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straightening sheetmetal

Discussion in 'The Hokey Ass Message Board' started by coody, Mar 30, 2009.

  1. coody
    Joined: Mar 8, 2008
    Posts: 116


    had my model a sedan sandblasted and it didnot come back straight.What is a good way to straighten this out with the min of filler.Any info would be great.
  2. oilslinger53
    Joined: Apr 17, 2007
    Posts: 2,473

    from covina CA

    your gonna have to learn to shrink/ stretch metal
  3. rodknocker
    Joined: Jan 31, 2006
    Posts: 2,267


    John Kelly on here sells shrinking discs, and dvds on how to use them properly.
  4. hotsilver
    Joined: Feb 19, 2008
    Posts: 113

    from Florida

    How much metal working knowledge do you have?
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  5. pasadenahotrod
    Joined: Feb 13, 2007
    Posts: 11,776

    from Texas

    You sure it was straight before it went to the blaster?
    They hit it direct with too much pressure rather than at an angle but soft.
    It should have been free unless there was an illegal under the hood. If the blaster is illegal then pick him up one day on the street corner and take him out in the back forty and show him the Bosses Hole. After emptying and refilling it about 50 times he should understand how to correctly blast sheetmetal.
  6. coody
    Joined: Mar 8, 2008
    Posts: 116


    am in pasadena too lamar swindall in baytown didi it.he has bodies laying around his yard so i thought he knew what he was doing.this was a barn find sedan and been working on it for awhile.had it out at san jac body shop it was all straight but now its a lot of work to do now.chassis is done and just started on the body.
  7. coody
    Joined: Mar 8, 2008
    Posts: 116


    I have some experience in body work.The shrinking disc will be new to me.The torch would be much harder.might buy into the disc and dvd and learn that way.Even thou i got it back all primed and one color i got empty feeling in my gut after looking at the way it came out.I made my floor boards and layed them in there and trans tunnel so that took my mind off the waves!!
  8. Hot Rods Ta Hell
    Joined: Apr 20, 2008
    Posts: 3,870

    Hot Rods Ta Hell

    If it was straight when you brought it to the sandbalster and wavy when you picked it up, he didn't know what the hell he was doing. If you paid for his services, Take it back to him and have him straighten it!
  9. coody
    Joined: Mar 8, 2008
    Posts: 116


    No telling what i would get back.Maybe this is a $300.00 lesson,Down here there isnt very many places that i know that sand blast cars.I am going to call today and do a little venting
  10. Rex Schimmer
    Joined: Nov 17, 2006
    Posts: 743

    Rex Schimmer
    from Fulton, CA

    Basic rule: Never sand blast a body! This is why walnut shell blasting, plastic media blasting etc were invented. Standard sand blasting is way to harsh on a car body the media actually distorts the panels by causing uneven compression stresses in the metal itself and it then distorts.

    You will be a pro with a shrinking disc when your done.

  11. carbuilder
    Joined: Nov 21, 2006
    Posts: 982


    What kind of media would you use on a aluminum body.
  12. bill wallace
    Joined: Oct 26, 2006
    Posts: 104

    bill wallace

    For blasting alum. soda-blasting is the best method. Somewhat expensive but does a great job & is used almost exclusively in aviation.
  13. kopperkart
    Joined: Aug 31, 2008
    Posts: 468

    from Wisconsin

    Blast the blaster. You will feel better.
  14. 49ratfink
    Joined: Feb 8, 2004
    Posts: 17,327

    from California

    I worked on a 52 chevy that the owner sandblasted at his work. problem was his work was a place that made pre cast walls out of cement, and sandblasted their walls with this super duty blaster. this is what he used on the car. warped the hell out of both doors to the point they were junk.

    not only does improper blasting warp the metal, it also work hardens it making it more difficult to get back into shape.
  15. pasadenahotrod
    Joined: Feb 13, 2007
    Posts: 11,776

    from Texas

    We have had a lot of blasting done at a ship service yard over in La Porte TX.
    I'll have to dig out their card and hope they are still in business. They were very reasonable, did excellent work, and timely too.

    Didn't find the card but looked it up in the yellow pages.
    A&L Industrial Services
    1728 N Hwy 146
    La Porte TX
    I believe the man to talk to is Rudy(?).
    He's very friendly and listens to what you want.
    They do big nasty chunk sand(don't do this) and sugarsand(which is what you want).
    Last edited: Mar 31, 2009
  16. MeteorMan
    Joined: Dec 5, 2008
    Posts: 373


    I hate to hear of your bad experience, but sand is bad on sheetmetal. Unless it's done correctly as pasadenahotrod said. There is a right way to do it, but I just wouldn't trust it, I've heard too many horror stories.
    Soda or other media is the way to go, if you can afford it. I've seen where they charge upwards of $1,000 to $1,500 to media blast a car and then you still have to epoxy prime (depend on shop).

    I know it doesn't help you now and I'm not affiliated with any of these shops and haven't had them work on any of my stuff, but recently discovered them after a conversation with my bro-in-law.

    These guys are in Houston (SBW near 288).

