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Grinder Use-

Discussion in 'Intermediate CJ-5/6/7/8' started by Ricardo77, Apr 18, 2008.

  1. Apr 18, 2008
    Ricardo77

    Ricardo77 New Member

    Los Angeles
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    I started to take off the paint of some of the panels of my 73 where I have minimum rust with a grinder.. but one thing led to another and now I have the right front fender shiny -the whole thing..to the bare metal with this grinder.. a friend told me this is the wrong way to do it as when the car is primer all of the lines and circles will show .. I was going to use different sand paper to make it smooth. is this the worng way to go ??
     
    Ricardo77, Apr 18, 2008
    #1
  2. Apr 18, 2008
    LarryD

    LarryD Member

    Gallup NM/ 4 Corners
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    Yes the circular marks can show thru, Body shops use a DA, dual action sanders, they have 2 settings, rotary and second an offset rotary, the second setting allows the disk to rotate but offset, this reduces the swirl marks.
     
    LarryD, Apr 18, 2008
    #2
  3. Apr 18, 2008
    DrDanteIII

    DrDanteIII Master Procrastinator

    Milford NJ 08848
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    Are you using a grinding wheel or a flap disk? The Flap disk is much more forgiving on the metal beneath.

    Just get sandable filler style primer, do a few coats and sand it smooth. Heck the pannels on jeeps wern't smooth from the factory.
     
    DrDanteIII, Apr 18, 2008
    #3
  4. Apr 18, 2008
    Ricardo77

    Ricardo77 New Member

    Los Angeles
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    Well I am using the grinding wheel for the frame but for the body I am using this blue color wheel from Home Depot that looks like a hard sponge.. any ideas ? I do not know what a flap disk is.. but I will look into that.. so they do have primer that u can sand to a smooth finish eh??
     
    Ricardo77, Apr 18, 2008
    #4
  5. Apr 18, 2008
    timgr

    timgr We stand on the shoulders of giants. 2022 Sponsor

    Medford Mass USA
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    Yep, it's called filler-primer or something similar. I think you'll need to use a harder primer (like epoxy primer or etching primer) underneath it - just follow the manufacturer's recommendations.
     
    timgr, Apr 18, 2008
    #5
  6. Apr 18, 2008
    Ricardo77

    Ricardo77 New Member

    Los Angeles
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    I will try to take some pics over the weekend to show you guys how it looks .. should be up by sunday afternoon.. I have done one panel and most of the floor panels...so base on info here is is better to sand by hand than ??
     
    Ricardo77, Apr 18, 2008
    #6
  7. Apr 18, 2008
    Howard Eisenhauer

    Howard Eisenhauer Administrator Staff Member

    Tantallon, Nova...
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    If you can feel the circles with your finger tips they'll show through paint, I have plenty of swirl marks on Tonk but although visible the metal is smooth to the touch. If you can feel them high build primer will make'em disappear pretty fast. The flapper disk does a better job but you have to be careful with either not to over do it, they'll both turn sheet metal into metal foil in pretty quick order, thats probably the hardest lesson I learned on welding body panels :(.

    H.
     
    Howard Eisenhauer, Apr 18, 2008
    #7
  8. Apr 19, 2008
    Ricardo77

    Ricardo77 New Member

    Los Angeles
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    Thanks Howard ...good info..
     
    Ricardo77, Apr 19, 2008
    #8
  9. Apr 19, 2008
    kaiser715

    kaiser715 Member

    Sanford, NC
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    Be careful too -- you can get enough heat into a panel to warp/deform the sheetmetal with a grinder.
     
    kaiser715, Apr 19, 2008
    #9
  10. Apr 19, 2008
    Ricardo77

    Ricardo77 New Member

    Los Angeles
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    I know its one of those things that worry me ...I guess only the underside will get hit with the grinder and the frame..
     
    Ricardo77, Apr 19, 2008
    #10
  11. Apr 19, 2008
    Howard Eisenhauer

    Howard Eisenhauer Administrator Staff Member

    Tantallon, Nova...
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    Actually, for taking paint off the flat parts I've found that nothing works better than a belt sander :twisted: For the curvy parts a wire brush on the grinder works well, but get the brush from an industrial supply place, the ones showing up at flaps/hardware stores lately disintegrate prety quickly, you'll actually spend more time un-embeding little wires from your hide than spent paint removing. I won't tell ypu how I know this but lets just say I now have a lot of sympathy for how voodoo dolls earn their living :(.

    H.
     
    Howard Eisenhauer, Apr 19, 2008
    #11
  12. Apr 19, 2008
    Hi5nCJ

    Hi5nCJ Hi5nCJ

    Omaha, NE
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    Ricardo77, If you plan on doing quite a bit of body work I would strongly recommend buying a D/A sander. I would also shy away from using the grinder on any sheetmetal, they (even with a flapdisk) are way to aggressive and heat up the metal to much too quickly. Grinding on the frame is ok but don't get too crazy with it. Good luck on the rest of the build:beer:
     
    Hi5nCJ, Apr 19, 2008
    #12
  13. Apr 19, 2008
    Ricardo77

    Ricardo77 New Member

    Los Angeles
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    Thanks//Yeah.. I think I should have posted this first before grinding away ...and howard I red your use of needles somewhere I think.. lol
     
    Ricardo77, Apr 19, 2008
    #13
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