Back deck for window licker short bus

[Tango]

One non-scientific rule of thumb is that frame welding is "probably OK" as long as it is NOT between the axles.

[crashmonster]

If the welding is done right, good but not over penetration and no massive long welds, which should allow the frame to have a little flex, it should be fine.
Back when I was a younger man, in the north east, they made cars and trucks with real frames, not the newer unibodies. If the frame got damaged, you could get a "state certified" welder to repair it. I've seen some ugly repairs, but they held up fine.

OK, my opinion is over.

[ol trunt]

An aspect of this frame welding business has been overlooked. While it is agreeable to weld mild steel frames (given competent welding), welding high alloy steel frames is not recommended as the heat cooks out the alloy mix and leads to early stress fatigue. To be on the safe side consult the mfg of your rig and follow their advice. As a tutorial, the site www.gmupfitter.com (and others) will provide a whole lot of interesting info regarding frame modification.
Jack