Joe,
Sorry to hear about your horrible experience with the blaster. That really sucks.
It's my biggest fear with the 57 I just bought. The plan is to strip it complete. The company that will do mine has done many vehicles & I've seen them after he has blasted them and they all look great, plus he has it written into his agreement that if he does any damage he will repair or purchase.
BB

 

Not sure how sand blasting can cause warping.

 

Normally it's caused by the combination of too much pressure and too heavy a grit. It can also be caused by staying in one place to long. It's actually like peening, if you peen or hammer a piece of metal you are compressing that area. On a panel that compression has to go somewhere so it will result in a bulge or if you want you can call it a warp or distortion.

 

Joe, If you don't mind me saying, I think it may be time to step back and think about this for a bit. Is the car really ruined? Or just damaged? What's it going to take to fix it? If you just sell it, and later decide to try again. can you replace it for what you have in this one? Think on it before you decide.

But one question. Why are you wearing welding gloves to hold a straight edge?
Best of luck!

 

I agree - I know its difficult but cool off for a couple of days and then reassess the situation. Get some one that knows about this type of problem to look at it and ask/talk with them about it. What ever your decision good luck.

 

That's the damage everyone is warned about!
He used too coarse a sand and way too much pressure.
I bet it only took him a couple hours to do it.
You really need to go after him for the damages,since he doesn't know what he's doing or just didn't care.
Sorry it happened to your car(and you)!
Mike.:bowtieb:
:gba:

 

It's not heat. It's the peening that warps the metal.

 

If you don't believe blasting generates heat, try blasting at night. You can see the sparks flying of the metal. Not saying there is no peening going on too. but the heat is expanding the metal.

Don't give up on your project yet.

if the damaged areas are localized. it can be repaired.:anim_25:
:gba:

 

I don't care if it's heat or pressure, sandblasting with powerful equipment in the wrong hands can warp like crazy.

 

I own a sand blaster and my freshly blasted parts are not hot. In fact they are not even warm.

 

Yes you're blowing cold air at them.

Regardless Joe has a messed up Hotrod and that's bad.

 

From the pictures, that looks like a case of pure incompetance. What did he blast it with? gravel @ 500 psi?I have done numerous body panels and frames with a sandblaster and have always used the finest grit for sandblasting and no more than 120 psi. Never had a problem with warpage like that but the finish just looks dull not hammered.

 

"I’ve had it dealing with incompetent buffoons and aftermarket parts that don’t fit. I’m going to sell what I have and surely loose my paints. Guess this part of my bucket list will never be completed. "

Joe, there is no doubt you're at your witts end and no one can blame you. But all is not lost and I'd encourage you not to give up on the project.
Even the best builders have set backs and that's how you need to look at this and as a lesson learned, albeit an expensive one from your point of view. The bright side is your body is still in better shape than some of the one's I've seen guys on this forum take on, crazy when almost every piece of sheetmetal needs replacing.

Take some time off, enjoy the holidays with your family and re-engage on the project after the New Year. You have a great build going and I think I can speak for everyone when I say we want to see you finish it. You're doing it right and just need to stay the course, even with all the frustration of incompetent people and parts that don't fit right....have patience with those things out of your control and don't give up hope..or the build. You can finish what you started!

Jim
AKA..Frogman..

 

This is the best advice that you have gotten so far. When you take time to think, you are in better shape on your build than 80% of us when we started our build. :anim_25: :shakehands:

 

This is why I will never give up on the human race. People like you all. Thanks for the encouraging words.

After a bottle of wine with my adorable wife, she (and some of you) have convinced me to not give up.

I have stopped payment on the check and will be hiring a lawyer (he's a friend so it will be free hehe) and request restitution for his incompetence.

Now on to more important matters, how do I fix the issues at hand?

I know how to fix dents but the damaged areas that are warped are unlike any I've fix before. It's more like an ocean of 6' waves on the truck lid ~ ~ ~ ~ ~.

I have a shrinking disc, should I apply heat to the raised areas or center of the warp or us my stud gun dent puller? Any advise would be greatly appreciated.

Thanks again for all the help!

 

It's more like an ocean of 6' waves on the truck lid ~ ~ ~ ~ ~.

Well, At least you can you can replace the truck lid if force to.
http://www.classicchevy.com/catalogsearch/result/?search_year=ALL&q=trunk+lid&x=33&y=5

:anim_25:

 

Stay the Course!

Joe,
Despite this setback, don't give up! I'm pretty sure that everyone here has suffered through a period during their restoration when they wanted to throw in the towel (myself included). If you think you feel bummed out now, just wait until next spring at the first car show when you see a 55 that catches your eye and you say to yourself, "that's what I wanted my car to look like, if I still had it...". I agree with the suggestion to take a little time off, enjoy the Holidays, re-charge your batteries, and when you're ready, give it ****!! That's a decision you won't regret.

Best Wishes,
John

 

could someone kindly post "specs" on how much PSI to use what dia bore of the blasting gun and the best Media to blast with?

 

Soda or Plastic is best! Never sand blast panels it creates too much surface profile that will have to be filled by primer and sanded off.


