Over the last few weekends I have been welding up the frame of a 1/4 scale tractor and ran into a problem this last Saturday. The frame is made of .050 in mild, and should be somewhere between 1010 and 1020 steel(a lack of organization in the place that laser-cut it contributed to this). Amperage is around 50, with high freq start and a smaller/medium sized(3/8 in opening) cup. I am using .040 thoriated tungsten (sharpened) and started out using normal .035 in mig wire (70-S6 I believe) as filler. This worked fairly well, but the natural curvature of the wire made for difficulty in controlling the placement, so i figured I would try to use some straight 1/16 filler rods instead. This is where the problem occured- no matter what the joint configuration was (some open root butts, others were edge, and even some TEEs), the weld pool bubbled like a cauldron. Tacks had caverns large enough for someone as vertically challenged as me to make a fairly nice home in. Adjustment of flowrate up and down did not seem to help, and intensive cleaning far beyond what I was doing when using .035 wire had little effect. I even wiped down the 1/16 rod with acetone thinking maybe it was contaminated with grease or oils.
I ditched the effort and went back to clipping the .035 from the MIG for this reason as well as the fact that the rod was just too danged big, but have no clue as to why the 1/16 would not work right. Any insights or theorys would be appreciated.
Thanks in advance and all of ya'll who make this such a great forum,
G. L.
it could be that the 1/16 rod you were using was designed for oxy/fuel welding instead of tig. there is a difference in these rods, where the composition is changed. I don't have all of the specifics, but this could be the root of your problem. did you notice if the arc had any "spatter" coming off of the rod? tig welding should be 'clean and quiet', with no sparks coming off of the weld. this usually indicates contamination of some sort, either in the base material or the filler rod. I would reccommend trying your supplier and getting some 70S-2 tig rod to try out. it is available in smaller diameters.
Sparx,
I didn't know that there was a difference, but that explains this case perfectly (a guy I work with picked up the filler, which had no documentation with it, just a rubber band holding them together...), and considering the Fourth of July show that was occuring in the puddle, yes, you hit the nail on the head. Thanks!
G. L.
tigger, two things, you may want to make sure that your wire is for tig and also you are using 70-s6,you can also get this wire in smaller sizes and will weld a little better than the s2 wire. This sounds silly but make sure that the workpiece is clean and free of contamination.
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