Fusing Wire questions

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I have long been curious how they fuse or weld solid wire such as 1/8" together with little to zero visable HAZ and no filler. I am talking about the type of wire items that can be found in kitchen plate racks, bathroom toothbrush holders, and the like. Seems like the wire is fused together but how is it done? It almost looks like it was superglued together. Any ideas?
Reply:Spot welded.
Reply:Probably a special machine called a "Butt-Welder".....The two ends are squared off, cleaned and prepared.....They are then clamped in two clamps that hold them aligned and apply pressure against each other.....Electrical current is passed through this junction briefly while constant pressure is applied.....The ends fuse together.....The weld may or my not need grinding to clean it up afterward.....Patrick
Reply:Same way they weld band saw blades togather.DewayneDixieland WeldingMM350PLincoln 100Some torchesOther misc. tools
Reply:Sorry for my ignorance but how do they weld bandsaw blades together? I assume they pass high current through the contact point to fuse the ends together. If they spot weld the wires together I guess they ground one mating side of the assembly and then mechanically place the items together. The then zap the other half of the wires with the outcome of mechanically fuse parts? The junctions are extremely clean and quite solid. I would like to replicate these types of fusions at home. How would one go about doing this? What hardware would allow me to do this? Tigging each and every junction is at times not possible or too tedious.
Reply:Band saw blades are brazed.
Reply:Or welded, depending upon the equipment available.Yellow, are you talking about butt joints or welds at the crossover points of wires in shelves and racks?  In either case, however, they are resistance welded.  The two wires to be welded are squeezed together mechanically, then a fairly high current is passed through the point of contact for a pre-programmed period of time, which may be a fraction of a second.The squeeze pressure, the squeeze pressure/time profile (which may be as simple as a spring that maintains the desired squeeze force as the metal flows), the current, the time, and often the time/current profile, are all tightly controlled to achieve the quality of welds that you have seen.You'd be hard-pressed to reproduce the welds you see in kitchen products on a consistent basis in a home shop in the absence of a spot welder, but if you just want to join wires to create an object that pleases yourself, you can do it at home manually using a low-voltage, high-current transformer (perhaps 1 or 2 volts at 100 or 200 amps, depending upon actual wire size and alloy). I've done decent repairs on wire-form objects using an 800 Watt low voltage transformer with a handpiece that holds a stubby, fat carbon.  The main problem was too much heat too fast to control easily.  But it worked!  You can do the same thing (probably with less melting and spatter) without the carbon.   You have to work out all the parameters for your specific product and materials and power source.Check out information available from the Resistance Welding manufacturer's Association ( http://www.aws.org/rwma/publications.html)awright
Reply:Originally Posted by 76GMC1500Band saw blades are brazed.
Reply:awright, That's exactly the info I was looking for! You sure do know your stuff. I was referring to the crossover points in the wire items exactly like in shelving. I am interested in what purpose the carbon block serves. I guess I would need a suitable transformer and a soild enough momentary switch to control the pulse. The only spot welders I have experience with are the ones for dent pulling where the electrode remains attached to the body panel for pulling on. Although I am fully capable of building timing circuits I think that would be overkill for my intent and purpose. Do you not think I would be doing harm to my power supply and/or transformer by shorting it out over the contact joint, even thought its only for milliseconds? I'm really interested in seeing or reading more about your homemade spot welder. littlefuzz. I've used a similar bandsaw blade welder once before. If I remembered correctly is was just like spot welding. A breif zap was all it took. Never heard of the brazing technique.
Reply:the brazing method uses silver solder and can be done at home without a lot of fuss, how it compares to welding I am not sure, but I think that it works pretty well.
Reply:Bandsaw blade brazing is done with a torch and standard brazing technique.  A scarf joint (tapered overlap instead of butt) is used to increase the area of the joint and make a gradual transition of load across the joint.  The nice thing is that you can form a band this way with just a grinder, torch, flux, silver solder and a homemade device to clamp the blade ends in alignment as you braze.  Equipment cost about $15.I didn't want to give the impression that I had built a spot welder (although I might try it someday).  What I was trying to say was that I used a carbon "burner" that I had on hand to effect some repairs on a wire frame object (a basket that holds out the filter bag in a shop vac to prevent the bag from getting sucked in against the final filter element).Rather than repeat myself, you can find comments on carbon torches by me and others by doing a search of this site on "carbon torch.  There were two or three threads on the topic.  "http://www.weldingweb.com/vbb/showthread.php?t=6529&highlight=carbon+torch  There were two or three different threads on the topic.Actually, now that I think of it, I did build a 50 Joule capacitor discharge spot welder several decades ago.   It was to weld strain gauges onto railroad rail to measure rail bending..  Worked fine.                                      I'm having trouble staying awake just now so I'll cut this short.  I'll try to come back to answer some of your questions.awright