Welding and Metalworking - PLEASE HELP ME: Mig welds are "mushrooming" will they cool?

I am in the process of welding in a roll cage in my new Drag Car and my Mig welds sometimes "mushroom" up while they are cooling ?sometimes they are perfect looking and every now and then they do this "the center of the weld puffs up in the middle and are a bit hollow in them center of the mushroom looking thing.Any tips would be very helpful as when I go to welding the rest of the cage none of the welds can be grounded because of the rules of the NHRA for the class Im in.Please help me out here.new to forum Thanks for ALL advise or suggestions.

Jason

mushrooming MIG welds?

are you sure you are not speaking of a flux core wire welder?

I went and purchased a roll of mild alloy steel wire #70s-6 two pound roll, mild to low allow steel use?It only does it every now and then,but I cant have it do it on the cage welds as I can not grind on them after I weld them.Thanks for any help.
Jason



mushrooming MIG welds?

are you sure you are not speaking of a flux core wire welder?

You tell me what I have,it is a CLARKE 160EN Gas/No Gas mig welder that runs off of 220 volt connection?I have a small argon/mix tank and pressure gauge with a regulator set a about 9 lbs. of argon ,coming out of my gun?What is the difference in a "Flux Core wire welder and a Mig,I was under the impression it was a Mig Welder?Please clarify for me.Thanks in advance for your knowledge.


mushrooming MIG welds?

are you sure you are not speaking of a flux core wire welder?

Wire is available in different alloys and is available as a solid wire or with a flux core for welding without a shield gas. You can use a flux core wire when using gas but your results are not as pretty.

Is your weld area clean and free of paint or oil? Is something offgassing causing a bubble?

flux core wire looks similar to mig wire but it is hollow and filled with a flux. With a MIG, the gas shields the weld so the flux is not used but there can be problems such as pilot dane suggested.

It sounds like you are having problems with off gassing due to contamination OR may be not set hot enough to cause a very fluid weld and the weld is freezing before it has a chance to flow properly. Have you tried cranking up the voltage a bit?

I re-read the thread and see that it is only occasionally. I would look to the gas flow problem or maybe the position of your weld is causing the gas to be not contained enough to shield the weld. When you get these spots, what position are you welding in; flat, vertical up, vertical down, overhead?


what gas mix are you using?

is the gas flowing well?

are you in a protected area so the shielding gas is not blown away?

It sounds to me like your not welding a clean surface or if your welding outside the wind may be blowing your shielding gas away.

Jim

from experience shielding gases do not work well with contaminated material and or under windy conditions.

other circumstances when weld a tube or a pipe the heat generated makes a chimney effect pulling your shielding gases away, some times just plug the opened ends of the pipe/ tube you are welding on and the problem is solved, increasing your gas flow could also help. some people in the high tech will even fill their tubes with argon from the inside...over-kill for a roll cage i think...

good luck ;o)

some people in the high tech will even fill their tubes with argon from the inside...over-kill for a roll cage i think...

good luck ;o)

why? Nitrogen prevents oxidation or oxygen inclusion, which weakens the metal, even as it is welded.

I would like my roll cage to be as strong and dependable as possible. Nitrogen is a relatively cheap method to improve the welds.

Now, there are many other items being welded that I can see it as overkill but a roll cage...?

why? Nitrogen prevents oxidation or oxygen inclusion, which weakens the metal, even as it is welded.

I would like my roll cage to be as strong and dependable as possible. Nitrogen is a relatively cheap method to improve the welds.

Now, there are many other items being welded that I can see it as overkill but a roll cage...?


you are right, a roll-cage is the right place to over kill :)

the people that i saw filling pipes with shielding gas(argon-co2-helium) were doing it to have perfect finish inside out wich was reached . saying to avoid restrictions (they were at that time doing exhaust piping for a racing bike) from what i saw it looked like it has been tig welded from both side just by adding gas inside...wich for a roll-cage may be not necessary...

by the way Jason, are you using galvanized pipes for your roll-cage?