I tried to tig aluminum the other day and all I got was a strange unstable arc. It would form an arc then cut out then form an arc then cut out, on, off, on off. Also the tungsten didn't ball up like it should. I was using AC setting, pure tungsten (green rod) and 100% argon gas. I have high frequency start. The aluminum was brushed with SS wire brush before attempting to lay a bead. There wasn't even a puddle and the filler rod didn't wet onto the base metal. Any ideas what happened? Or what settings I can try change? I use DC for steel/bronze just fine, and have one small aluminum thing to repair for a friend.
need to know what machine you have to be any help, sounds like you accidentally flipped a switch or spun a dial. on the stupid high end machines I occasionally use, I take a picture of the Panel and note what I'm welding, so I can go Back to it easily... Much better then reading the manual for an hour to realize someone flipped a glide slope or start stop switch Ect. V/r HT1
Kinda sounds like the collet holder is not tight to the torch causing it to arc from the copper to the metal to be welded. Double check that the collet is tight to the torch body before inserting the tungsten and that the tungsten is clean so your getting a good connection in the collet. Double check your ground as well... If your welding thick aluminum make sure you pre heat it!!
For Tig on aluminum using AC you need to use continuous high frequency not just start. A 250 amp machine is a little light for aluminum. Even with a 400 amp machine I often preheated to the temperature melts solder when you touch it to the aluminum.
I can only use 30 amps from the wall because that's my power line capacity. But even with that power I should still be able to maintain an arc though right? I can try preheating when I get home. Maybe I'll film it and show you what's happening. Might help clarify. The tungsten was tight because I welded bronze right after without an issue. But I can recheck it to be sure.
If you are plugged into a 30 amp 240 receptacle you will actually be able to draw about 40 amps for a few minutes, often longer than the duty cycle of your welder. 30 amps at 240 volts should provide about 175 amps at 30 welding volts. So that isn't the problem. However if your machine doesn't have a switch position for continuous high frequency you won't be able to weld aluminum. The fact it has AC says that it should.
Not just the tungsten, make sure the collet is tight to the torch before inserting the tungsten from the rear and use the rear cap to tighten it into place. As hokey as this sounds I've see this problem on multiple occasions. People try and tighten the tungsten into place with the gas cup end of things and are relying on only the fine threads to make a connection when it needs that lil flat spot on the back of the collet to be tightened down against the torch body.
I had a similar issue like this on my Miller Syncrowave 180SD. There are these point contacts on the back of the machine that needed cleaned and gap adjusted. Also I'm not sure on your experience level with aluminum, but with my Miller you some times have to hit it with more amps than needed then back off, this will get the arc started, thin metal low amps I found took a bit of getting the feel for. This was taken from the online manual for my machine, I'd imagine the 250 is the same. Also to note, I weld 1/4" plate aluminum no problem and 1/2" if I preheat. This is with full 180 amps, pedal floored and slow moving, torch gets real hot fast, lol. I've since converted to water cooled torch, best mod.
Remember zap, you only tickled that corrosion layer on that aluminium with your wire brush. It takes something like 6500 degrees to blast through that layer. So crank the damn amps and don't worry. You'll know if you went too high when the breaker trips. That's it's job.
I think 130 or 140 amps output is what I have it set at output so I don't trip the breaker. So I can go up to 170 on 30 amps? That would be nice. I think the guy before me set the plates at the right height before I got it. I assume they must be the same distance? I don't have the metal measuring sheets (what's the term?) for height. How much was the water cooled torch setup? What kind did you get? I've been thinking about one.
Figure about $500 to go water cooled. Besides the cooler, you need a new torch setup. Metal Measuring sheets? What's that? Are you trying to explain gauge or metal thickness? How thick is your metal?
Talking "feeler gage" to determine gap on contact points? I think that's what he means regarding "thickness." Denis
Yeah feeler gauge is what I was thinking of and couldn't remember. 'Metal dealy thing' - Spoon. $500 for an aquarium pump + copper tubing?? Whaaaat?
That's what is used to measure the gap, I've also heard them referred as thickness gauge, I prefer feeler gauge myself. My conversion was much cheaper and simpler. I purchased a WP18 torch (WP17 is stock on my TIG) as the parts interchange with the WP17. I ran my own water hose/lines and attached to stock cable, had to modify the torch a bit to connect my own hose. I then put a cheap water fountain pump in a 2 gallon bucket and filled it with coolant. Been using for over 8 years now with no issues. Even when I run it hard at full amps the coolant just gets warm. Rule of thumb, do not use automotive coolant, it will over heat and clog the torch. Use automotive washer fluid or buy the expensive coolant at weld supply shop. Washer fluid works great, it was also recommended for use in our induction braze machine at work, it flows through the induction coil. You want to use the deicing washer fluid as it has more alcohol in it. This setup was also recommended to me by the guy at the weld shop, he did say to use an automotive heater core for as a small radiator, but the coolant never got hot enough for me to worry, so never added. The torch would get so hot I could not hold it with a glove on, now just get warm enough to notice.
Any pics of your setup? I'd love to see it. Any brand in particular of automotive washer fluid that you've found works best? I'm unfamiliar with washer fluids. So the torch is like 13 bucks on ebay, you just have that connected to a hose going to a bucket of washer fluid and a small aquarium pump?
