Just joined? Please introduce yourself.
Page 3 of 3 FirstFirst 123
Results 21 to 26 of 26

Thread: Replacing floor boards, firewall & welding exhaust

  1. #21
    Registered Member chevynut's Avatar
    Join Date
    Nov 2011

    Member #:115
    Location
    Fort Collins, CO
    Posts
    10,835
    I learned a lesson about sandblasting on my Nomad. I chemically stripped the body panels, but the window and door openings with all their tight bends, etc. were difficult to do. Plus I didn't want any chemical stripper left in any nooks and crannies. So I blasted those areas.

    After blasting the edges of my hood I decided to blast the rear hood brace. I should have put a sheetmetal protector between the brace and the outer skin, but I tried to be careful not to blast the underside of the skin. I was using pretty low pressure....probably 80 PSI or less at the blaster, and 80 grit silica sand (don't lecture me on the health effects please ). My hood was virtually perfect.

    Here's a pic of the underside after blasting:

    Picture 142.jpg

    Picture 412.jpg

    I also did the same with the roof brace....notice I barely hit the roof skin:


    Picture 206.jpg

    After priming I started blocking the parts some time later. I was baffled as to why I had a big dip at the back of the hood. It was literally 1/16" deep and I had to bodywork it and use Slicksand to get it back to where it should be. I couldn't figure out why it was low there for quite a while.....I think it was when we were discussing a trunk lid that got ruined by sandblasting on the other site. Then it hit me. Also, when I blocked out the roof there was a slight low spot in front of the brace. I'm convinced that you should NEVER touch flat sheetmetal with a sandblaster, no matter how "careful" you are.

    Here's the hood after blocking Slicksand:

    20120207_0009.JPG

    Bodyworking:

    20120210_0008.JPG

    Finished:

    20120225_0008.JPG
    Last edited by chevynut; 03-29-2018 at 07:47 AM.
    56 Nomad, Ramjet 502, Viper 6-speed T56, C4 Corvette front and rear suspension


    Other vehicles:

    56 Chevy 2-door BelAir sedan
    56 Chevy 210 4-door sedan
    57 Chevy 210 4-door sedan
    1962 327/340HP Corvette
    1961 Willys CJ3B Jeep
    2001 Porsche Boxster S
    2003 Chevy Silverado 2500 HD Duramax
    2019 GMC Sierra Denali Duramax

  2. #22
    Registered Member BamaNomad's Avatar
    Join Date
    Nov 2016

    Member #:3217
    Location
    Rocket City, USA (Huntsville, AL area)
    Posts
    3,774
    It seems you were removing Paint rather than rust, Laszlo?? Rust comes off quickly with the sand blasting, but paint is VERY SLOW to be removed, and I suspect that is where the warpage is coming from... I would not use a sandblaster to remove PAINT... I only use sandblaster to remove RUST...

    Gary

  3. #23
    Registered Member
    Join Date
    Mar 2017

    Member #:3360
    Location
    Canton,Ohio
    Posts
    260
    So is it best to remove the paint first or the rust?

  4. #24
    Registered Member chevynut's Avatar
    Join Date
    Nov 2011

    Member #:115
    Location
    Fort Collins, CO
    Posts
    10,835
    Quote Originally Posted by BamaNomad View Post
    It seems you were removing Paint rather than rust, Laszlo?? Rust comes off quickly with the sand blasting, but paint is VERY SLOW to be removed, and I suspect that is where the warpage is coming from... I would not use a sandblaster to remove PAINT... I only use sandblaster to remove RUST...Gary
    I find paint comes off easy with a sandblaster.....easier than rust. The paint on my hood brace was very thin and I don't even remember if there was any on the roof brace. I don't think there was any rust, or very little. If you're only blasting paint, you won't warp the metal. It occurs when you actually HIT the metal. Warpage from sandblasting is caused by the sharp particles "peening" the metal on one side, thereby stretching it only on that side. That's why I had a dip in those places....when the metal stretched it moved TOWARD the blaster nozzle.

    On the other site a guy has his car sandblasted. He showed pics of a "ruined" trunk lid that had dips at every opening in the underside brace. What happened is the blaster blasted the underside of the lid, and hit the outer skin, stretching the metal. You can prove this to yourself with a blast cabinet. Take a flat piece of sheetmetal and blast one side. It will "cup" toward the blaster nozzle. Flip it over and blast the other side....it will straighten out. I've actually used my blast cabinet to fix oilcanning of some smaller parts like covers, etc. by blasting them and stretching where needed. I use glass beads in the cabinet.

    This is the car after stripping pretty much all the paint I removed with stripper:

    10120006.JPG

    This is after blasting (I replaced both quarter panels):

    20060723_005.JPG
    56 Nomad, Ramjet 502, Viper 6-speed T56, C4 Corvette front and rear suspension


    Other vehicles:

    56 Chevy 2-door BelAir sedan
    56 Chevy 210 4-door sedan
    57 Chevy 210 4-door sedan
    1962 327/340HP Corvette
    1961 Willys CJ3B Jeep
    2001 Porsche Boxster S
    2003 Chevy Silverado 2500 HD Duramax
    2019 GMC Sierra Denali Duramax

  5. #25
    Registered Member
    Join Date
    Mar 2017

    Member #:3360
    Location
    Canton,Ohio
    Posts
    260
    Thanks CN I hope to be able to start on my body soon, I'll try to post before and during pictures. Thanks to all you guys!!!

  6. #26
    Registered Member
    Join Date
    Aug 2013

    Member #:1806
    Posts
    414
    All paints are not the same, some are easy some are not, and the same is true of rust. Pitted rust is hard to remove, depending on the depth of the pits. Blasting sheet metal with a radius is safer than blasting a hood.

    Blasting media is also deferent, sand is hard and sharp, crushed glass is not so hard but it is still sharp, glass beads are not hard and not sharp, but they don't work well for this application, so I don't think its a good idea to recommend that anyone can blast sheet metal without any problems. JMO
    Last edited by LEE T; 03-29-2018 at 09:18 AM.

Page 3 of 3 FirstFirst 123

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •