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

Standard spot welder with suitable tips is the way all the racks and grocery carts are put together. The tips for this application are either large flats or flat on one side and grooved on the other.Not sure about the kw requirement for various wire sizes. I've been meaning to do some quick testing using the 120 volt portable unit out in the lab. Suspect that it will do 1/8" steel wire, not much more. And that 1/4" rod would take a 10kw unit.

The current at the tips is in the 4000 amp range (yep 3 zeros on that one!) for a small portable unit. Goes up from there on the big industrial units. Voltage is on the the order of 1 volt total in the system. Takes some big cables to keep the voltage drop under control if you separate the transformer from the tips. That said, take a look at the robot spot welder videos from an auto assembly line.

DIY resistance welding?

Apr 12, 2010 25 Replies

Rate this thread:

Joe Pfeiffer 16 years ago

"have to" is a strong word. But you've got to pump a *lot* of current, and long cables will get both very heavy and very expensive very quickly.

Vote

RoyJ 16 years ago

Vote

David Billington 16 years ago

I just stuck together 2 crossed pieces of 6mm rod. They were stuck fairly well but I did get the weld area to fail when I held one in a vise and twisted the other to try and align the pieces, probably do for a spice rack though. That may have been an issue with the material which was I think EN16T which I had to hand. I'll try and redo the test with some mild steel and round and square for interest sake and post back. The spot welder is a 240V handheld unit, spec plate says 2kVA conventional, 11kVA welding , 7000A.

Vote

dan 16 years ago

What's that Lassie? You say that Steve B fell down the old sci.engr.joining.welding mine and will die if we don't mount a rescue by Mon, 12 Apr 2010 21:07:04 -0700:

What ???

That is what we are discussing.

Vote

Martin H. Eastburn 16 years ago

In college we had (late 60's) an RF or radio frequency driven spot welder. The hole unit could fit in a suit case - ours on the top of a 24" x 24" lab table.

We used it to spot sheet metal for various jigs and projects. The many many many strand wire was over an inch in diameter. It was a foot feed clamp on it - so you could hold two parts with hands.

Mart> steamer writes:

Vote

Martin H. Eastburn 16 years ago

Remember the metal inside and out should be clean - to lower resistance and allow positive weld in a spot.

Mart> Steve B wrote:

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