Sandblasting an E30?

[Cabriolet]

thx man

[ksjdan]

Would using duct tape and cardboard box to tape up the loose gaps and windshield rubber prevent most dust and damages?

[willworkfore30s]

Likely not. Think about what the media blasting does... It blasts away paint and bondo and rusted metal all of which are attached to the car fairly well. If you put your hand in front of a blast gun it can blast your skin off. Its no joke and will inevitably get under the duct tape and cardboard or just blow them away.

[nrubenstein]

Would using duct tape and cardboard box to tape up the loose gaps and windshield rubber prevent most dust and damages?

No. It would rip the duct tape off promptly.

Blasting will not save you time or effort. Also, you don't want to go to bare metal if you don't have to.

The quick way to paint is to sand the existing paint to give the new paint something to grip. You only go to bare metal if the car has had multiple resprays and/or there is serious paint structure failure. Factory paint, especially, will give you the best possible surface to paint over when prepared properly.

[Cabriolet]

I would say 1/2 of this stuff is true. and i have first hand knowledge and have done this to an E30.

Nothing will fully stop the dust from getting into the car. never have a car sand blasted, make sure it's "media" blasting and that media needs to be garnet.

yes the ducttap will stop stuff. i asked them to media blast my car but needed the door vins left 100% intact. they did 100% leave the door tags perfect, not a scratch on them. all they did was tape over them. all the plastic clips in the engine bay survived w/o damage. all of the plastic door clips survived.

media blasting gets all the rust and corners very well. but you have to remove all glass and try to seal the car the best you can. the car has to me manually sanded smooth because the media blasting leaves it rough.

manual stripping is 2x more expensive and has no real mess afterwards and the side glass can be left in.

[ksjdan]

Thank for the clarifications. I have some rust on the car, and want to tackle it once and for all. I need to blast both inside and out for passenger fender (keep original body) to get all the rust off, and also put some time into driver door rust as well. If it wasn't for the rust and some previous bondo work, id just drop it off at Maaco, but its not the case.

Also wouldn't the rough surface make ideal surface to lay primer on? Its already semi-sanded right? ;) thick layers of primer and wet sanding that instead of the body. I fear if bare metal is wet sanded, it might trigger rust.
So maybe something like washing the body with grease remover and spray a layer zinc formula to prevent rusting. Then start with body work and so on.. Does it seem like a decent strategy?

[Cabriolet]

no it's way too rough to paint over that way.

[nrubenstein]

Thank for the clarifications. I have some rust on the car, and want to tackle it once and for all. I need to blast both inside and out for passenger fender (keep original body) to get all the rust off, and also put some time into driver door rust as well. If it wasn't for the rust and some previous bondo work, id just drop it off at Maaco, but its not the case.

Also wouldn't the rough surface make ideal surface to lay primer on? Its already semi-sanded right? ;) thick layers of primer and wet sanding that instead of the body. I fear if bare metal is wet sanded, it might trigger rust.
So maybe something like washing the body with grease remover and spray a layer zinc formula to prevent rusting. Then start with body work and so on.. Does it seem like a decent strategy?

A "rough" surface to lay paint on is something like 200-800 grit, depending on the paint. And really, 200 grit only with an orbital, which is very different from 200 grit by hand.

Blasting sand will not give that kind of finish.

[krazcustoms]

Even if you sandblast, you will still have to sand the surface anyway. Some of the sand will actually embed into the surface of the metal kinda like when you throw a snowball at something and part if it sticks there.

Personally, I would chemical strip it and only blast the rusted spots.

Step 1: Double-tape all seams and areas you don't want stripper on.

Step 2: Apply chemical stripper.

Step 3: Remove chemical stripper with a putty knife, preferably plastic.

Step 4: Dip some red Scotch-Brite pads in a bucket of water and lightly scrub the entire stripped surface to neutralize the stripper residue.

Step 5: IMMEDIATELY blow the car off with compressed air to dry it as quickly as possible.

Step 6: Sand with 80 grit on a DA (dual-action sander)

Step 7: Sand with 120 grit on a DA

Done. Ready for primer, sealer or what-have-you. Epoxy primer would be best, THEN bodywork.

All 7 steps shouldn't take any longer than it would take just to clean up the mess you'll make from sandblasting.