Mig and really thin sheet metal,

Its been a while since I have put some thing up about Mig and since my son rolled up today with the muffler of the 2 stroke chook chaser, that he got cheap ( yeah!) I got to use the mig for the first time since it was repaired.


Naturally the part was holed in the most inaccessible place on the inner sweep of a reverse bend, rust hanging off it in leaves and it had been ridden in the salt water. Just to make it interesting it also covered in unburned 2 stroke oil where it not rusted.

Don’t ya just love a challenge.

The first order of business was to get if ground up to shiny clean state . Looking down the bore through the flange I could see pinholes of light everywhere as well as the major hole ,Parallel to the folded seam and about 40 x 12.

Just welding on the sheet thickness was to invite yet more holes.
My plan was to run consecutive stringer beads out from the outwardly folded seam edges.
By doing this it is possible to fill a hole/gap. The technique is not to point the wire square to the sheet , but parallel to it let the heat build up be absorbed by the volume of beads. One has to remember to allow for cool down after each pass.

The other part of the technique is to allow lots of stick out to take more heat out the arc.

Rather than push my luck using this technique for the pinhole areas smack bang in the bend radius I opted to cover them with a patch which I cut from a bit of old car panel. Once again I used the parallel to the surface technique

The wire speed was 2.8m/m and voltage 19 meaning it was headed towards globular mode just starting to sputter and hiss. Wire used was .6mm

Dummy did not think to take a picture before starting work did he ?.

Let the questions begin.

Lets use your problems and hopefully solve them by adjusting or resetting your variable's.

Grahame