Soda Blasting vs. Sand or Glass Blasting? What is your Experience?

[KYBlueOval]

After the first of the year, I'm going to have my Ranchero body blasted. The local firm that I've decided on using can and will use Soda, Sand, Glass, Walnuts etc.,......whatever it takes to get it clean.My concern is the horror stories I've read about Soda Blasting causing paint to bubble. When this occurs it becomes a swearing contest between the blaster and the painter, both saying the other is the cause of the bubble problem.I should add, that I've stripped the flat surfaces on the doors, quarters, tailgate and roof with a DA, but have not done the irregular shaped areas......door jams, A pillars, window frames etc..
So my question to the Forum is this...........what is your first hand experience with Soda Blasting? Good? Bad? What measures must be taken to insure a successful outcome?  Or should I just stay away from it altogether?
Merry Christmas and Thank you for your comments.
John

[JimNolan]

John,
   I just got a 66 Fairlane convertible sand blasted and repainted. A Mexican that has a shop in Goshen, Indiana had it done before they painted my car. I jumped up and down about using sand because the car was rust free an I didn't want the panels warped. The Mexican said that happens when the people doing the blasting don't know what they're doing. They sand blasted the bottom of the car, engine bay and outside of the car. When they finished painting it, it was straight as an arrow. Apparently they had some reason for not sand blasting the interior. I'd like to tell you more but the Mexican couldn't speak English well enough to hold a conversation except through an interpreter. I'll never have a car painted by someone I can't speak to again. But, he did a pretty good job.

[Wirenut]

I've media blasted with sand a couple of my cars and frames and one was eight years ago the other 15 and no paint adhesion or warping issues. I do agree, if the blaster does not know what they're doing they can ruin a car. It is a must to literally blow out, vacuum, and clean multiple times to remove any particulates in nooks and crannies. I also recommend a metal wash that is a good step. I wiped the entire car down with it and clean it off in sections prior to priming and have been pleased with the final process. I would recommend looking at some of the blasters work prior to commitment.

[lalessi1]

I had my hood stripped and repainted on both sides. When I picked it up it looked good and I found out the painter had sand blasted it. He said low pressure and low angles were required to prevent warping. As the paint has aged the hood shows a lot of waviness that I think resulted from the sand blasting. It is very subtle and I am not sure whether it was originally there before but I would not have my car sand blasted as I am not comfortable with it now. Perhaps walnut husks or dustless blasting?

[gasman826]

Cleaning out the media is a pain.  Just when you think you have it clean, roll the body over, rattle it a bit and more sand will sprinkle out onto the floor.  I used seven inch black scotch brite pads to strip paint from the flat surfaces and contracted out to have the crevices and floors blasted.  Much faster, cheaper and less dusty than DA. 

In my blast cabinet, I like black, coal chips.  Cheap, durable, little dust, and aggressive.

[RICH MUISE]

John...you've already probably figured out the more you read on this the more confusing it gets. Everybody has different opinions...here's mine, lol.
First, media blasting of any type does not prep a surface for painting. The guy who complained that soda caused the paint to not adhere??? 99% sure he didn't spend any time getting the car ready.
I think all the stuff you read about SANDblasting warping panels because of heat is pure BS. The panels may warp but not because of heat generated....I've never felt a panel get hot from it. IMHO It more than likely is caused by very high pressure at the nozzle of a commercial blaster and/or stress relieving of the surface. Lynn's problem with the hood having waves..?? I'd need to know more. ALL '57 panels have waves from the factory. Most that have a car repainted spend many many hours eliminating those waves/ripples/distortions with all that blocksanding high build primer that we do.
Gary was pretty much spot on about several things imo. The sand will never be totally gone from the car. plan on hours and hours with air blow guns to get the majority out, your frame and crossmembers will fill up as well as the pillars, and just about any crevice. And it will be still coming out of some areas 5 years from now. With that said, I think sandblasting gives the best tooth for surface prep.
Soda blasting is more gentle on surfaces and is water soluble, so the stuff can be washed out with water...but who wants to soak their bare car down with water ?? here's the biggie, imo:..Soda blasting will NOT remove rust. It's only good for removing paint and stuff on the metal, not actually removing corrosion from in the metal.
Also what gary said about stripping easily reached exterior expanses/areas with a rotary stripper. It's fast, and minimizes any potential warpage.
Be prepared to do whatever you're going to do for temporary surface protection when the car gets back from the stripper. You don't want it to be sitting long without some protection. I'd do a Zinc chromate bath here in Texas as our humidity is low and the ZC will protect it adequately for years indoors. High humity areas will rust flash overnight.

