I am looking for reference material written in plain English which will permit me to fabricate a small resistance welder to connect electrical heating elements to buss bars and leads as they are done during mass production, but on an individual basis in repair of various makes and model appliances. My level of understanding drops suddenly after establishing that heat, from resistance at the joint, causes the weld. Power requirements (yea many volts at yea many amps per so much wire diameter) is basically what I am looking for in hopes of adapting one of several power supplies on hand to the task. As a member of the AWS I have not yet found what I was looking for in their literature and hope someone may be of help. I will be welding resistance wire (around 1/16 inch, rarely 3/16") to: stainless steel, steel, and nickel steel (I think) used in high heat eyelit and spade type crimp-on connectors. The jaws of the device will be built to the size of a normal pair of needle-nose pliers to get into confined places in various heating appliances.

Thank you in advance.

-- John DeSantis (partsking2@cs.com), December 18, 2000

Answers

Response to Resistance welder design & theory of opration

Hello,

While I am not prepared to give you the specifics of the number of volts/amps needed, I can clarify one point.

Resistance welding is forging of metal. The HEAT comes from the resistance of the electricity going through the piece, and another important component is the FORCE, which pushes the pieces to be welded together. The final important variable is the TIME that you do the weld for.

You may find the following article of interest: "Setting the Squeeze on Resistance Welding" by Dr Philip J Blakeley. It can be found at: http://www.diverse.dial.pipex.com/layer2/squapr.htm

I would suggest that it may be simpler and lest costly to buy a small used welder that you know will serve your purpose rather than reinventing the wheel . . .

-- Sam (snowsam@eng.auburn.edu), December 19, 2000.

The previous answer is correct. You'll need lots of Amps, a few volts (~4-15V), and force control on a small part (1/16) will be important. If you send me your address, I'll forward you a small publication, "Fundamentals of Resistance Welding", it's sorta written in plain english. :0) Good Luck. Kurt Tolliver kurt@unitekequipment.com btw, if you look on eBay, very often used resistance welders are listed at very reasonable prices.

-- Kurt Tolliver (kurt@unitekequipment.com), December 19, 2000.