TIG Welding Questions ~ Small Diameter Round Stock

Date 03-04-2008 16:03

I'm building some storage racks, tool box racks, tool guards and other assorted widgets in the shop using 5/32" diameter stainless round stock. I have been fusion welding the T connections with DC TIG using 1/16" tungsten. The machine is a Miller Maxstar 150. Its hard to add filler to these little welds because of their size and brief welding time. (well, hard for me...)

I stumbled onto 2 packages (Qty of 20) of .040 tungsten and a torch part kit, so wanted to do some experimentation. Would I benefit from using these when welding the small round stock? What applications use this size tungsten, and what are the amp settings I should work with? I do have some .030 and .045 stainless MIG wire I could use for filler.

Thanks for any tips

~thirdeye~

By bozaktwo1 (***)

Date 03-04-2008 18:08

In my opinion, just fuse it together. Adding filler cools it down so much at that low amperage that you may do more harm than good.

By aevald

Date 03-04-2008 19:20

Hello thirdeye, if you are having difficulty avoiding undercut or burning the two pieces back when you are trying to fuse them together you may want to try a couple of things. First off try to get the pieces to fit together tightly, using some form of a clamp or other sort of holding fixture might be necessary. When you go to start the arc keep the tip of the tungsten in pretty close to the weld area, don't hesitate to give it a pretty good burst of pedal to get the two pieces to bridge to one another. Many times while people are trying to be careful and slowly bring up the heat they may actually cause the two pieces to ball and melt away from one another. Another method you could try would be placing your filler rod at the juncture where the two rods come together, then while holding the filler in this spot hit it with a burst of heat and withdraw the filler at the same time that you back-off of the pedal, be sure to keep the shielding gas on the weld area while it is cooling. A few more thoughts for your consideration. Best regards, Allan

By thirdeye (***)

Date 03-05-2008 03:13

Allan,

No filler on the right, filler on the left.

I'm not really getting undercut, more like a wash with a reduction of thickness...which is typical of tacking, and is what I sort of expected. I did get some burn back and serious deforming due to the heat on some of the sample welds. I am using a tight fit and have a simple jig that works for most of the connections. I also tried pre-placing the filler. It sounds like playing with different methods using the pedal is in order.

Back to one of my questions, what amp range should I be working with.

By Superflux (****)

Date 03-05-2008 04:16

MIG wire is an excellent source of "micro-filler wire" for tig. Also, Insulators tie wire is a good stainless filler. Hobby, hardware and auto parts stores also carry spools of small diameter wire that can be used for filler. The previous response was right on about the balling up problem.... with your Maxstar ....since you have a jig to hold the parts, disconnect the thumb wheel and use your other hand to give it the burst and quick cool. I personnaly am unable to use the torch mounted amp controls for fine, tedious work unless d/c'ed as mentioned above. Another option is, my local welding supplier had a sample spool of Silicon-bronze 0.035 mig wire he gave to me cuz it had been on the shelf since biblical times. I used this wire for all sorts of "TIG-brazing" projects like your wire assembly where excess heat is a concern.

Hope this helps

By aevald

Date 03-05-2008 04:54

Hello again thirdeye, Superfluxe's last suggestion might really be the ticket, using the silicon bronze will yield a joint with plenty of strength and avoid much of the heat issue you are seeing with the welding. In reference to the amperage you may need to perform the welds, I am going to suggest something around 30 to 45 amps or so. If you go the route of the silicon bronze you may even be able to reduce this further, I believe 1/16" tungsten should work really well whether you are welding or using the silicon bronze. If you go with the silicon bronze you should be able to start the arc and before you see a puddle form or notice any melting of the base materials you should be able to apply the bronze almost the same as when you are torch brazing. Give it a shot and let us know how it goes. Regards, Allan