[terry_208]

I too have been worried about cleaning the panels of my car.  I've thought about having it dipped but I'm afraid that like blasting, the doubled and triple walled areas won't be cleaned. Some of the smaller items, hood, trunk, and doors, could be separated as DJ and others have done but I can't do that to  the main body assembly.

Yes, definitely the more I read the more confused I get!   

[Limey57]

Now my opinion based on experiences. 

Many years ago (okay, 30 years ago) I worked in the school holidays for my uncle who had a truck body building business, I worked in the spray-shop and most of my jobs involved shot (and sand) blasting truck and trailer chassis.  Occasionally we'd get someone ask to have a car body blasted and the trick was 9as others have said) to keep the angle of the nozzle at a shallow angle to the panel, turn down the pressure and stand back a bit.  Even then we always stayed clear of large flat panels, just blasting their edges and letting the owner strip the flat panels back with a DA sander.

Yes, the media gets EVERYWHERE.  When I have a body or chassis blasted I plug every hole I can find with scraps of wood, shaving it down to a taper and hammering it in place, leaving an inch sticking out so it can be pulled out.  All tapped holes are plugged with a bolt.  In my opinion nothing beats blasting to remove rust.

As Rich said, soda blasting is a gentle blasting process that can be used to strip paint layer by layer, but it will not remove rust.  Be aware that blasting with sand is hazardous due to the silica dust (it's actually illegal over here to use sand), if used, wearing a filter mask is a good idea.  I have a small hand held blaster for small rust spots, it works well but takes a while.

Acid dipping.  Don't do it, see my build thread for what the acid does when it gets into the welded seams..............

For me it's sand/shot blasting every time, yes it makes a mess, but it removes all rust.  Steer clear of large flat panels (use a DA sander) and a small hand held blaster for any rust spots on those panels.

[djfordmanjack]

Lots of facts here and many good personal experiences as well.
I'd say each of the methods has their own right at certain circumstances, parts design and depending from the condition of the parts. Since it is easily available to you I would use soda blasting for all the corners, interiors, door openings aso, would carefully sand the flat areas ( take care, a DA develops more heat than what you'd care for in a second, when used with an old worn pad. You'll have a panel warped in seconds) and after the paint has been removed have the rusted sections media/sand blasted and/or chemically rust stripped. If that sounds like a whole lot of work and getting expensive- yes it sure is. but that's the only good foundation when doing a ground up resto, like Gary 1&2 and Rich said, proper paint adhesion depends on thorough wipe down with metal and silicone cleaner. Every little part of that (car) body has to be touched several to dozens of times until it will be ready for final paint. That's the reason why quality paint jobs are so expensive.
each method probably could be made good use of, if the working person knows and cares about what he's doing.
So John and Terry you either have to study all those things a lot more so you can tell the person working what exactly you want them to do or you got to find somebody or a shop and their professional employees that you fully trust in that they make the decision what's best for the car. I would not recommend handing out the car to just SOMEBODY that is close and he will blast and primer it in a day or so.

I think all the stuff you read about SANDblasting warping panels because of heat is pure BS. The panels may warp but not because of heat generated....

I am sorry to say so , Rich, but NOT SO !
try holding a bit of steel object in the blasting cabinet and give it a good shot for 5 seconds or even aim right at the thick rubber glove, that protects your other hand, and you will feel the heat immediately. I am doing shrinking work with  torch, electric stick and shrinking (friction) disc and can tell you that 250-300 degrees are enough to pull a flat crowned panel out of shape or back to shape again. the friction of the blasting media will heat up the surface enough so that it'll shrink out of shape when it cools back off.

