Chassis build questions

Chrome-moly CAN be mig welded. You have to use the correct filler wire. Thin wall tubing (such as roll cage tubing) doesn't require pre heating so mig welding is ideal. Much faster.

two95s wrote:Chrome-moly CAN be mig welded. You have to use the correct filler wire. Thin wall tubing (such as roll cage tubing) doesn't require pre heating so mig welding is ideal. Much faster.

While it may be physically possible to Mig weld 'moly, it's just not legal to do so in any NHRA/IHRA/ADRL/SFI/etc drag racing specs.

DILLIGASDAVE wrote:

two95s wrote:Chrome-moly CAN be mig welded. You have to use the correct filler wire. Thin wall tubing (such as roll cage tubing) doesn't require pre heating so mig welding is ideal. Much faster.

While it may be physically possible to Mig weld 'moly, it's just not legal to do so in any NHRA/IHRA/ADRL/SFI/etc drag racing specs.

Exactly, it is very easy to do but the powers to be think that it is not safe, so.....it is illegal.

If I go CM it will be done by Madman and they tig everything. If I have to do it myself, it will be MS and I'll use my trusty 220v Miller Mig.

One of our local guys, Barry Wright Race Cars, is one of the top Super Late Model dirt car builders in the country. They MIG every c/m chassis they build. It's just not accepted in drag racing.

I can see where the dirt car stuff probably could get away with Mig welding 'moly since they probably use thicker wall 'moly tubing for a larger amount of their chassis than the thin wall tubing range (.083, .065, .058, & .049) that is used for drag race builds.

For me even if Mig welding 'moly was allowed in drag racing, there is no way in hell I would do it. No matter how good someone's Mig skills might be, they would be hard pressed to lay down consistent/even Mig passes on the thinner .065/.058/.049 'moly tubing without creating either a "too-cold" start, or a "too-hot" finish, since you can't ramp/control the filler wire speed & amperage heat up/down with a Mig in "real time" (as the weld progresses) like you can with Tig welding's hand fed filler rod & foot pedal controller.