodywork, etc... This baby only comes out when it's sunny. :cheeky:

[26th-Z]

I'll confirm that!!! I spent $6500 on Her Majesty in 1991 and I'm about to do it again. And she's been in storage for five years!

I guess if you are going to take your car down to a stage that you can sand blast, you won't abuse it so much by letting it sit out in the rain. Down here, it's not good to let the car see sunlight.:classic:

I might suggest that a car completely stripped is the best candidate for sand blasting because the mess can be cleaned up the easiest. I aggree it's too messy to blast areas without taking the car apart. And there are areas in the frame that would trap media and be difficult to clean out.