Welding Tips and Tricks

Currently we silver solder motor brush leads (stranded copper wire) to the stator bars in motors but this requires a lot of care on heating and the flame path. What I wanted to try was tig welding( or using the tig as a heat source) to braze or weld these leads onto the wire. The factory uses spot welders but a complete teardown is required and I want to avoid that.

Anybody tig copper to copper?

thanks

Jim

Welcome, Jim,

It can be done, and those with copper experience will (sooner or later) comment, but I'm leaning toward the idea of using a TIG power source to compression-spot-weld, because the braid will behave as very fragile under a TIG arc.

How big/wide a braid to how broad/thick a bar? I'm thinking through how I'd attempt/experiment this, and size matters...

Steve S

the braid is about 3/16 in diameter and the bar is about 1/8 thick. It is the field winding which is usually made, at least in large starters, out of 1/8 or so thick by about 1/4 wide. flat wire can carry more amps and is easier to wind in tight coil form. I figured I would press the braid in with some sort of clamp and hit it with the arc using silver solder for a filler when it got hot in the immediate area. that way I have an intense heat source without the side splatter of a flame.

I am going to try this out tomorrow and I will send some results.

Could u over load the wire with solder and then place on the bar and heat?

Drifta-X wrote:Could u over load the wire with solder and then place on the bar and heat?

I don't think that would get enough on it. It may though.
I'll tell you I've had to silver solder new brushes in the starter on my psd, that stuff takes a lot of heat to melt.
The guy I got the brushes/rebuild kit from gave me four little pieces of silver solder. Probably about 1cm^2.
I barely got if after trying many methods.
He had a "pinch" spot welder that they used. (It was a electric motor shop) But these days, those are hard to find.
Really I don't see why it couldn't be done with tig. But very interested to see if it works.

Sent from my SM-G900R4 using Tapatalk

I should probably rephrase the "silver solder" comment as that is high temp stuff the HVAC guys use. I meant to say silver bearing solder which melts about 600 degrees F.

emfrebuilding wrote:I should probably rephrase the "silver solder" comment as that is high temp stuff the HVAC guys use. I meant to say silver bearing solder which melts about 600 degrees F.

Ahh. Different animal entirely. I'd pre-tin the braid, and use a 500W gun and be done. No mess.

Steve S