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Hot Rods sheet metal welding for autobody

Discussion in 'The Hokey Ass Message Board' started by old_chevy, Jun 30, 2020.

  1. old_chevy
    Joined: May 28, 2012
    Posts: 84

    old_chevy
    Member
    from USA

    I have some esab easy grind .023 wire. What do you recommend for grinding down the weld for sheet metal? Also for butt welding two sheet metal panels what do you recommend for the gap width between panels?
     
  2. squirrel
    Joined: Sep 23, 2004
    Posts: 55,931

    squirrel
    Member

    If you plan to butt weld sheet metal with a MIG....I suggest you practice a lot, and figure out what gap works best for you.

    For grinding lap welds, don't grind too far, or the strength goes away. I usually use a coarse flapper wheel or 36 or 80 grit roloc disk.

    That's a long ways above my skill set!
     
  3. Budget36
    Joined: Nov 29, 2014
    Posts: 13,173

    Budget36
    Member

    I try not to leave any gap when butt welding.
     
    31Apickup likes this.
  4. A wide cut off wheel in a die grinder so you can just take the top of the weld off and not a bunch of the surrounding material.
     

  5. Fortunateson
    Joined: Apr 30, 2012
    Posts: 5,331

    Fortunateson
    Member

    When bringing down welds only grind the proud area/part above the rest of the sheet metal. Use the edge of the grinding wheel or cut off disc. And move around so the heat doesn't increase too much.

    You may want to check out Fittzee Fabrications on YouTube. He presents a overlap method that really tightens the gap up when welding up patch panels. Plus he uses basic tools...
     
    Last edited: Jul 2, 2020
    jakespeed63 and missysdad1 like this.
  6. ZERO gap. The easiest weld is a file fit no gap weld. Fitting metal like that is the easiest method once you get used to it

    I use a die grinder with a thick cutoff wheel to grind JUST the weld then hammer and dolly followed by a 40-50 grit grinding disc.
     
  7. old_chevy
    Joined: May 28, 2012
    Posts: 84

    old_chevy
    Member
    from USA

    for a butt weld on a sheet metal panel don't you want some gap otherwise the metal will expand and bend
     
    Departed likes this.
  8. mickeyc
    Joined: Jul 8, 2008
    Posts: 1,363

    mickeyc
    Member

    I have tried to find the easy grind wire for
    some time to no avail. Most distributors I
    approached are not even aware it exists. I
    would appreciate some information on where to obtain this wire. Thanks.
     
  9. rusty valley
    Joined: Oct 25, 2014
    Posts: 3,883

    rusty valley
    Member

    zero gap, and if you have access you want to whack it with a hammer and dolly after you go an inch or so, this will shock the weld and hopefully slow down the shrinkage which pulls as it cools and causes warps
     
  10. Budget36
    Joined: Nov 29, 2014
    Posts: 13,173

    Budget36
    Member


    I looked years ago as well locally. Also noticed no places sold ESAB products locally either.

    I bet it'd be easy to find through Amazon, etc?

    Heck, no I'm gonna go look;)

    Edit:

    Couldn't find it on Amzon, but did on the AirGas site:


    Sorry, can't get the link to post, go to www.airgas.com and do a product search for "Easy Grind"
     
    Last edited: Jul 1, 2020
  11. old_chevy
    Joined: May 28, 2012
    Posts: 84

    old_chevy
    Member
    from USA

    I got the easy grind wire maybe 10 years ago online. It is made by esab. Here it is for sale. Crazy money. I don't remember it costing that much.

    https://weldingsupply.com/cgi-bin/einstein.pl?PNUM::1:UNDEF:OR:130PS43#ezScrl1
     
  12. old_chevy
    Joined: May 28, 2012
    Posts: 84

    old_chevy
    Member
    from USA

    my gaps are about the width of a nickle in thickness. some places more.
     
  13. rusty valley
    Joined: Oct 25, 2014
    Posts: 3,883

    rusty valley
    Member

    thats gonna be tough to fill without creating a lot of heat. if you have access to the back, a chunk of brass on the back will help keep it cool and leave a smaller mess to grind off
     
    loudbang likes this.
  14. brigrat
    Joined: Nov 9, 2007
    Posts: 5,615

    brigrat
    Member
    from Wa.St.

    Don't expect miracle's with it!
    DSCF0974.JPG DSCF0975.JPG
     
  15. 1946caddy
    Joined: Dec 18, 2013
    Posts: 2,059

    1946caddy
    Member
    from washington

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  16. Fortunateson
    Joined: Apr 30, 2012
    Posts: 5,331

    Fortunateson
    Member

    I looked into Easygrind and the comments were about fifty fifty regarding how good it is. Most said it wasnt worth the cost. Same thing when I talked to guys locally. And I believe a tiny gap is required when butt welding sheet metal as when the metal gets hot it expands so when the weld is made it will cool off afterwards which will cause it to shrink. I believe if there is no gap at all there won't be any allowanace for the wire when the weld is made and you'll have trouble. Now perfect fitup for gas and or tig is recommended.
     
