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welding bumper mounts

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  • welding bumper mounts

    Hi. I have two welders. A miller syncrowave 200 TIG amd a Millermatic 212 Autoset. I have almost zero time tig welding, but has experience mig welding automotive sheet metal.

    I am making some chassis reinforcement for a jeep tire carrier bumper, one that needs to be strong enough for recovery shackles to pull on.

    I plan on square steel tubing, 2x3 inch, 3/16 wall thickness, and Id like to weld a flat plate 4x6 inches to the end of the square tube, The plate thickness can be 1/4 inch up to 1/2 inch. if I go the thin route, the plate will then have holes drilled for bolts and nuts to attach the bumper to the plate, or if I use thicker plate, I will thread the plate rather than use nuts.

    the square tube, about a foot long will be inserted into the unibody frame, with the end and the plate sticking out to accept the bumper.

    How best to weld the plate to the end of the tubing? The plate will be on the end, 90 degress to the axis of the tube.

    I can cut a squate hole in the plate to allow the tube to be inserted. I am thinking of beveling the hole and the end of the tube By cutting the hole and inserting the tube, I figure I can then weld on both sides.

    any advice on this? Should Mig weld it?


  • #2
    Here is a photo...


    • #3
      I'd use the wire feed and wouldn't think twice about it. Grind the surfaces, crank it up and burn it in. Done.


      • #4
        Yup. Get that mill scale off. I would spray arc that, but I don't think you're little machine will do spray arc. Not sure about that though.


        • #5
          Both machines max out at 150 ± so either is capable of making the weld. Given I'm a cantankerous old fart, I'd plug a stinger into the 200 and weld the joint with 1/8 rod.

          The problem is your lack of experience. MIG even with Co2 gas is something you're only conversant with on automotive tin, so you'll need to come up to speed on getting sufficient penetration to make the weld worth making. Forget about attempting spray on this job.
          I'd turn off the autoset crapola and do some practicing if you choose the MIG path.

          You also might want to consider equalizing stress on the unibody before playing with recoverys. Unibodys rip apart and pretzel when pulled from body structure. Axel housings are far superior pull points since they distribute load.


          • #6
            I would definitely recommend practicing if you aren't familiar with MIG welding heavier material. A friend of mine did something similar on an old CJ5. His welds looked fairly good to the uneducated, but he later broke the entire assembly off when he tried to pull the jeep out of a hole with another truck. His welds all failed due to minimal penetration.


            • #7
              Not sure if this will make sense or come across as anything close to intelligent, but what I've observed as a problem for the less then knowledgeable to grasp is how much weld you can expect to deposit from a wire that's .023, .030, .035 in diameter so it deposits properly when compared to a 1/8" stick electrode? While admittedly one has to be concerned with quench hardness, lessened fusion depth/dilution and micro structure welding thicker materials, the big problem arises with the fill it in one pass mentality, when three small ones would do a better job. All that cursive "e" mumbo jumbo, doing circles, whipping to stack dimes, stuff like that.
              I'm with Franz on this, 1/8 rod, weld it and be done with the suffering. Having said that, if buddy brought it to me, tack, tack with the HH135 and .030 with mixed gas. On the simple, how much material is missing between the two surfaces if it was to be one solid piece? I'm sure a small properly placed fillet welded all around could do that. Where's it going to go? Awhile a little good weld hold more then a lot of bad, if the fear is bad welds, the cure is practice with understanding of what your doing , how it being done, the reason for it being done that way.


              • #8
                Another mildly important with regard to a slip in fit to the unibody "frame" is that the fit needs to be tight to minimize disaster potential in a future winching operation.
                Few things in the wonderful world of off road driving is a chunk of iron at the end of a tow strap or winch cable flying through the air towards your head because somebody didn't understand connection and relied on bolts.
                We won't even entertain the concept on sails on winching & recovery lines.


                • #9
                  So what year and model "Jeep" is this?

                  Miller Dynasty 700...OH YEA BABY!!
                  MM 350P...PULSE SPRAYIN' MONSTER
                  Miller Dynasty 280 with AC independent expansion card
                  Miller Dynasty 200 DX "Blue Lightning"

                  Miller Bobcat 225 NT (what I began my present Biz with!)
                  Miller 30-A Spoolgun
                  Miller WC-115-A
                  Miller Spectrum 300
                  Miller 225 Thunderbolt (my first machine bought new 1980)
                  Miller Digital Elite Titanium 9400