Joe:shakehands:

 

It takes a little longer, but I like to use a small blaster ( no bigger than a 100 lb. pot) and no more than 80 or 90 psi at the pressure guage on the blaster.... whatever is just enough to take the paint off and clean the metal up. It takes more sand that way, but sand is much cheaper than high build primer or new sheetmetal. It's dummies like that that give sandblasting a bad rap.

 

Now on to more important matters, how do I fix the issues at hand?

I know how to fix dents but the damaged areas that are warped are unlike any I've fix before. It's more like an ocean of 6' waves on the truck lid ~ ~ ~ ~ ~.

I have a shrinking disc, should I apply heat to the raised areas or center of the warp or us my stud gun dent puller? Any advise would be greatly appreciated.

Thanks again for all the help!

Doc why don`t you pose this question in the paint and body work or the metal fabrication forum ?
Terry

 

good to hear your not giving up on it. if your getting a lawyer (free is great), then you might have to have a pro look at it. you will need his opinion to prove anything(damages). :anim_25:

 

I have to agree with some of the posts, take a step back figure out what needs to be done to fix the problems.

I built my own rig, about $400. I can normally blast for 15 to 20 min. Arm gives out after that. Take a break let pessure build back start again. Spent many hours under my 57. No damage to panels. Did not blast body panels though. just the heavy metal, floor pans etc. It's there any time I want to clean something up. It's also a dirty job, process should be on T.V.

 

Doc, sorry to hear about your bad experience. We've warned guys here for years about sandblasting. As mentioned, this has nothing to do with heat...it's the peening of the metal that warps it. I would never sandblast any flat panels regardless of pressure or sand grain size.

I thought you had the whole car stripped except the edges of the panels and window openings. That's how I did mine too, and then I blasted the rest with silica sand that looks like salt. It's "medium" sand, but I think it's pretty fine. It doesn't seem to warp anything and I use high pressure to cut faster.

Too bad you didn't stop him when he started blasting the flat panels. He obviously didn't know what he was doing, and i hope you get it straightened out.

I have a 56 sedan that I am afraid may be in similar condition to your car. I bought it in primer, and it looks like it was sandblasted. I haven't assessed how bad it is yet, and won't start on it for a while. Luckily I have a very nice spare hood and trunk lid if needed.

 

Read about you troubles and sorry to hear what happened. You had someone that didn't have a clue about cars. Some ask about nozzle size and abrasive sizes so here goes.

Nozzles Use a No. 3 or 4 which have a 3/16'' and 1/4'' orifice.
CFM no more than 120 PSI at the machine can be less just takes longer this will give you somwhere around 90 to 95 at nozzle depeding on hose size and length.
Media There are a lot of different types that can be used
Garnet 80 to 150 mesh
Aluminum Oxide 180 to 220 mesh used on turbine blades
Glass Beads 140 to 230
Walnut Hulls
Blasting can be carried out on cars you just need to find someone with knowledge working on cars.
Terry

 

A while back I posted what I had done to build the rig I have. I used Harbor frt. blaster. Thay don't sell the blaster I bought. The one I have has a dished top. So put a screen over the top and filter used blast media. I use Tractor supply black diamond fine. Takes awhile to clean but no damage.

 

Chevynut,

A while back you answered another members question about sandblasting and recommended he not do it. Yours and several other members great advice was the main reason I used paint stripper on mine and not sandblast.

I told the fool I only wanted him to do where I could not reach like in the corners, around the window frames etc., and "please" do not hit any panels. That's what I get, leaving for lunch and not watching him the whole time. Live and learn.


chevman57, good idea. Thanks!

 

With my HF pressure blaster, I'm not sure I could ruin a panel if I tried. Not on the 19 gauge tri-five metal anyway.

It did do a heck of a good job with rust though.

 

Prolonged exposure to pressurized sand can easily warp metal. This is because as the sand particles strike the metal, they create friction, which in turn creates heat. As the metal heats up, it expands, typically outward. Metal warping is almost impossible to detect while blasting, unless the metal produces a loud "pop" sound. For this reason, the warped metal is not discovered until the sandblasting process is complete. As a result, although the rust has been removed, a new problem now exists. To avoid warping the underlying metal while sandblasting, avoid sandblasting the same portion of metal for more than a couple of seconds and allow that portion a few seconds to cool before blasting again

Read more: Tips for Removing Rust by Sandblasting | eHow.com http://www.ehow.com/way_5340734_tips-removing-rust-sandblasting.html#ixzz1hEONGTUq

 

Sorry but whoever wrote that article on the ehow website is FOS. As already stated several times, warpage from sandblasting has nothing to do with heating of the panel. You could spray ice water on the back side of the panel and it would still warp. It's caused by "peening" of the metal by the sand particles, which stresses one side of the panel. This stress causes the panel to buckle.

If you don't believe it, next time you sandblast put one hand on the backside of the panel. It will not heat up. It takes quite a bit of heat from a torch to warp a panel.

 

That project is by no way too far gone, you still have a repaireable project :anim_25: