I have a set of 35 rear wishbones the are cracked about 18" down the middle of the factory seam weld. I ground down the original weld and v notched the crack. I tried Tig welding with straight argon and Mig welding with argon/carbon dioxide mix and still I get a constant spitting up from what appears to be some type of contamination. I also took my torch and heated the whole area cherry red in order to burn out any oil etc that might be imbedded in the metal and was no help. The welds that I get are full of pin wholes and look crappy. Any one have any ideas?
Did you see my tech thread? I have pics and tech about welding up the factory seams, it is a pain for sure. The factory weld was good for it's time, but it and rust that get inside make it hard to do. Maybe get it fairly decent, grind smooth and run another bead over it for cosmetics.
I wish - got direct ground and verified the gas flow - and welded other parts since with no problem. I also tried welding an area off of the original weld with same spitting and popping.
Try shielding the back side of your weld (the inside of the tube) with another argon bottle and regulator. Drill a small hole for gas in and another to let the expanding gas out.
Is it the black fluffy stuff that the insides of wishbones are full of? I have cut '36 bones and always get black powdery stuff (forge scale...??) falling out. Welding them seems to work fine foe me though. I boxed a Model A frame that was NICE; no rust or rot. But the welding drove me nuts because of the impurities that forced bubbles out much like what your saying. I thought it was my welder, and frantically checked gas, wire, feed, and even ground. Welder was fine. What I should have done is cleaned the inner channel of the frame sides thoroughly. I am sure there was something in there that was gassing from the weld heat.
There is no way to clean the other side of the weld area (the inside of the tube). If you are getting 100% penetration, then you are pulling contaminants from that side into the weld. Shielding the back-side would only help if that side were clean.
You say the tube is cracked at the factory seam? it isn't from frozen water is it? If 'yes' then you got rust inside the tube - no help for that. If it is rust then you'll want to figure a way to see how much wall thickness is left, just thinkin. If it ain't rust you can try to add a vent hole away from the weld so that the internal pressure can release itself in a spot other than the weld itself.
I had the same problem i ended up cutting the big end off and hot tanking the hole thing a couple of times and a ton of crap came out cleaned it up and it welded fine then put the big end back on. Clay >>>>>>>>
Welded some seam split bones many years ago, I used 6011 stick for first pass. That worked OK for me.
Go hot, deep and fast, 1st weld will look crappy. 2nd weld will look better, 3rd will be nice. Lay it in there...their stuff was good for the day but shitty by our standards. Remember them welding with cloths hangers and such? Theres all kinda crap they used to pull....
my guess is its the rust inside the tube contaminating things.Assuming you have removed all of the original weld, I would use MIG, (which is more forgiving of rust/imperfections)and as suggested, run a second line from your argon/CO2 to the tube and run a slow trickle of gas in there too.Grinding out your first pass and going again will help too. you probably wont end up with as clean a weld as you would hope, but it will be strong enough..the original ford welds are very often full of bubbles and stuff, and they dont seem to fail.
I took the advice and ground out the first pass. The second pass looked better. Tomorrow I will grind down the second and put in a third. I hope that will do it! 117harv - I love what you did - you are a craftsman.
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