Dustless blasting?

[BK911]

Getting ready to put my tub in for media blasting.
Just talked to a guy who does dustless blasting.
Its a water/sand mix mixed with a little rust inhibitor.
He claims the water keeps the panels cool so they dont warp.
Anybody have any experience with this?

[jpnovak]

Had mine done a few weeks ago. So far so good.

Project Minne - A Saga of a 72.

If you have it done at home it will create a beach. I had several inches of media everywhere. I shoveled it, dried it and spread onto the yard as suggested. I have lots of clay in the soil so this will help.

Make sure they rinse well. Any pockets of sand will stay wet and create surface rust. Its easy to clean but more work. Dry the car as fast as possible. I used the wet/dry vac and leaf blower to speed things up and then parked the car in a garage with two floor heaters and fans in place overnight.

After I wiped down the tub with a rust inhibitor that I make myself.

Its the only blasting process I have seen that will actually remove undercoating. They used coarse media on the bottom and medium fine on the outer painted panels.


Did I mention it makes a mess?

[Cook&Dunning]

Wow, you must have some mighty nice neighbors. I get spreading the sand around your property, but all the paint, undercoat and other crud that came off with blasting gets buried, too? That would be a deal breaker for me - at least the doing it on my property part.

[BK911]

Thanks for the link Jamie. Very nice work, and extremely motivational!!!!

[Trackrash]

Would dry ice blasting take off paint?

[G50911]

if it's the dustless blasting i know, they don't use sand. it's recycled bottle glass. it also doesn't disperse as much media as traditional blasting does. do you know which company you're going with?

[BK911]

A local company called Tennessee Metallizing.
They use the green machine.
Took some parts there for blasting and powder coating and saw a first gen camaro recently done.
Almost ready to get my 71 tub blasted, so asked for more details.
Sounds interesting.

Also, ever hear of metallizing? Basically spraining liquid metal on a surface. Way cool stuff.

[Tim K]

Originally Posted by BK911

...

Also, ever hear of metallizing? Basically spraining liquid metal on a surface. Way cool stuff.

I've seen it on the interwebz but I don't believe it is a viable alternative to proper rust repair, if that's why you're asking.

Share pics of the blasting process if you can.

Tim K

[Daves911L]

Recently had a big pile of loose 356 panels done with the dustless blasting. VERY DISPLEASED. I heard the same spiel about the water keeping it cool so no warping. Regardless, a pair of coupe doors, and a pair of roadster doors got the s**t warped out of them. The rust inhibitor? Knowing what I know now, I wouldn't use this on any panel with an overlap joint (and there ain't many that don't have those!) That hi pressure water stream blew water/grit/chemicals deep in the crevices, and within a few days I could see a little bloom around the seams. Wish I hadn't done it. Made a LOT of new work for myself. Run, don't walk, away. That's my advice.

[Das Schnell Ei]

Im going to have one of my tubs done in a week or two... going to be glass and water. I will post the results

[mattC2993]

Sandblasting causes a compressive residual stress on the surface of the metal which causes the warping. Don't use sand on large panels.

[Daves911L]

Dustless blasting is promoted as the latest miracle cure. But the "dustless" part of it is just a convenience for the operator, allowing a guy to offer a mobile service. Adding water to the process is good for business, but bad for the metal being blasted.

I watched for a little while when the guy was working on my panels. Maybe rather than warping (compressive residual stress sounds more plausible than heat), he just flat out dented them. The blast of abrasive/water slurry out of the nozzle must carry the force of a sizable hammer. In this regard, the skill of the operator is a major factor. But that is true with traditional blasting too. Someone who knows what they are doing with a blaster and various media can darn near clean a Rembrandt. The problem is that most don't know what they are doing, or like the guy that did my stuff, just bought a business opportunity and is trying to recoup his investment as fast as possible.

[chris_seven]

Originally Posted by Daves911L

I watched for a little while when the guy was working on my panels. Maybe rather than warping (compressive residual stress sounds more plausible than heat), he just flat out dented them. The blast of abrasive/water slurry out of the nozzle must carry the force of a sizable hammer. In this regard, the skill of the operator is a major factor. But that is true with traditional blasting too.

Quite true - heat has nothing to do with warped panels with any media blasting it is just down to simple kinetic energy.

The residual stress problem is subtly different and when the vehicle is driven any vibration that can provide an activation energy can allow residual stresses to relax and allow a panels to distort.

There is a very famous Jaguar Mk2 that was used on a UK detective show that was restored close to my home.

The shell was media blasted and after paint and being driven for a couple of weeks the roof developed very small 'waves' in the paint.

It was re-painted and 'waves' came back.

It now has a vinyl roof and they guys who restored it never blasted a roof again.

[Dpmulvan]

It's just a gimmick used by those that don't have a proper room for media blasting. Water and bare metal? Cmon.

[mattC2993]

Silica sand is extremely hard and sharp which is why it does so much damage. Perhaps smaller grain size does less damage (#7 and smaller) This also explains why it is more effective on rust.

[scotty b]

I own this system. I bought it simply to allow me to blast customers cars, as I have in the past paid others to do the blasting and have had bad issues. The system works great on exteriors only.

First : It WILL NOT warp a panel. The first thing I did was to take a 914 trunk lid, and put the nozzle directly center where there is no subframe and go full blast for a minute if not more at less than 2" off the lid. Anyone that f*cks a panel blasting with this system did not create the damage with the blaster. Guaranteed

Second, I have now done a 914-6 inside and out, a 911 inside and out, a 31 Ford inside and out and a 40 Ford inside and out, and can tell you I will probably NEVER do another car inside. Engine bays, interiors trunk etc. Anywhere that has corners, crevices etc will pack the media in and just keep building it up. No matter of rinsing will get it out, you have to go in with a screwdriver or other implement to dig it out, and by that point it has sat there so long it will have a very slight surface rust forming

Third: the chemical added to the blasting water and the wash down is called Holdtite. It has been used in the marine industry for years. It is not however effective when the temp and humidity is high, and it doesn't seem to do much when the temps are cold. I assume this has to do with the rate of evaporation of the water. I have blasted and rinsed panels before that lasted months before an y sign of surface rust popped up, and I have blasted panels before that had signs of rust within an hour

Fourth: I know the O.P. is planning to pay someone else, but anyone thinking about this as an investment to your business, or starting your own blasting co, need to know this thing LOVES air. I have a fairly large 3 phase, 10 h.p. 2 stage compressor and it can't keep up with the blaster. Anytime I need to blast I have to rent a tow behind diesel rig that puts out 185 CFM

Fifth : the residue left is broken down glass particles and colored water. You don't end up with chunks of paint, and rust grit all over the place

sixth : the companies videos are pretty misleading, and they themselves can't seem to help me resolve the surging, clogging issue I intermittently have. In hind sight I wish I had saved the money kept farming the blast work out to someone worth a damn

[mattC2993]

So you are using glass bead or particulate and not sand. That is a big difference in itself.

[sundevil64]

The media they use is recycled crushed bottle glass. I use it in my cabinet and I am happy with it for that use. It is very consistent in the granule size for a more consistent flow in my cabinet. In my experience, a large part of preserving the substrate with blasting has to do with the pressure used.

I was at JPNovak's blast event and they were very attentive to the pressure. Any areas with exterior body panels was run at 40psi and undercoat was run at 65psi. I think he will be okay.

[scotty b]

Originally Posted by mattC2993

So you are using glass bead or particulate and not sand. That is a big difference in itself.

Yes the " dustless blasting " system is designed for the recycled bottles as others have mentioned. I'm fortunate to have one of the facilities that does the bottle crushing about 20 minutes away so I can go get it direct form the manufacturer, but even at retail price it is still quite a bit cheaper than Black Beauty or the standard glass bead I have in my cabinet. Plus the glass is so pretty when the sun hits it

[Cairo94507]

Scotty is "artsy" like that.....