welding advice on motor mounts Tig

Hi,

I am going to weld two different thickness mild steel together. One is 1/8" and the other is 3/16"

What I am doing is welding in some motor mounts in my 30 Model A, with a V8 flatty.

The motor mount is 3/16" and the frame is 1/8".

I have a Lincoln Precision Tig 275.

What I am asking is what size tungsten should I use, 3/32" red 2% thoriated, what amp setting would I use, and what postflow?

I am going to tack the motor mounts in first to make sure everthing lines up then going to weld them in on the top and bottom sides.

Please give me any tips and advice before starting this endeavor.

Thank you in advance


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The 3/32 tungsten is ok. I have my post flow at 5 seconds.
I have a heat control on my torch and for that job would set the machine knob about 100 amps. With a fixed heat control try starting at 90 amps. Practice on some scrap first.
I would use 3/32 ER70S rod.

 

3/32 is fine.
rule of thumb (to get you started) is 1 amp per thousands.
so 125 amps should be about right

 

I usually set the amperage at max and use the pedal to find the sweet spot. Doing practice welds is the best advice you can get. try and keep the heat on the thicker steel and move it to the thinner piece. It will take a bit of practice to find the best balance of how much time to spend on either side of the weld to get good penetration on both pieces.

 

I just did something like this TIG'ing 1/4" to some 1/8". I did it without any filler rod by concentrating my heat on the 1/4" to use the extra thickness as my filler onto the smaller. Came out looking pretty good. 3/32 with 125 amps available on the pedal.

 

36tbird,

So you got away with using no filler, just fusion welded.

 

times 2.