There is something else I want to mention and I donT' know if the tools are available in the US, but over here we can sand blast with water. Now that sounds stupid I know. you take an industrial high pressure water cleaner, with a special device sucking sand from a huge barrel or else and then you wail away on the object to be cleaned. no heat because the water cools it down so much while shooting. and no dust. but a lot of messy and cold and wet other problems. not something that you can do in a Michigan or Canada winter
you have to spray the body with special primer immediately and the steel will not rust. How good is that, you ask ?
I personally know a guy who uses exactly that for stripping $500k 1960s Maseratis and Mercedes.

I think a guy in the US who strips with soda will also be able to strip the rusted areas exactly that way afterwards.
Most probably clean results will only be achieved after several steps.

[Ray]

Anybody looked at laser stripping? I've seen some pretty impressive demonstrations recently.

[Jeff Norwell]

Sandblasting will warp panels..... and is usually done by an individual who has little experience.Up around these parts. most car guys i know use an experienced media blaster.. some use glass... some use walnut ground shells... some use silica sand.... You get what you pay for I guess...... I like glass or walnut media blasting.

[KYBlueOval]

Thanks to all that have replied. Exactly what I was hoping to get.Thanks!
With a DA, I stripped ALL of the FLAT panels to bare metal, Doors,Tailgate (it's a Ranchero ), Quarters, outside and the flat panels in the bed area, Roof, Flat panel below the rear window as well as the other side behind the seat. I did this to eliminate the possibility of these panels being warped. The body is off the frame and will be on a rotisserie when blasted. The frame was done months ago. 
What is remaining is what you all have described....the irregular shaped areas.....door jams, windshield frame, firewall, bottom,interior etc..
What I'm undecided on is the use of Soda. What I've learned about soda blasting is that it can cause paint issues later, if not done correctly.But what exactly is the right procedure when using Soda to insure there are no paint issues caused by the soda?
Merry Christmas and THANKS!
John

[RICH MUISE]

As I mentioned in my first reply, if I were doing it, I'd acid etch/zinc chromate all surfaces. I work the stuff wet with skotchbrite for 20-30 minutes until the gray coating starts to appear, then hose it off. The stuff works quicker in warmer weather. If that doesn't get rid of any soda residue, I don't know what would. I leave the coating on the metal to keep rust from forming until paint time. There is a procedure for getting the ZC treated parts/panels ready for paint that is critical for proper paint adhesion. If you decide to go that route, let me know and I'll do a post on that.
The stuff I use, btw is por-15 Metal Ready. works great, and is envoiroment safe. You can do it on your lawn.

John, It sounds to me like you've approached what your doing correctly.
DJ...I guess we'll have to agree to disagree on the heat thing. If you stress relieve a piece of sheetmetal on one side only, it will warp. When I was in manufacturing years ago, in addition to a very large machine shop we had, we also ran a large precision sheetmetal shop. Occasionally bluprints would call for a panel to be grained prior to finishing. If we only ran them thru the graining machine (very wide water cooled belt sander) on one side, the panels would warp and need to be straightened. When we could, we'd grain both side and they went back flat.
Also, I can pretty much guarantee a car sitting out in the Texas sun is going to get much hotter than proper sandblasting.....it's give you blisters on your skin time in very short order. Most of the good salvage yards in Arizona are subjected to incredible heat throughout the summers.....for 50 or 60 years. So, I'm not saying sandblasting won't warp panels, I just have a different idea on why it may warp.

[lalessi1]

There is something else I want to mention and I donT' know if the tools are available in the US, but over here we can sand blast with water. Now that sounds stupid I know. you take an industrial high pressure water cleaner, with a special device sucking sand from a huge barrel or else and then you wail away on the object to be cleaned. no heat because the water cools it down so much while shooting. and no dust. but a lot of messy and cold and wet other problems. not something that you can do in a Michigan or Canada winter

"Dustless Blasting" is available here. It is advertised on the "Velocity" channel and there are classified ads for a contractor.

[terry_208]

I had the fenders media blasted without noticeable distortion.  I realize they are high crown areas and there not as susceptible to warpage as the low crown areas.  I need to clean the complete outside and inside of the main body as the floors need replaced and also the lower rear portions of the quarters.  I don't know which way I'll go to remove the rust.  I just know it has to be removed!