James Waldby wrote:

On Mon, 12 Apr 2010 11:50:03 -0500, Pete C. wrote:
Don Foreman wrote:
On Sun, 11 Apr 2010 23:47:01 -0700, "Steve B" ... wrote:

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 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?
...
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.

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

Maybe so, or maybe not, if you refer to items 45689 and 45690 like at
http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=45690.

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.)

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.