Tig or Mig welding Chromoly

[Glasser]

I've heard you can not MIG weld chromoly.
Since I will probably be getting a chromoly roll bar build I am concerned about after I get home will I be able to add things to the cage,I only have a MIG welder, not a TIG welder..... . I started looking on the Internet and found that it is possible to "MIG" weld Chromoly "IF" the proper wire is used.
Here is the thread I found...
http://www.hobartwelders.com/weldtalk/showthread.php?referrerid=6157&t=22910
I'm still unsure about heating the material first.
I also found out while hunting for info you can weld mild steel to chromoly, It was being TIG welded however. This was another concern of mine.......

I would like your input as well.

Also can anyone think of anything else that may be needed to be welded to the chromoly tubes? Seat belt brackets for sure..... If I know what needs to be welded I should be able to be prepared and get it done while the cage is being built. (I'm having a bit of brain freeze thinking about it)

[MURZI]

Just use DOM mild steel. Chromoly has the advantage for weight...not cost or function. You are going to race it are you??? Weight matters then...but i bet the diff would only be about 10 lbs or one less cheeseburger a week for lunch.

To answer your question I would only TIG chromoly.
_________________
62 vert
2276
Tim’s welded heads
45 Dells
A1 sidewinder
Fk44 cam

[Dale M.]

Yes you can MIG Chrome Moly (4130).. Do not try to use center shield wire.... Use solid wire and shield gas... 75% argon 25% C02 is best...

Dale
_________________
“Fear The Government That Wants To Take Your Guns" - Thomas Jefferson.

"Kellison Sand Piper Roadster" For Street & Show.
"Joe Pody Sandrover" Buggy with 2180 for Autocross (Sold)
============================================================
All suggestions and advice are purely my own opinion. You are free to ignore them if you wish ...

[chadzu]

There is no reason why you can't weld 4130 with a mig. The weldor is more important than the welder. Mild welds just fine to 4130

If you really want to stir the pot you need to ask about post welding heat treatment.

[Glasser]

Thanks guys.
I might take it to the secret street local Friday night drags once or twice but nothing serious.
I'm in a bit of a pinch. The guy that is going to do the cage is almost insisting I go chromoly becuse... well I think he likes working with it better......I know he has it in stock (buys it by the truck load) and said he has no problem tiging it all for me. Yes the cost will be more but I think the deal is going to be cheaper than going somewhere else and doing it in DOM so why not go for it. (I'll be doing a lot of the work myself... my request).
If I can weld it with my Mig (I think I already have this mixture of gas) then I'm comfortable doing it Chromoly and there shouldn't be any issues. I just didn't want to back myself in a corner and have to drag my car to a shop for every little thing I wanted to add to it because I needing it tiged.
As for weight he did say it would make a difference only because you can run a thinner wall. But yah how much would it really amount to?

Thanks a bunch guys!!