    Last edited: Jul 5, 2020
    rusty valley likes this.
  17. rusty valley
    Joined: Oct 25, 2014
    Posts: 3,883

    rusty valley
    Member

    ^^^^ perhaps some gap for mig. but.. i will add, you dont tell us what you are doing, so just some thoughts about big gaps...do some tacks in 3 or 4 different spots so you can jump around and be hitting a spot that has cooled. a wide gap will be basically spot welding to keep from making holes and lumps of weld, so move around and let it cool
     
  18. old_chevy
    Joined: May 28, 2012
    Posts: 84

    old_chevy
    Member
    from USA

    I should have clarified, I just have a mig welder with gas setup. Its an older Miller 120v welder with low hours.
     
  19. old_chevy
    Joined: May 28, 2012
    Posts: 84

    old_chevy
    Member
    from USA

    good thinking. the large gaps between the butt joints are in the floor. I can reach under the floor and use some copper behind it as I weld.
     
  20. rusty valley
    Joined: Oct 25, 2014
    Posts: 3,883

    rusty valley
    Member

    i am a big miller fan, old stuff, millermatic 200, and a dial arc hf tig. never a fan of 120v welders, but atleast you have gas shielding, thats a must have, and for sheet metal you will get it done.
     
  21. old_chevy
    Joined: May 28, 2012
    Posts: 84

    old_chevy
    Member
    from USA

    I have an older 70s truck that I have cut out rust and am welding patch panels. I have a Miller mig welder with gas and a 220v Dayton spot welder. I still need to tack weld. My plan is to use a wet rag and or compress air to keep it cool.
     
  22. old_chevy
    Joined: May 28, 2012
    Posts: 84

    old_chevy
    Member
    from USA

    Its a Millermatic 130xp 120v 20 Amp. I have it on a dedicated 20amp circuit. I'm going to be welding outside so I will need to find some way to keep wind away as I weld.
     
  23. jetnow1
    Joined: Jan 30, 2008
    Posts: 2,152

    jetnow1
    ALLIANCE MEMBER
    from CT
    1. A-D Truckers

    I am not the welder that many here are, so I can only say what worked best for me. Welding the patch panels on my 50 Chevy truck the better the fitment of the panels, the better the welding and the least amount of grinding needed. The best tip I can offer you is to cut out more than you think you need to on rust, welding rust thinned steel is no fun. Cut it back to solid steel!
     
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  24. brsturges
    Joined: Oct 22, 2008
    Posts: 931

    brsturges
    ALLIANCE MEMBER
    from Miami, FL

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  25. fresh hops
    Joined: Oct 19, 2019
    Posts: 67

    fresh hops

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  26. WTF really
    Joined: Jul 9, 2017
    Posts: 1,322

    WTF really
    Member

  27. a zero gap will not affect shrinkage more than welding with a gap.. A weld with a gap will require more wire thus more heat producing more distortion
    We are not welding battle ships, just thin sheet metal.
    With zero gap you use less wire with less heat being used to make the weld.
    The weld is smaller and takes less time to grind, again less heat.
    The smaller the weld, the easier it is to metal finish.
    The time it takes to make the no gap butt joint is gained on the grinding and finishing side. You dont need easy grind mig wire when you have a proper weld on sheet metal.
     
    Last edited: Jul 1, 2020
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  28. DIYGUY
    Joined: Sep 8, 2015
    Posts: 883

    DIYGUY
    Member
    from West, TX

    Wow, thanks for that link! That information made the most sense to me from all the stuff I have read combined with my recent experiences. (I'm talking about the instructions from Robert at the end, really don't care about the ezg)
    No amount of skipping around and cooling has helped me. If you weld it, it will shrink. Also, the planishing, seems when I hammer the weld on dolly, the panel wants to sink rather than raise. Access to the back side is so important.
     
    anthony myrick likes this.
  29. for both mig and tig I like to hammer and dolly as I go.
    after finishing the weld I will grind ONLY the weld. Then more hammer and dolly work. A good tig or gas weld will not need much weld grinding, it usually flows or planishes into the metal relieving the shrink.
    I especially recommend hammer and dolly while mig welding because you can manage the distortion better. A mig weld is harder than the sheet metal its welding and can crack. Relieving as much distortion during the weld can help prevent this in my worthless opinion.
    I never force cool a weld. Cooling a hot spot in sheet metal is how you shrink it.
    you can NOT stop the laws of physics, you have to use them. The weld shrinks the metal, hammering stretches the weld area.
    I do not weld on a panel until I work the dents and distortions. That way any changes that happen after the weld can be attributed to the weld. If a low spot shows up after welding on the other end of the panel, the weld caused it. Do not attempt to address the the low spot until after the weld is worked.
    The sinking in during the hammer and dolly work can be a sign of over working the weld. I use a small head ball peen hammer to work the weld area only. I do not want to hit beyond the heat affected zone. A large face body hammer can sometimes do that.
     

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