DIY resistance welding

Apr 12, 2010 7 Replies

Rate this thread:

Steve B 16 years ago

I want to make some small diameter rod racks for spices. I think I'll use

1/4" or less square and round bar. I'm going to twist the round, and square, making spirals, geometric designs, freehand stuff, then bend it to form the rack. Mainly kitchen spice racks, knife holders, holders for containers, etc.

I have a Lincoln 175 SP+, and can do some HOT spot welds. I don't want to do very much weld metal deposit to keep from warping.

I have been interested in what it takes to put two pieces of bar together, and zap them and melt them like the shopping carts are made. They come up so beautifully fused and even.

Is there a resistance welding device made, or can I do it with just a welding machine with a momentary blast of current? As with CadWelding studs, is there any type of powder available that I can put in the joint that would melt when it arcs?

Or just keep it simple and tack it hot?

Steve

Vote

Don Foreman 16 years ago

Spot welding like that takes well north of 1000 amps.

Several guys have made spot welders out of microwave oven transformers. I haven't done that so I'll defer to someone who has.

Vote

Pete C. 16 years ago

Harbor Freight sells two models of inexpensive spot welders which would probably work adequately for the application.

Vote

James Waldby 16 years ago

...

Maybe so, or maybe not, if you refer to items 45689 and 45690 like at .

HF rates these 1.5KVA units for 1/8" metal, probably referring to the total thickness. I doubt that they will work ok for two pieces of 1/4" bar. (I have the 220V version and have fastened pieces of .1" strap together ok with several spot welds per join, but it was easy to twist apart single welds.)

Miller rates its $5000 20KVA 12500A units at 1/4" total thickness, per but that probably is quite conservative.

IIRC, Gunner has an old floor unit something like those Miller's or a bit bigger, that he might part with at less-than-new prices ...

Vote

Pete C. 16 years ago

Yes, however since the stated application was "spice racks" it would seem that once one started sketching out a design it would be obvious that 1/4" wire would be absurd.

I've been thinking about picking up the 240V HF unit to add to my home shop. I don't have a specific use, but it would seem to be handy for various projects.

Vote

Bob Engelhardt 16 years ago

I would be one of those who have:

formatting link

'Cause I just had to know if it would do Steve's job, I tested it. I used 3/16 rod, because I think 1/4 is just too big for spice racks and that sort of stuff:

formatting link

It took 3 or 4 tries to get the timing right ('bout 3 seconds, I'd say). The joint shown held while the rod bent.

As described in the DropBox writeup, my welder draws 17A at 240v, or

4kVA. 2000A output if one divides the 4kVA by the 2v OCV.

Iggy's 5kVA, $70, welder was a great deal, but it's gone. And it takes floor space - a serious limitation for some of us .

Bob

Vote

Don Foreman 16 years ago

Spot welders create rather strong magnetic fields that can raise hell with pacemakers and ICD's (implanted cardioverter defibrillator). Folks that have such devices should know to stay well clear, but some won't so the operator should know so he can caution others.

Vote

Mark Rand 16 years ago

Don't know if you've already seen this one Don, but it's relevant to you and other ICD/Pacemaker users:-

formatting link

Regards Mark Rand RTFM

Vote

Join the Discussion

Have something to add? Share your thoughts — no account required.

Didn't find your answer?

Ask the community — no account required