General rule of thumb is one amp per thou of thickness, less for an outside corner joint, more for an inside corner. Thin material is much less forgiving than thick so be mindful how much heat you’re putting into the joint. Once you get it a little too hot it will melt the steel back and surface tension will cause it to pull away leaving a hole that can be tricky to fill. Practice on scrap first.
How To Welding questions.
- Thread starter Storm W
- Start date
Basically as low as you can get the machine to give an arc. Use an aluminum or copper backing block. Use as small tungsten as you can. Make the point at least 3 to 1 and use a fine grit to polish the point. Use a E-3 tungsten and if you can't try lanthanum. Use something as a starting block. If you have a foot control just see how small of arc you can hold. Use a rest because at that amperage you will nearly be touching the steel. You need a thin fine point because it has to be at temperature to arc. Hollow grinding can help. If you are using filler, work your arc on to the filler and then pull the puddle back to your work. If you have a foot control you can pulse it or you can set the machine to pulse for you. If it's an older machine set the pulse slow so that it's a comfortable and use one pulse per puddle. If you have high speed pulse you are in luck. You want to set a pulse spike at a level where you have a comfortable arc. Since you are doing thin stuff you probably want to go around 50amps or less. Then you set a background current much lower and timed for a longer time. Turn the high speed pulse up and it will focus the arc. High speed pulse is hundreds if not thousands of of pulses per seconds. Don't be afraid to get some reading glasses or a magnified lense (Cheaters) and then have at it. You will probably have to practice a bit
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- Sep 21, 2014
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Thanks Storm. I'll let you know how it goes when I try it next.
I got closer the next morning when it was cooler and I wasn't dripping sweat into my eyes. I was as low as I could go, 10A and I turned down the Ar to about 2cfm because it seemed like the gas was blowing the arc around(?) But I gave up and just carefully put the individual pieces in the can and was careful when pouring in the powder. That worked pretty well, but I'd like to not have to worry about it.
The things I'll change next time: 1) get better clamping/holding of the pieces so I can focus on the torch, and 2) grind a narrower taper with fine grit. Already learned that I need and to use cheaters.
I got closer the next morning when it was cooler and I wasn't dripping sweat into my eyes. I was as low as I could go, 10A and I turned down the Ar to about 2cfm because it seemed like the gas was blowing the arc around(?) But I gave up and just carefully put the individual pieces in the can and was careful when pouring in the powder. That worked pretty well, but I'd like to not have to worry about it.
The things I'll change next time: 1) get better clamping/holding of the pieces so I can focus on the torch, and 2) grind a narrower taper with fine grit. Already learned that I need and to use cheaters.
Are you using a backer for the weld? Just dump your heat onto that. You can add some filler and make a droplet. The drop is thicker and will handle more heat. Put the two plates on a table and put a small drop of water in between. Use a toothpick to make it wet both plates. It's good practice to understand surface tension. Once it is melted dealing with surface tension is your big worry.