Mig Welding thin Lap Joints

I am going thru all the joints using mig welding and tig welding.

Corner, Lap, Edge, Butt, Tee.

I covered Corner joints recently using that little project of making a die.

I called it a dice. But Helpy Helperton on YouTube corrected me and let me know that dice is plural for die.

(I actually knew that die was technically correct, but I figured the word "die" would be understood by less folks, so I just said dice)

So..This week, its time for lap joints. In the next few weeks , I am going to be bouncing back and forth between tig and mig but for this weeks video its mig again.

I kinda intended to focus on 11 ga , (3.17mm) thick cold rolled steel but I wanted to make things more interesting so I also got some 16 ga thick exhaust pipe fittings from Auto-Zone because exhaust pipe and mufflers are such a common mig welding job.

You know what I mean...If you have a small mig, and your friends and neighbors know it, you are likely to get asked for a "small favor" every now and then.

Heck, exhaust pipes are just the kinda thing that got me started buying my own welding equipment. I figured instead of paying over 300 dollars for an exhaust assembly when all it needed was a muffler, I would just buy some gas bottles and gas weld a new muffler on. ( i already had a torch kit lying around).

Then, a friend gave me a JC Penney buzz box... Then I horse traded for a rectifier and high freq box,... then I bought a syncrowave 250,... and on and on it goes.


So anyway, back to mig welding lap joints.

Lap joints are commonly used to patch things. Like when a hole is worn in a blast cabinet, a common repair method would be to cut out a doubler patch, and weld it over the hole to get the blaster up and running again.

Another common application for lap joints is a rack made from angle iron. After all the shelfs are framed up, they are usually welded to the uprights using lap joints.

But another common lap joint is exhaust pipe welds. When one pipe slips over another to make a joint, thats a lap.

All the welding done in this video was done with .030" er70s6 wire and 75/25 ar/co2 gas set at 15cfh.


For the 11 ga lap joints in this video, I settled on 18 volts and around 210 inches per minute of wire speed.

for the thin stuff, the 16 ga exhaust pipe, I adjusted things downward to 16.5 volts and around 170 ipm.

For the 11 ga, I kept a short stickout but for the 16 ga , I pulled back the stickout not only to help me see things better and to be able to film the welding, but a longer stickout is ok and even better for thin sheet metal,...less likely to burn thru.

See more mig welding videos