Is media blasting too harsh on an old body?

[Tom F.]

What do folks think of media blasting like this? http://www.thesamba.com/vw/classifie...php?id=1224549

[Greg D.]

?? I had a 65 Karmann ghia media blasted once, and it yielded great results. As long as the operator is not ham fisted and warps all the panels, I don't see the problem... I did vacuum media from the car for years afterwards, but bodywise it was a great way to see what you got.

[hoffman912]

I dont see why it would be. it cleans everything up and quickly identifies anything that has been blessed by the pope (holy). if its weak it needs replaced.

now one thing to keep in mind is that it should be done by a pro. i dont know the exact specs, but if you go in either too shallow or too sharp, you will either a) not remove any material or as much), or b) risk burning through metal, or warping it by the heat at least.

still.. done properly i dont see any issues with doing it.


and yes you probably will be finding media in places for years. i think John T said he still finds walnut shells in places in his.

[LongRanger]

That link didn't work for me, but . . .

I guess it depends on what's getting stripped.

I've had wheels stripped, using walnut shells. These were Porsche GT wheels (356, steel + alu) and I was being super careful --- the wheels weren't damaged or delicate but they took me, like, 5 years to find, and pricey to boot --- so no 'oopsies' allowed. I talked to the Blaster Guy, who said that very little heat would be generated and absolutely every molecule of paint and corrosion would come off. No sh!t. Three of the wheels looked so good naked, I was tempted to just leave them as is.

Anyway, I liked walnut shells because . . . 1) did a great job (on wheels, at least) . . . 2) it's a light-weight media that generates very little heat on the part getting blasted (so no distortion/warping), and . . . 3) the stuff's organic --- nothing toxic or caustic (unless you're allergic to walnuts).

I've heard stories about sand- and glass-bead blasting --- warping/removal of parent material, high heat making things brittle, having a ton of media packed into all the little nooks and crannies, that then leaks out, like, forever . . . but I've never had anything rusty/krusty/nasty enough to need that kind of stripping, so . . .

What I have used are chemical strippers --- uber-nasty haz-mat suit stuff . . . gloves, eye-protection, plenty of ventilation, etc. But nothing beats it. Turns paint/bondo/flesh into soft sheets of stuff I can pull off with a putty knife. I stripped a whole car down, by myself, in one morning. And I was an idiot, too --- had absolutely no idea what I was doing (very first car project --- kids!) --- but, even then, I knew enough to keep the stuff outta any seams or hard-to-reach places. 'Cause the problem is that the chemical stuff, like media, if it gets in somewhere out-of-the-way, will leak out, and, unlike sand/glass/walnut shells . . . it'll eat any paint/bondo/flesh it comes in contact with.

Honestly? In my opinion, the best way to take stuff off? Time-consuming, labor-intensive, and a total PiTA . . . do it yourself --- by hand. A grinder, a compressor, some dust-protection, and a sh!t load of sanding pads. All it takes is time.

[Bullethead]

Media blasting is fine with the right media and technique, but as noted you'll be vacuuming the unintended consequence for years.

I agree with Rick: chemical strippers work the fastest and best, just neutralize after an alkalai rinse and treat with phosphoric acid immediately. The nasty old standby "aircraft stripper" formulations have changed... which is probably a good thing health wise, but don't work as well as they used to. Several water based systems that rely on ecapsulation with a lift sheet work very well but are kinda pricy and from experience, take forever because they're cold... heat helps remove paint.

The ultimate is two-tank immersion of the entire car from companies like Redi-Strip, if you're lucky enough to have one nearby.
First tank is a hot caustic solvent that will loosen paint and grime, after which a pressure wash removes everything.
The second tank is an electrolytic alkaline bath that will leave metal shiny as new... even the Swiss cheese parts.

[C.Plavan]

Sodablasting would be better for removing paint. Then it just rinses away with water.
I sandblasted the interior of my race car prior to paint. It looked like I partied at a beach each time I ran the car during a race. Sand came out for about a year. It really looked like a Corona Beer commercial.

[chris_seven]

Media blasting can produce high levels of residual stress and warp panels if not carried out with care and I have seen some dreadful results,

The only issue with soda is that it won't remove any corrosion so you end up with rust still visible.

We have used a controlled pyrolysis oven for some years now. The shell is heated to about 350 degC and all the paint and sealant turns to ash but doesn't burn so there is no distortion.

A light glass bead blast then cleans up the surface without to much effort and removes the rust quickly and efficiently.

Cleaning the fresh metal surface with a Phosphoric/Citric Acid cleaner then leaves a bright substrate which is relatively passive and ready for repair and etch priming.

[hoffman912]

What I have used are chemical strippers --- uber-nasty haz-mat suit stuff . . . gloves, eye-protection, plenty of ventilation, etc. But nothing beats it. Turns paint/bondo/flesh into soft sheets of stuff I can pull off with a putty knife. I stripped a whole car down, by myself, in one morning. And I was an idiot, too --- had absolutely no idea what I was doing (very first car project --- kids!) --- but, even then, I knew enough to keep the stuff outta any seams or hard-to-reach places. 'Cause the problem is that the chemical stuff, like media, if it gets in somewhere out-of-the-way, will leak out, and, unlike sand/glass/walnut shells . . . it'll eat any paint/bondo/flesh it comes in contact with.

I used chemical stuff for a number of small projects a few years ago. after it started eating through rubber gloves ad getting on my hands though i was screwed.. had nasty chemical burns on my hands for over a month. they were blistering like no tomorrow then the skin got really tight like i just had face job (think joan rivers).. could barely bend fingers for a week at one point..

never again unless i have to.

[66S]

I use chemical stripper then go to abrasives. I put plastic food wrap over the stripper to extend the time it works and go deeper into paint layers.

[210bhp]

Chris

I am in the UK and would be very grateful if you could share the contact details for the three part process you describe above. Is it in-house or an outside source? What you describe seems a very sensible process for a complete shell. You can pm if you feel happier.
Many thanks.

Regards
Mike