Joining Two Round Wires

Years ago I made quite a few gaskets by butt welding the ends of 18 ga OFHC copper wire together to make a ring for a UHV flange that I had to R&R several times a week for a few weeks, and we couldn't afford to buy new gaskets :-). I made a little V fixture so I could clamp the wire with the ends butted together. I cut the the ends with pliers a little long and then filed them square by eye. For SS I would really want one of those tiny wet chop saws like those sold for tiles or whatever. I used a natural gas/oxygen micro torch with the smallest tip we had, because that was hot enough and we didn't have acetylene. Get a tiny molten pool just to one side of the seam (say one wire diameter away) and walk it to the other side, then let it cool. Flip it over and make another pass opposite the first, then usually two more passes at 90 degrees to the first. Heat control was everything because too much and it melted through and I had to start over :-). A little pressure pushing the ends together would let the joint kind of bulge out just a smidge, and I would sand it back to a uniform diameter. Without the pressure sometimes the joint would be undersized and I was afraid it wouldn't seal when crushed in the vacuum joint. I wanted to anneal the wire and didn't have an oven or hotplate I could take that hot, so the last step was to back the torch off and heat the wire until it was almost dull red, then move the hot spot around the ring so the entire length got to the same max temp, then drop it into a beaker of water (just to cool it faster, the quench didn't do anything for the annealing).

Anyway, for your SS wire I would try the same with the smallest TIG torch and tip I could find, with argon, starting at minimal current. The goal is a puddle width about one fourth the wire diameter or a tick bigger, then walk that across the seam. That assumes a puddle depth about the same as the width, so you are getting at most 50% penetration on each pass. Trust me, if you aim for that you will get more and will get a nearly full strength final weld, but if you try for 75% penetration you will just blow right through :-). For a tee joint grind or file a vee into the end of the sidearm wire to get the best fitup you can. For the side-by-side I guess either file the sides flat or maybe lay a small diameter piece of filler wire into the groove and then flow that into each main wire, depending on which appearance you like best.

If you need to do lots and lots of these in SS, try making up a clamp fixture where each clamp is electrically isolated from the other and the clamp leaves maybe a wire diameter stuck out into space, butt the two ends together with some reproducible force, and either use a real spot welder with precision timing or use stick cables on your TIG and mash the pedal and count "one mississippi, two mississippi", then get off. Rig up a hose of argon shield gas to keep down the corrosion. My complete swag is that for

1/16" 316L wire you will only need 20-40 amps. I bet you could even do rings bigger than some minimum size so the resistance around the long way is high enough to keep it from getting hot enough to melt while you make the butt weld.

Well, those are my amateur suggestions, worth what you paid for them :-).

----- Regards, Carl Ijames "Bob La Londe" wrote in message news: snipped-for-privacy@googlegroups.com...

In another group I read joining two round pieces of stainless wire often comes up in conversation. End to end, side by side, and end to side are all done or desired from time to time. The wire sizes range from 0.03" to 0.06" give or take. I would be curious what approach some of you guys might take to do these processes quickly and efficiently.

Mostly the join would be of the simae size wire to itself, but occassionally it might be joining a lighter wire to a heavier wire. The resulting joint needs to be corrosion resistant, but not to an extreme. It is not exposed to strong acids. Hard or saltwater at worst. Life in use does not need to be infinite, but over a lifetime it might see several hundred hours of immersion with thousands of dunking cycles.

If the resulting joint is 75% as strong as the original wire or better that would probably be satisfactory. The wire is most likely a 308-316 spring wire, but others might be used.

The exact application is not really important. Its not a secret, but I often find that when you express an application people begin to critique the why and how of the end, rather than focus on the now problem. If you know or guess the application please keep it to yourself until the specific task has been thought about for atleast a few days. Its not a secret. I just would like to see some pure thought on specific process ideas first. If nobody has blurted it out I will be glad to share in a few days.

Bob

I recently was helping out a friend by doing some TIG welding of Stainless Flex hoses. My friend is the head welder at American Flex. When I taught at the Divers Institute they were my neighbors, and we did a lot of back door barter between the shops. They weld up custom flex hoses of all sizes and lengths for hydraulics, diesel exhaust and various other applications. I would often weld stuff for them when my friend was out of town or sick. It is tricky work, but I find it kind of restful and relaxing. Like raking sand in a Zen rock garden. They recently fired his assistant weld so he was getting buried in custom orders. The welding is all done on rotators. The ones with stainless braid on the outside are the trickiest because you have to weld the outer collar, the braid and the flex hose together first, then weld your fitting to the end. To make it a little more fun I use the "never-ending filler rod" trick. As the filler rod gets down to a few inches long, I butt weld the next filler rod to the back end. The trick is to touch the ends, bring up the TIG arc very gently until the ends start to melt, and then push them together a tiny bit so you get a little bead joining them. The hard part is that you can't have any side movement while the ends are molten, so you have to be very very still for a few seconds.

Welding dissimilar wire diameters is harder, but just requires good heat management. Keep the majority of the heat on the larger wire.

In article , Bob La Londe wrote: