You asking about the water/sand mix? I've seen YouTube vids that make it look easy but no personal experience...
We use it at work for surface prep on machined castings(thick material) before paint. Works well. I would think a lower pressure/finer media for sheet metal would yield good results. We use glass media. Does make a mess with overspray.
It's not really dustless, it cakes onto the car, and it causes rust. It can warp panels. It also makes a huge mess. I'd never do it.
I would think it would depend on the medium you use with the water. Sand is definitely the worst. When I sandblasted everything, except the quarter panels and roof, of my Sprint back in 02, it turned my driveway into beach front property. What I couldn't sweep up eventually washed away. But it did a hell of a good job. The system they advertise on My Classic Car claims to work on sheet metal with no problems. If I was in the need, I would use their system. I wouldn't base any decision on one video.
that's the system I was talking about. I saw the vids. where they blast fiberglass cars and boats. I saw one where they added a rust preventer. Rust Inhibitor It is specially formulated for the Dustless Blasting process and for our machines, preventing flash rust for up to 72 hours. Use of this product will improve coating adhesion and enhance paint performance all while being non-toxic, biodegradable and non-hazardous. When used correctly by following 4 easy steps, a perfect paint ready surface can be achieved.
This is a place local to me. I have never used them, but I know they do a lot of cars. Might help in your research: http://hdblast.net/
Frank, I had a lot of the parts for my car done with the dustless blasting. It worked great. I did the hood, upper bumper filler, lower front rocker panel and both front fenders. It took a total of 1 1/2 hours do strip it all to the bare metal. There was a preservative of some type in the solution that kept the metal from starting to rust. I just sanded everything good to get back to true bare netal then epoxy primed it all as soon as I sanded it. I have not complaints about it what so ever. Teh nice thing is they will come to your house and do it right in your drive way, really not that messy to clean up afterwards.
"dust-less" yes.. mist-less no. Kinda silly to imagine water based blasting warps sheetmetal unless maybe you use a hot water blaster. lol I don't care what type of blasting you do.. the stuff gets everywhere and it's always messy. Pro's and con's to them all. Personally, I still prefer to chemically strip and minimally grind paint away on wide open areas. Still messy.. harder and longer process with heavier elbow grease involved.. but easy setup, easy cleanup, and you just end up trading visible dust for invisible fumes for the most part. Lots of sweating when it's hot out though.