Tig Welding Roll cages

[wldrmike]

I have been Tig welding aircraft engine components for five years now and have started racing, and I am going to build some chassis, my question is this everything I Tig weld at work is purged. Do you need to purge mild steel tube when welding roll cages? Thanks for any assistance you can give me.

[imported_Blackplague]

Most the car builders

That i know don't. I don't think they do that with chromolly either.

[ASKANDY]

Welcome Magman,

The quick answer is no. You don't have to back purge the roll cage on mild steel. It's nice if you can because of the added protection you would get from it but in reality, none of my NASCAR teams that TIG weld the chassis are back purging. Some are drilling a small vent hole on the back side of each tube section to prevent internal pressure that causes some problems at the end of your weld. If I were doing Chr/Moly I think I would try to do it if possible.

What series are you planning on racing in?

Andy

[wldrmike]

Andy I race in a local asphalt Super truck series. The reason I want to tig the cages is because of the better quality welds, and I hit hard last year at I-70 in Odessa Missouri and whoever welded the cage was cold in a few places and the tube broke. I want to be as safe as possible so I'm going to TIG them from now on. Also what type of filler metal would you use for mild steel?

[illuzion]

I would probably use ER80S-D2 for mild steel, due to its high tensile strength and impact values, here is an excellent link that describes most of the filler metals and their differences in plain english. http://www.tigdepot.com/products/p29.html
-illuzion

[wldrmike]

Thanks

I just wanted to say thanks to Andy and all the others that have helped with my question, there's a real group of professionals on here. I have been welding for about seven years and love the power of Blue.

[Smactek]

Thanks for the link illuzion. Excellent reference site.

[ASKANDY]

Mag,
Both the ER80S-D2 and the ER70S-2 performed well in destructive testing on chassis. I would not go any higher than the ER80 because you start to lose elongation at the weld. For most mild steel chassis we do we use the 70. It also costs less.

Good luck


Andy