    Mo' Muscle up in Conroe does 'state of the art' media blasting

    Here's another shop in Arlington in case anybody needs it.
    I'm sure there's more, just have to Google it.
  17. mecutem
    Joined: Oct 6, 2002
    Posts: 582


    As said already warpage is ruined metal. Only a few sandblaster technicians can do sheetmetal and not damage the panels. You may want to consider putting a coat of grey primer over everything and sell to someone more ambitious and less fussy than you. Then find a better body. Seriously though you will likely never be happy with the amount of work and filler needed to make it look good after being warped out of shape. Basicly all the larger area panels are now too big for spaces. I threw away a challenger shaker hood a few years ago because the sandblast guy was busy and let a ignorant fella try do some parts that day. Steve
  18. model-a-fan
    Joined: Oct 4, 2008
    Posts: 842

    from Kentucky

    The '29 I'm working on was partially blasted by the PO. I was concerned about warpage but after working on it a couple of hours yesterday, I'm glad to say I haven't found any suprises. (Just alot of sand):). Like everyone's already said, it's usually the user and not the tool that gives you poor results.

    Attached Files:

  19. coody
    Joined: Mar 8, 2008
    Posts: 116


    thanks for the input.looks like i will getting to know the shrinking disc real soon.If it comes to it they make a spray on bondo but i dont it will come to that.
  20. John_Kelly
    Joined: Feb 19, 2003
    Posts: 535


    Don't practice on your car! Make some dents in small junk panels and fix them to get a feel for the work. Parts 9-12 of my you tube videos in my signature below show a good practice piece. The shrinking disc alone will not fix the waves you have, but it will make it a lot easier.

  21. djust
    Joined: May 31, 2006
    Posts: 1,230

    from Oklahoma

    I need to get a 29 sedan blasted to and am afraid of the same thing happening to mine.
    Soda and walnut shells won't take off rust which is what I need removed but I know sand is way to harsh.
    A place here in OKC called AA Drystrip was recommended to me and are supposed to do a lot of old car bodies.
    I think they use some kind of plastic media that is not supposed to get as hot as sand and they say they know what they are doing.
    Not sure if they will guarantee not warping the body or not but I doubt it.
    I have most of the rot replaced already but need to fill the roof with a top off of a old wagon but he metal is thinner than the original body so I am not sure if I should have done before or after I get the roof filled?
    I also need the inside and out side done I guess I will just cross my fingers and hope it comes out okay.
    Don't have a any experience with wavy metal this is my first build and I am still learning how to put in patch panels that look decent.
    If it comes back all wavy just getting another body won't be an option so I hope it all goes well.
  22. joel torres
    Joined: Mar 22, 2009
    Posts: 819

    joel torres

    when i sandblast parts like a-arms and chassis i use playsand for like a kid playground as its very even in media size and does not have any garbage in it
    to blast a body i recommend soda blasting
    how bad are the waves on your body is it just door skins which are very thin or cowl and quarters and stuff
    my buddy had a door that was wavy from sand blasting i ended up replacing the whole skin which really really sucks
    im going to use on my next car when i have rust and no paint to remove
  23. Bucksnort
    Joined: Dec 24, 2007
    Posts: 3,308


    No pro here but have done a fair share of blasting along with my buddy Racemad55.We use Black Beauty,extra fine or fine,and have been fortunate to not have warpage problems.
    Did my 57 wagon,completly stripped with Black Beauty,and it came out with no warpage.And that includes the roof.If a clown like me can do it,you can.
    Don't go crazy with the pressure and be in a hurry.It is a long process.You have to keep the gun moving,a 45 degree or more angle and watch your distance.It is a constant adjustment as you move along.Just some common sense things.
  24. coopsdaddy
    Joined: Mar 7, 2007
    Posts: 884

    from oklahoma

    i have had 2 blasted and its safe if your carefull,people blast cars every day that turn out good,just get good refrences,any body can pick up a blaster and say they can blast you car
  25. I don't know if this service is still available but I've had bodies and parts acid tanked before . Gets into crevices that blasting doesn't and they usually have an after dip process to neutralize any rusting . Probably not real cheap these days with environmental controls but better than blasting any day .
  26. coody
    Joined: Mar 8, 2008
    Posts: 116


    like joel said play sand works great and you can get it anywere.soda gets paint off but not rust sugar sand is used to remove rust.dont get screwed like i did get the names from the blaster and call and get there opinion on the work they had done.go see if there are using sugar sand not just sand.I dont mind doing body work and learning from from my mistakes but i make enough mistakes on my own to keep me
  27. MERC 55
    Joined: Mar 26, 2007
    Posts: 277

    MERC 55

    Just a hello, Jack
  28. pitman
    Joined: May 14, 2006
    Posts: 4,682

    from Hampsha

    Yep, good stuff. They make locally, from coal firings, filtered in sizes for different uses. You might find it near a coal-fired Elec. power plant for sale. It was easy to make a panel "spot" glow red, and then learned to back off and stay at ~45 degrees. After prime and paint, no new rust ever appeared.

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