Bodywork, Paint, Interior, Trim, & Wiring

discussions about bodywork, paint, interiors, trim, audio, electrical components, wiring, etc.

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tr8todd
Todd Kishbach

(372 posts)

Registered:
12/04/2009 07:42AM

Main British Car:


Dustless blasting
Posted by: tr8todd
Date: September 22, 2019 07:23AM

Don't do it. Don't even think about it. Warped my panels my TR8 coupe, and left sand everywhere. The clean up at the house was horrendous. Rust started forming almost immediately. Destroyed a hood, trunk and the roof panel. Had to cut out the roof and install one of those sliding folding Webasto tops. Finding a trunk lid was easy. Finding a TR8 hood that wasn't rusted was another story, and an expensive one at that. Flash forward a year later and I'm finally ready to paint the car. Still getting sand that miraculously keeps appearing despite many many hours of hitting the car with high pressure air, multiple complete hose downs with water. Last coat of primer sealer had some sand in it. No problem, scuff it before color coat anyway. Spray color on jams, underside of hood and trunk, inside trunk, and engine bay. Get a little sand on fender tops, and tops of strut towers, no problem. Clean everything up and go back in a week later to color the whole car. First coat, great, second coat goes down as smooth as the first, and then I see the car from a different angle, sand sitting on top of the paint in a few areas. Worst spots are vertical sections at the backs of the rear fenders and along the tail light panel. I'll give it three days or so and then hit it with some 1000 grit and see if I need to give it another dusting of color. At least the car is single stage white, so touch ups will be easy. Yesterday I was watching a TV show that rebuilds old Japanese cars. They were chemically stripping a car, and the guy says something about how they know now not to blast a car as it just warps the panels. Process might be great for pickup truck frames, but not on thin paneled sports cars.


mstemp
Mike Stemp
Calgary, Canada
(207 posts)

Registered:
11/25/2009 07:18AM

Main British Car:
1980 MGB Rover 4.6L

Re: Dustless blasting
Posted by: mstemp
Date: September 22, 2019 08:56AM

Sorry to hear iof the poor results. I thought it looked like a great method. 20 years ago I had my MGB shell plastic media blasted (used air) No warped panels from that technique. Sounds like your dustless technique still uses sand.as the media and maybe too high a pressure? What distance from the surface did you use?



Edited 1 time(s). Last edit at 09/22/2019 09:03AM by mstemp.


tr8todd
Todd Kishbach

(372 posts)

Registered:
12/04/2009 07:42AM

Main British Car:


Re: Dustless blasting
Posted by: tr8todd
Date: September 22, 2019 06:52PM

Wasn't me. Actually paid a professional to do it. Spent the last year off and on trying to get it ready for paint. Saw this current stretch of perfect weather coming up so I decided to prep and paint another TR8 as well. Started sanding down that one last weekend. Sprayed the sand blasted car yesterday and the second car today. So the math works out to a year of body work on a zero rust car compared to a week on another zero rust car. To be fair, I also prepped and painted the engine bay, interior, and trunk on the sand blasted car as well as building roll bar inside it. Rolled the fender lips, and did a few other small mods. Adding the support structure for the folding roof took some serious time.


88v8
Ivor Duarte
Gloucestershire UK
(758 posts)

Registered:
02/11/2010 04:29AM

Main British Car:
1974 Land Rover Lightweight V8

Re: Dustless blasting
Posted by: 88v8
Date: February 01, 2020 04:48AM

Bit late but.... it can work. I had the hood of my TR6 blasted by plastic media. No warp at all, and that's a big panel.
It depends on the operator. Too high pressure, too near, too impatient, will do irreversible damage.
The company had been doing the job for a while, were recommended to me. I took the panel to them and it was done in a closed environment so they recovered and reused the media.
That was ten years ago, It can work, with the right people.

Rust... after bare metalling, depending on the humidity it needs to be primed within thirty (30) minutes or rust will start, even before you can see it.
Otherwise, go over it with acetic acid to kill rust in the pores.
Leaving stuff bare too long is one reason why repaints fail after not many years.

Residue... vacuum out the paint booth, paint indoors in still air so there's nothing to disturb the residue, wear a clean coverall, wipe with a tack rag before you start.

Chemical stripping has its issues, especially chemicals lurking in the seams.

Anyway, hope you get it done in the end.

Ivor


tr8todd
Todd Kishbach

(372 posts)

Registered:
12/04/2009 07:42AM

Main British Car:


Re: Dustless blasting
Posted by: tr8todd
Date: February 01, 2020 05:07AM

Car is painted white. Sliding roof will be a nice addition. Picked up several yards of black canvas to recover the roof. Its on the list of Winter projects, but need the wife's help. Getting her motivated to sew has been the limiting factor there. Sand has been a never ending battle. Ran out of warm weather so I still have to go back and paint the black on the rockers and on the rear light panel. Have to paint a green convertible some time after the weather warms up. Ordered a couple of rolls of sand paper for the sander. Have a gallon of striper for the larger areas as well. Will start prepping that car in a couple of months.


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