how many of you guys have mild steel cages ? whos got chromoly ?

I used some mig wire,.035,to tig some thin stuff.the mig wire is er70s6 where the tig rod is er70s2.it worked ok for me.

I don't understand why NHRA requires CM be tig welded. NASCAR chassis are mig welded and those guys wreck the shit out of those cars with no problems.

When I worked for a nascar team our cars were mild steel & mig , no cm

sg86coupe wrote:When I worked for a nascar team our cars were mild steel & mig , no cm

yep cm gets too hot if it's mig welded.

Mike R wrote:I don't understand why NHRA requires CM be tig welded. NASCAR chassis are mig welded and those guys wreck the shit out of those cars with no problems.

One reason NASCAR allows MIG welding is their stuff is mild steel and not 'moly.

And don't forget that a 'moly drag car's tubing isn't 100% .083 wall, there is also a bunch of .065, .058, & a small amount of .049" wall tubing in there too. And it's just too easy to either burn too cold, or too hot & blast holes in the real thin 'moly with a MIG. It's a fine line working with the real thin 'moly, it really needs to be finessed together with the slower Tig to more accurately control both the heat & amount of filler material deposited at the same time during the pass.

bbf-falcon wrote:I have a ? for you tiggers. If you are building a chassis or whatever.Can you spot it together w/mig and then take it to the TIG shop?

It's not the best idea but it can be done on both ms & 'moly if you put the tacks in the right place, and don't make them too big. Only problem is if you tack a chassis together, then haul it somewhere, there is no guarantee that all the tubes will still be in exactly the same place after getting bounced around during the road trip. Then if the welding shop doing the final welding is just blasting it together sitting on the floor, it's not going to end up as straight/square as it would be if welded together in a chassis jig.

The "right place" for small MIG tacks that will be gone over with a TIG will depend on who will be doing the final TIG welding, not everyone has the exact same TIG welding style & preferences. If you know the guy that will be doing the final TIG pass, always ask him where he wants you to put them.

DILLIGASDAVE wrote:

bbf-falcon wrote:I have a ? for you tiggers. If you are building a chassis or whatever.Can you spot it together w/mig and then take it to the TIG shop?

It's not the best idea but it can be done on both ms & 'moly if you put the tacks in the right place, and don't make them too big. Only problem is if you tack a chassis together, then haul it somewhere, there is no guarantee that all the tubes will still be in exactly the same place after getting bounced around during the road trip. Then if the welding shop doing the final welding is just blasting it together sitting on the floor, it's not going to end up as straight/square as it would be if welded together in a chassis jig.

The "right place" for small MIG tacks that will be gone over with a TIG will depend on who will be doing the final TIG welding, not everyone has the exact same TIG welding style & preferences. If you know the guy that will be doing the final TIG pass, always ask him where he wants you to put them.

Dayum...Dave seems to be like a camode, he really knows his sh!t .

GT300TD wrote:

Dayum...Dave seems to be like a camode, he really knows his sh!t .

Yea mind like a steel trap.....that sometimes snaps shut killing a bunch of my few remaining brain cells.

rmcomprandy wrote:........MILD steel encompasses a lot of territory.......

Boy ain't that the truth.

Mild steel tubing can start out as either hot rolled strip or cold rolled strip, it can be heated up before being drawn into a tubular shape or drawn into shape cold, after the seam is welded it's external weld crown might be knocked down by either milling, grinding, or shaving the seam. The tubing might be normalized/annealed in an oven during the manufacturing process or done at the end (or not done at all). Then some of it might also go through the mandrel process to tighten up the OD & wall thickness tolerances and make the weld seam invisible inside & out to create DOM tubing. And some of it might get heat treated & oil quenched to make it harder/less ductile.

That's probably why the SFI specs for what is accepted as "mild steel" cover so many different types of tube manufacturing processes. They really don't care too much about how it's manufactured as long as it meets ASTM A519 or A513 requirements.