Tried using a welder to patch a rust hole on my truck frame... almost burned the whole thing down

I had this rust spot on my Chevy Silverado frame near the rear axle, maybe 4 inches long. Figured I could just weld a plate over it and be done in an afternoon. Bought a $60 flux core welder from Harbor Freight and watched a couple YouTube videos. First mistake was not cleaning all the grease and undercoating off first. When I struck the arc, the undercoating caught fire and started dripping flames down the frame. I panicked and tried to beat it out with a rag, which just spread it. Had to grab the garden hose and spray the whole underside of the truck. Took me 3 tries to get a decent bead after that and the weld cracked on the test drive anyway. The lesson was you gotta prep way more than you think and never trust a cheap welder for frame work. Anyone else tried frame repair with a budget rig and regretted it?

2 comments

2 Comments

shane_williams42d ago

Wait, did you grind the frame down to bare metal before you started? I've been welding for years and that undercoating is basically a fire starter. You gotta hit that area with a wire wheel on a grinder until it's shiny, then hit it with some acetone or brake cleaner right before you weld. And honestly, flux core on a frame is asking for trouble. That cheap wire just pops and spatters, you get no real penetration. I'd rather drill holes and bolt a plate on with some grade 8 hardware than trust a Harbor Freight special on something that keeps my truck together.

ryan9522d ago

I get what you're saying @shane_williams4, but I've had pretty good luck with flux core on frames if you turn the heat up and move slow. Those Harbor Freight welding carts don't work great out of the box, but I swapped the liner and tips and ran 0.030 wire and it actually lays down a decent bead. Grinding to bare metal is a must I agree, but I'll take a properly tuned flux core over bolting a plate on any day. Bolts can work loose and then you're chasing cracks anyway.