Thin sheet metal welding tips

[Rob Taylor]

I have tried a few different things with limited success welding thin sheet metal.

I have a roll of 0.8 mm mig wire that I have been trying to use as filler wire.

Setting the torch on level one of Mode 1.

It is a but weld that I have been attempting.

I am guessing the galvanized sheet is about guage 19 or 20 (It seems to be about 1mm thick before grinding).

I have ground off the zink coating on the metal in the area of the weld (I read that zink interferes with the weld).

My problem is that as soon as the sheet reaches melting point I seem to have a hole in it. The mig wire I am using
for filler seems to take more heat to melt than the sheet metal.

Things I have tried is to put a piece of 1/8 inch steel strap against the back of it, use a cutting nozzle instead of a welding
nozzle, try level one on both Mode 1 and 2 (blows holes much faster), and attempt a soldering technique using the mig wire
by placing the wire in the torch flame and gobbing it onto the red hot sheet metal (looks terrible and ends up with pin holes
all through the partly melted gob of mig wire).

I am thinking that I may have to give up and braze the joins and / or overlap the tin at the joints.

Any ideas or tips?

Thanks,
Rob

[Adam Figueroa]

Good Morning Rob

         I have a some info that will help you with your thin sheet metal. Remove the ground clamp and put your filler rod holder to the front of the multiplaz it will act as your ground. It will take the place of your ground when you put the rod to the work piece. This helps with not putting too much heat into the sheet metal. You will strike your arc on your filler rod. Try using a 1/8 ER70S-2 Mild steel rod. I like to use thicker rod then my work piece. Try these settings 50% isopropyl alcohol welding nozzle make sure it is clean inside and out. mode 1 setting at 1 mode 2 setting at 1 or 2 keep torch at 150V. If you need a tighter arc you can shape your cathode like a sharp pencil. Let me know if this help out.

   

Thanks Adam 

[Rob Taylor]

Thank you Adam,
That is almost "out of the box" thinking. I hadn't even considered swapping around how things were connected but now that you say it there is a lot of sense to it.
I will try it as soon as I get a chance and report back how it worked out for me.
Take Care,
Rob

[Rob Taylor]

I tried this idea on Thursday night and it did work surprisingly well.
Thanks,
Rob

[Adam Figueroa]

Good to hear it worked out. Was wondering if you could snap some pictures of your work.

Thanks 

Adam

[Rob Taylor]

Hi Adam,
I had intended to practice a bit more first before displaying any photos of the results of using this technique but... here is
a test piece that I did and after grinding off the weld so I could examine how much penetration I may have had on the base metal.

[Andy Stack]

I've welded some thin stuff with my Multiplaz. I weld 16 gauge all the time with no burnthroughs and I've welded as thin as a mason jar lid successfully. What works for me is Setting the welder on 2/4. I don't have luck with it on 1 because it seems like it won't hold an arc with any amount of stability. So I use 2/4, I like the right on 4 because it gives me the ability to make the arc a little longer for tight areas. I interpret the right number as basically arc strength, so the higher the number, the longer arc you should be able to achieve. And I try to set the voltage between 170 and 190. Once my torch is stable, I begin welding. If it's really thin, I use a rod big enough that I can start the arc on the rod (when I'm welding really thin metal, I'll put the end of the rod where I want the puddle and initiate my arc on the rod itself, up just a touch from the end so that I melt the rod and use that molten bead to melt into the thin metal without adding a bunch of excess heat. I do quick jabs in, get an arc and puddle, always looking for puddle tie-in all the way around and continue that through the weld. It comes out looking pretty nice. if you take the time to stack beads real close, it can look much like a nice tig bead. But it's not always easy to get pretty beads. 

Also, I tossed away the filler rod ground a long time ago and have never had a single issue. It was cumbersome and I never liked welding with the plaz until I tossed it. And the fuel I've been using, which I'm pretty happy with, is wood alcohol, also called denatured alcohol. I buy it in a 1 gallon tin and it's cheaper than what I was using before, which was 91 percent isopropyl alcohol. I've also done a mix of the two when I first started using the wood alcohol. What are other's thoughts about fuel and the filler rod ground?

[Rob Taylor]

Hi Andy,
Thanks for the tips.
I think that the wood alcohol is generally not recommended due to the fumes it generates are not safe.
Take Care,
Rob