Any tips for sand blasting?

[Kizilsakal]

Hi everyone

I have stripped my car fully and now I will take it to sandblasting. Any tips about things I should be careful about? Do I need to do any special preparations?

 

[Nicad]

Don't do Sand blasting on body panels. Glass bead for removing rust, plastic media for removing paint.

 

[jmackro]

Don't do Sand blasting on body panels. Glass bead for removing rust, plastic media for removing paint.

Yes, media blasting is an art - make sure that whoever blasts your e9 knows what they're doing (hint: the person handling the cash register in the front office is usually not the person who actually blasts your car).

Media blasting generates quite a bit of heat from the friction of the media against the paint & metal. Hold the spray in one place for too long, and you get a warped panel. Plastic media generates less friction heat than sand. But sand is OK to use on heavy parts, such as the undercarriage, which are less prone to warpage.

 

[Nicad]

I have done a lot of plastic Media blasting on a World War II Bomber (Avro Lancaster). It really just strips the finish and leaves behind a clean surface that is undamaged. This is on aluminum mostly. Impressive stuff.

 

[Peter Coomaraswamy]

Better buy a good vacuum and plan on hooking up a good drying system to your compressor because sand, walnut shells, whatever will find its way into every little hiding place :-( ...but as said below, it sure works wonders if done correctly!

 

[calshamus]

I'm a bit confused. Are you sandblasting it yourself or taking it to be sandblasted? In either case, based on your question, I'll assume and recommend the later.

In picking a sand blasting shop, I'd skip ahead and determine who going to do the body work and paint. Once you know that, then I'd take it to a place that body shop recommends since ultimately they're responsible for the finished product (and quoted price) and won't recommend one that might heat warp your panels or not finish out the corners (jack up the body work/ prep costs).

 

[Kizilsakal]

Thanks Guys

I wont be sand blasting myself, it will be done by professionals but as in most things over here many small shops don't do a good quality job. if you want to get something done correctly you have to stand next do the guy and tell him what to do. so I have to tell the guy not heat up one portion of the sheet metal.

I read in a magazine that dry ice blasting is the miracle thing these days. the dry ice evaporates and leaves much less mess. it doesnt heat up the panel (its the opposite actually) the only mess left is the paint removed.

But there is a lot of body filler on my car. up to a cm in places. I am wondering if walnut shells or dry ice can remove this stuff?

 

[G]

If your going with glass beads suggest you strip the paint first . I used glass beads on my 2002, it worked great on the rusty areas but where I got lazy and did not strip the paint it took forever.

 

[jmackro]

In picking a sand blasting shop, I'd skip ahead and determine who going to do the body work and paint. Once you know that, then I'd take it to a place that body shop recommends since ultimately they're responsible for the finished product.

That's an excellent point. The body shop might even say "don't bother media blasting it - we'll just sand off the old paint"

I wont be sand blasting myself, it will be done by professionals but as in most things over here many small shops don't do a good quality job.

Where is "over here"? I'll never understand why posters are so secretive about where they are located. Divulge your location, and someone here on e9coupe.com who lives in your area might have a recommendation for a quality media blasting shop.

 

[John Buchtenkirch]

DON'T sand blast it.

Sand blasting is for cleaning iron lawn chairs. Glass beading is for aluminum engine parts. Aluminum oxide is what you should use on rusty auto body panels unless your just looking to remove the paint where any of the media blasting companies will probably work fine. Despite of what most people believe the heat buildup isn’t the cause of the warping, it’s hitting it with 10000 little hammers (OK, actually abrasive particles) that stretches and domes up / warps the metal. I blast several of my customers panels in my cabinet every month and NEVER warp any of them…… here is why.
#1 I use aluminum oxide, it’s probably 1/25 of the weight of play sand so smaller lighter hammers just do less damage than heavy hammers if that makes any sense.
#2 I never blast straight into a panel, always 20 to 30 degrees off of parallel, glancing blows are just less likely to stretch the metal but they still cut paint & rust.
#3 I turn down my blast pressure to 60 PSI on larger flat panels.
Personally I wouldn’t let anyone blast my car unless they had a history of jobs on antique cars, you absolutely don’t want the guy that does industrial steel or lawn chairs.
GOOD LUCK ~ John Buchtenkirch

 

[bimbill]

Media blasting is a more correct term

The shop that stripped my car used plastic media to remove the paint and used garnet only in areas where there was rust scale which were fortunately only a couple in the floors and one in the trunk.

This photo is one of my favorites so far. It is the underside of the hood and if you can make out the faint lettering, I surmise it is the information from the steel manufacturer that was applied before Karmann stamped the panel. I believe only plastic media would have removed the paint and left that behind.

As others have said, find a business that blasts cars for restoration. They might also do industrial blasting but they'll know the difference.

http://www.e9coupe.com/forum/attachment.php?attachmentid=6513&stc=1&d=1352227902

 

[Kizilsakal]

That's an excellent point. The body shop might even say "don't bother media blasting it - we'll just sand off the old paint"



Where is "over here"? I'll never understand why posters are so secretive about where they are located. Divulge your location, and someone here on e9coupe.com who lives in your area might have a recommendation for a quality media blasting shop.

Thanks for all the replies guys

You are right sorry about that. I am in Istanbul Turkey, I must have mentioned this in my earlier messages but it's not like everyone reads everything. there are only 3-4 e9 coupes here in turkey. only one other CSL I know of and that came from Germany last year already restored.

We have some really talented body guys and mechanics here but I have never found anyone who can do a really good restoration job. that's why I have taken on the dis-assembly myself and I will be putting together the car at the end myself. There are no shops for acid dipping or rust proofing by immersion coating. That's why I have to find out whats best for the car myself. I am guessing nobody has experience with this dry ice blasting stuff.

The state of the car is really bad so i will not let anyone paint another coat over it. I want to strip it back to bare metal, which will also help me with its history as I will see all the pieces welded on. http://www.flickr.com/photos/kizilsakal/8113573979/in/set-72157631829812233http://www.flickr.com/photos/kizilsakal/8113573979/in/set-72157631829812233

All the restorations I see here medium to good quality jobs but nothing perfect. I am aiming a little higher, hopefully I wont be embarrassed but my car should at least perfect panel gaps and solid rust proofing

Maybe I will be going in the direction to do what singer does to 911 http://www.singervehicledesign.com/ or mechatronic to w113 pagoda SL http://www.mechatronik.de/welcome-t...sic-specialized-on-mercedes-classic-cars.html I havent decided yet.

Back to the media balsting subject, what is the best way to remove paint other than acid dipping, since it looks like I should remove the paint and body filler before media blasting?

 

[Kizilsakal]

Personally I wouldn’t let anyone blast my car unless they had a history of jobs on antique cars, you absolutely don’t want the guy that does industrial steel or lawn chairs.
GOOD LUCK ~ John Buchtenkirch

Thanks John

I am thinking maybe I should get a cabinet to do this myself too.

 

[Nicad]

Why not just use chemical strippers? You can do that at home and without special equipment.

 

[G]

For paint removing I've successfully used "Aircraft paint remover" on 3 different cars. It comes in a gel, spread it on with a paint brush wait a few minutes and paint starts to bubble.

Found this on youtube......... http://www.youtube.com/watch?v=CoqePrVvCHk

 

[decoupe]

I remember the discussion mentioned putting 2mil poly over the gel to keep the evaporation to a minimum so the gel had time to work.