TIG "Cold" welding

[Toymaker]

After watching several videos on the subject of "cold welding", I decided to give it a go for myself and purchased a TIG machine with a "Cold" setting. For those that don't already know, cold welding produces far less heat in the parts being welded, BUT, the electric arc at the tungsten tip still carries enough current to melt the base metals, so the welded section is not actually "cold". The reason this process is termed "cold" is because the electric pulse that melts the metal is only a few milliseconds in duration resulting in far less heat being generated in the overall parts, thereby preventing parts from heat-warping.

I'm NOT a proficient welder, my aluminum TIG welds are truly ugly,...but the photo below shows my Cold weld of two pieces of 3mm 304 stainless using no filler wire, and with a 200 Amp setting. As a size reference, the two drilled holes are 3.3mm diameter, and the two 304 pieces are at nearly 90 degrees.

 

[timo_gross]

Interesting subject. The penetration is as far as I understand not so good, so this is not a replacement for structural welds. Not the new solution:
"Boiler repair for beginners "
How does it compare to welding "normal" without filler?

I could try a few minutes with a PUK Welder by Lampert. That machine works (I think) similar. It is suitable for watch making and other tiny things.

The most fun is the Welding microscope. You can look at the work in "Daylight" and for the split second when the arc strikes, the shutter goes dark.

 

[Toymaker]

I agree that cold welding is not a replacement for traditional TIG, but it might be better suited for the model world.

One of the reasons I started this thread on cold welding is because I believe this type of welding could be very useful in the model world, where metal thickness is typically quite thin, and the welds produced are also relatively small. The width of the weld in the photo I posted is only 2mm,...I don't know how deep the penetration is.

I think cold welding should also work well on most any structure using thin-wall tubing, where too much penetration results in burn-thru.

 

[ninefinger]

I'm not sure sure of calling it "cold" welding as that term has another meaning - the welding of 2 similar (identical?) metals that are perfectly clean to one another - usually with some light to heavy pressure, they self weld without added heat (therefore cold welding).
I think what you are doing is commonly called pulse welding. There is a high amperage for some short duration, followed by a low amperage, repeated at a frequency.