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  1. #1
    Join Date
    Jun 2008
    Posts
    17

    Default Need some advice TIG welding patch panels

    In a few areas on my car I have used my MM210 Mig to weld in patch panels on the car, tacking every inch or so, jumping around and letting it cool. This has worked, but I was not crazy about all the grinding that needed to be done afterward (maybe caused by my lack of experience).

    So I was tacking a patch panel in on Saturday on my rusty quarter panel with the Mig and thought "I wonder if the Tig machine would do this a little cleaner"

    So before I move forward to use my new Tig machine on the panel, I plan on practicing a good amount on some scrap sheetmetal of similar thickness. My question: is there anything I should do specifically in Tigging thin body panels? For example, is it best to tack similar to Mig, or run a continuous bead with the Tig? I realize heat is the enemy here and do not want to warp the panel, but was concerned that even a real low amperage setting may warp the panel with a continous bead.

  2. #2
    Join Date
    Jan 2009
    Location
    Cleveland, TN
    Posts
    229

    Default

    TIG will have less to grind down, but you need the panels to fit TIGHT to do this. (like 0 gap) Practicing on scrap is always the best idea. This way you can get a good setting before you tackle the real thing. But, even with less amps you can warp the panel using TIG compared to MIG. The main reason is speed. The MIG is done as soon as you pull the trigger for tack welds. The TIG can take twice as long to tack for the novice. Even with the TIG you can't run long beads on thin stuff. Having a wet rag next to you to dab the weld right afterwards helps some, but can make the metal brittle if too much heat was applied.

    Do you have .023 wire in your MIG? It works the best for body panels. For grinding down the weld I use a thin (3/32nd thick) cut off wheel in a die grinder, but a 4 1/2" angle grinder with a cut off works also. This way you only remove the filler not the metal in the panel, and it keeps the heat down.
    Dynasty 200 DX runner
    Sync 350 LX
    XMT 300 w/D74 and roughnecks
    Hobart 135
    ESAB PowerCut 875 plasma

  3. #3
    Join Date
    Jun 2008
    Posts
    17

    Default

    Thanks. Yeah, I have been using .023 wire in the Mig. Good tip on grinding, will have to try that. I just figured this was a perfect application for me to put the new machine to use on. I realize it will be slower, but if the end product is better or at least less painful to get to (ex:less grinding), I thought it would be worth it.

  4. #4
    Join Date
    Jul 2007
    Posts
    241

    Default

    If you are tig welding in patches On your ''rusty quartepanel'' you better cut your panel back to clean steel if you plan on making good welds with tig. The areas where you plan to attach donor panels to will probably have some porosity and contamination which will defeat the purpose of tigging them.You are going to fiind out first hand why body shops use mig instead of tig.if tiigging was the way to go more shops would do it.Also butt welded panels have to be fit up perfect or you will burn lots of holes trying to get a puddle started,If the fit up is perfect you can make some very nice precision welds on 18 guage.Just think that if the grinding is getting to you,how about the Body filler and 2K block sanding you will have to do to get the panel smooth? I dont think the tigging is the answer that you may think it is for auto sheetmetal.Mike

  5. #5
    Join Date
    Oct 2004
    Posts
    119

    Default

    The blocking and priming isn't an issue. Not that I dislike the grinding, just makes me nervous that I spent a lot of careful time trying not to distort the area during the welding process that I am afraid I will create too much heat during grinding. I have seen it happen on a friend's car. For some reason he did not realize the amount of heat that builds up, had to do a lot of hammer/dolly work to get it back. I figured the Tig may help reduce that chance, but you do bring up some really good points.

    I have the Tig machine right next to the Mig, so I will practice on a couple of scraps at first and see how I feel. May not even mess with it on the car if I do not feel comfortable.
    ________________
    Greg

    Miller 210
    Diversion 165

  6. #6
    Join Date
    Jan 2009
    Location
    Cleveland, TN
    Posts
    229

    Default

    You will have to do some hammer and dolly work from the welding reguardless, but using cut-off wheels for the grinding eliminates heat during that part of the work.
    Dynasty 200 DX runner
    Sync 350 LX
    XMT 300 w/D74 and roughnecks
    Hobart 135
    ESAB PowerCut 875 plasma

  7. #7
    Join Date
    Aug 2008
    Location
    Macon, Ga
    Posts
    13

    Default

    I use both mig and tig for body panels. I prefer the tig for small patches and mig for larger work like quarter panels and floors.
    I also like the 4 1/2 flapper disk over the grinding disk, it also helps to move around while grinding just like you do when welding.
    Hope this helps DD

  8. #8
    Join Date
    Jan 2009
    Location
    Cleveland, TN
    Posts
    229

    Default

    Depending on the panel size I use the "flapper", or 2" 50 grit disc on air grinder after getting the bead knocked down close to panel with the cut-off wheel.
    Dynasty 200 DX runner
    Sync 350 LX
    XMT 300 w/D74 and roughnecks
    Hobart 135
    ESAB PowerCut 875 plasma

  9. #9
    Join Date
    Dec 2008
    Location
    Arizona
    Posts
    812

    Default

    I TIG welded this crotch rocket fuel filler cap into my Jeep CJ-5 body.


    I used a butt weld and fit it up good, bet I didn't have to use a 1/2 teaspoon of body filler! Go slow, allowing your welds to cool, skip around, use .040 tungsten for the thin stuff.
    Miller Syncrowave 200
    Homemade Water Cooler
    130XP MIG
    Spectrum 375
    60 year old Logan Lathe
    Select Machine and Tool Mill
    More stuff than I can keep track of..

  10. #10
    Join Date
    Oct 2004
    Posts
    119

    Default

    All great advice, thanks guys. This coming weekend I will mess with both. Since I have one part of the quarter already patched using the Mig, I still have to grind down the welds and will using the advice you guys provided. I will also spend some time messing with some thin scraps with the Tig and see how I do. Who knows, maybe it will work out better for me, at least it will give me more of a reason to tell the wife I need to go out in the garage to practice more
    ________________
    Greg

    Miller 210
    Diversion 165

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