soda blasting

[Joe T.]

my body shop just picked up my 66 roadster from a soda blaster, they said the car may be ruined, the soda blasting took the paint and primer off and apparently left a very pitted,uneven, and ragged surface, he said there are deep abrasions and in some areas it looks like a spoon was used to gauge out chunks of fiberglass, not to mention that the entire inside of the car is covered in baking soda including the air vents, behind the dash, the carpets , the nooks and crannies, even the face of the radio and instruments are covered, he's upset and i'm upset, i can clean up baking soda but i'm worried about getting the car ready for paint, has anybody had a car soda blasted? what was the surface like after? what did you put on after the blasting i.e, gelcoat etc, any input at this point would be greatly appreciated, signed, upset joe in massachusetts

[Clare Carpenter]

Re: soda blasting

Wow! That doesn't sound like soda blasting. Something was done wrong, either with the selection of the soda formulation, (there are more than a dozen types of soda media, each designed for a differant task) or perhaps in the application, (too close, or at too much air pressure, etc). It sounds like your car was together with the interior intact and on the frame. If media blasting were to be used in this scenario, whether walnut shells, plastic or soda, all seams, holes, vent openings and windows should be taped off and care taken when directing the media. That would keep it out of the interior of the car. Common sense should dictate not to try and media strip a door jam on an assembled car. In a body off situation soda dissolves in water and can be rinsed off. Still car should be take to not get it where you don't want it. Media goes everywhere!

Soda is designed to fracture on impact. It is a "one-pass" media. It was originally developed for cleaning and restoring the delicate copper skin of The Statue of Liberty. It is delivered under low pressure but high volocity. It can be very gentle, in fact, it is possible to clean the paint off a soda can without damaging the substrate with the right media. With a special formulation it can also be used to blast rusted steel to a white metal finish with a 1.5-4 mil profile.

As you know, there is a lot of difference between rusty steel and 40 year old fiberglass. That said, I know of cases where someone has used sandblasting to strip a Corvette with good results, as crazy as that seems. In fact, there is a restoration shop in TN or KY that advertises that fact on their website and shows the process being done. I cringed when I saw that, because I thought of the do-it-yourselfers that might try it and would screw up their cars.

Why did you choose to media blast the car? Did the bodyshop play a role? How long has the stripper been in business under the same owner/operator? How long have they been working with soda? They certainly should have tested a small panel before starting. In lieu of that, they most certainly should have stopped when they saw damage occuring. I would think they bear responsibility for the damage and would inquire as to their liability policy. Good luck, I hope the damage can be fixed with good results.

Here is a couple of links that you might find interesting and helpful.

This car was stripped with soda and had excellant results. http://www.richscorvettes.com/Web_Si...30/Page_3.html

This is the Armex company website. http://www.armex.com Lots of good info on the process and types of media. Their composite formula is deisigned for fiberglass and graphite epoxy substrates. There is a technical data sheet available on the website.

[Tracy C.]

Re: soda blasting

Ouch Joe,

If there is sufficent thickness remaining on the panels, I think you could resurface them with a half and half mixture of bondo and polyester resin.

I know it sounds a little far out but these materials are completely compatible as they are both polyester based. I've mixed these before with excellant results.

Work only about a 2 foot square area at a time. First mix the resin with the correct amount of hardner, then mix the bondo with the correct amount of hardner, then mix together to the consistancy of soft margarine.

Spread this mixture over the surface with a plastic spreader. Really mash down into the pitted surface and try to leave a minimal amount to block sand off later. This mixture will spread to a thin layer without the typical "lifting and peeling" that normally occurs with straight bondo.

Block sand the surface when it cures and use some "fast build" urethane primer when you think the panel looks pretty good. You have more "gun time" with urethane vs. sprayable polyester gelcoat and the resultant finish coat is less prone to wavyness due to shrinkage "after" you block sand later on.

This job is not for the typical "get it done today" body man. It will take some serious time and patience to bring the surface back.

I'd also recommend a healthy coat of epoxy primer (DP50) before the top coat goes on. This might prevent screwing the surface up if the paint is chemically stripped next time.

good luck,
tc

[Patrick H.]

Re: soda blasting

Corvette Fever ran a series of articles on the "Restoration Celebration" 1953 Corvette that Carlisle Productions restored. The outfit in Tarpon Springs, FL that did the car (see link below) used a certain type of gelcoat from the boat industry to refinish the car. A friend of mine used that on his 60 after we read the series, and it turned out quite well.

Generally I don't recommend gelcoat, but in your case I'd recommend calling them and getting more information.

Patrick




Classic Corvettes

[Warren F.]

Re: soda blasting

Joe:

Like Clare said soda blasting can work well, when used PROPERLY! However, I also had a Corvette soda blasted in 1988, and the results were DISASTEROUS. The complete exterior fiberglass was cratered and I had to use Featherfill over the entire body to bring it back to acceptable condition before priming for paint, I would never recommend this procedure.

I too was shown that the lettering on a cigarette package could be removed with this process, that it could be a gentle method of paint removal. The problem I suspect was that the paint material was tough and that the pressure needed for removal was much greater than our fiberglass surfaces might endure.

Sorry you have to go thru this experience of repair as well, good luck.

[Clare Carpenter]

Re: soda blasting

Joe, The material Patrick referred to is called Awlgrip. The '53 body was really in rough shape and presented several challenges. Here is the link on the restoration: http://www.ccrestore.com/dev/1953/index.cfm?action=home
I have seen this material used to "skin" a Ferrari prior to painting with spectacular results. This particular Awlgrip product was sprayed on like gelcoat and was white in color.

[Clare Carpenter]

Warren, Are you sure it was soda blasting?

I don't think soda blasting was around in 1988, at least I had never heard of it until within the last few years. In fact, I first heard about media blasting for automotive paint removal in the late 1980's. Plastic media (same material used in plastic table wear) was the latest, greatest, new thing back then. Plastic can definately pock mark fiberglass but again it's all in the hands of the operator. Put a minimum wage lackey on the end of the hose and you are going to have problems.

[Warren F.]

Re: Warren, Are you sure it was soda blasting?

Clare:

Yes, I'm sure. It was the latest, greatest new fangle system to use. My restoration person and I attended a preview of this new modern system at a location in California. It was demonstrated to us using a fiberglass hood from a C2 generation Corvette. What we didn't realize at the time, was that when using this system it took awhile to do a small area being careful, using a much lower pressure, the results were impressive! Both myself and my restoration person walked away thinking this was the cats meow, for a stripping system. However when we dropped off my '70 coupe, it had been repainted since factory, and apparently when we arrived to pick up the car to take home, the shop explained to us that it was very difficult to remove the paint layers, so they had to use a much higher pressure and stay on the body area much more. The results were a very cratered surface, which my body man was horrified to see. We ended up spending an enormous amount of time to correct this shops results!

[Clare Carpenter]

It still comes back to the operator.

Warren, in your example was the shop that did the stripping the same as those who put on the preview? You mentioned it worked great at a lower pressure when the job wasn't rushed.

Joe hasn't piped back in here with any more info but I would put the blame on his stripper. They should have a liability policy to cover this type of screw up. If the body shop "farmed out" this job then their liability coverage should pony up. Joe shouldn't have too eat the cost of repair.

Might be a good lesson here for others considering a dry stripping technique, make sure the shop has a liability policy in good standing to cover this type of situation. Just asking for proof of insurance would probably make them more careful and cause them not too rush the job. It boogles my mind though that they wouldn't stop or change technique once they saw damage occuring. Probably the first Corvette they stripped and hopefully the last.

[Warren F.]

Re: It still comes back to the operator.

Clare:

Yes, the shop was the same as the demonstration set-up at a big swap meet. There excuse for the surface disaster was that the material was tougher to remove at the lower setting, and taking way to long, so they increased the pressure to remove it more completely and quicker. The next 'vette I had restored was NOT dry blasted that way, good old fashion sanding.

[Mike M.]

Mine Was Soda Blasted

I had mine soda blasted and it came out great. The people doing the body liked it so much that they send there vettes to them now. They have been doing boats for years so they had experience with fiberglass.

[Joe T.]

Re: Mine Was Soda Blasted

i haven't chimed in yet because i've been too busy throwing up, the body shop claims the soda blaster didn't know what he was doing and has cinfirmed this with other body shop owners, the soda blaster and one reputable vette shop say that that's the way soda blasting come's out, i'm sick about this, i wouldn't recomend soda blasting unless you're going to be there to watch and make sure they stop if they're ruining the fiberglass, i'm now trying to figure out what to do, keep in tuch, joe

[Clare Carpenter]

Re: Mine Was Soda Blasted

Joe, I don't believe you should have to eat the extra costs of repairing your panels to get ready for paint. Keep us posted on what happens but like I said in my earlier posts I'd definately check with the stripper on their insurance policy. If they don't have one or won't reveal the company name to you, take them to small claims court at a minimum. Some states have up to a 5k ceiling. If the body shop was responsible for farming out the job then they also bare some responsibility for this screw up. Good luck to you.

[Craig S.]

Re: Mine Was Soda Blasted

Joe - best of luck with your problem. I tried the plastic media route on a set of headlight shells once back about 10 years ago and was very unhappy. Very pocked up, and I had the same sales pitch about how gentle it was. I was thinking this soda route was better, but it sounds like the same issues can occur. Bottom line, if done correctly and with skill, it all works. If done in a hurry due to "business" needs, it is a disaster. One of the reasons I hand stripped my own cars.......good luck, we look to see how you make out. Craig