pp256 on aluminum

Hey guys I am new to tig welding and I am trying to figure out if this is operator error or if anything is wrong with the machine. I am in the hospital right now and writing this from my bed so I dont have the machine in front of me but I will try to describe the problem. So I was trying to run some beads on aluminum and basically my electrode just kept melting. First I was using 1/16 2% thoriated at relatively low amperage, AC, torch connected to negative lug, basically no matter how low I turned down the amperage the tungsten just kept melting. So I switched over to dc and started on some steel. Everything was fine didnt seem to eat up the tungsten nearly as bad and I could start to make a puddle and everything seemed fine. ok, switch back over to ac and the electrode melts right away. I cant remember exactly right now what all the settings were but I was trying to weld up an aluminum wheel. I know its not the best thing to practice on but its what I had for a big peice of scrap. I had a friend who is a professional welder at the savannah river nuclear site come in and take a look for me to see if he could figure it out and he couldnt. He seems to think that the machine isnt really set up for aluminum but I know it is. I've seen the welds on this forum so I know the machine is capable if it is working properly and if the settings are right. I had my regulator set to 10-11 pure argon. What he kept saying is that he doesnt hear the high freq staying on like it should. I know the hf start is working because I took the work lead off the work to make sure. If somebody could give me some settings the way you guys would set up the machine if you were trying to run a puddle on a wheel I can figure out if it is me or the machine. I also tried on a much smaller thinner scrap of aluminum angle and it still burned and balled my tungsten up, even when I switched to 3/32. went back to dc and the tungsten held up fine but cant weld aluminum in dc. Oh yeah one more thing. in the tips and tricks video jody says the torch that came with his machine is an air cooled torch but I thought it was a water cooled torch? anyway I am really bored in here wish I could get back to the shop.

He probably requested the torch.

No, the HF doesn't stay on on an inverter. The switching frequency is so high that it doesn't need anything but HF on start.

10-11 may be a little high. Turn it down. It registers in Metric.
That is around 22 cfh.

What amp are you welding at? Are you using the foot pedal? Have someone watch the amps as you use it. Is it controlling the amperage throughout the range? Or does it seem to exceed maximum set amps? What amps are you using?

What is your percent AC balance? Try turning it down to about 25% electrode positive. Turn your ac freq to about 130 or 150.

I hope you get out of the hospital soon. Are you ok?

I was varying the amperage from 40-200 trying to cancel the effect. I was using the footpedal. When I set the pulse on the unit I noticed the amperage display toggling between set and background even when the torch was off. I assume that is normal. I will try the settings above when I get back to work. I'll live, I have a staph infection in my arm that doesnt want to give up.

Yes,
It is normal for the pulse to bounce between two given amperages even when it is shut down because it changes from giving actual readings to reading the presets.

What effect were you trying to cancel?

First, start by turning the pulse off.

But, if you are using 1/16 tungsten much above 40-50 amps, it will ball all up, no matter what. Inverters can really cook small electrodes, particularly.

Step up to a 3/32.

I had a bout of mrsa earlier this year that got in my scalp. Not a pleasant thing. I am sure down in the arm is much worse.

I hope you get better.

Yeah I forgot to mention that I had switched to 3/32 also with the same results. I was just hoping that there was something that I obviously had connected or set wrong that would explain it. They released me from the hospital today. Hopefully I will be able to return to work on tuesday. Hopefully I will get a chance to try it again soon.

Hey wrenchtamer, hope you are out of the hospital bed ( they suck ive been there a bunch)
And Mark is right as usual but one suggestion I have is to take off the foot pedal as well to rule out that part as well. And use 2T to check the arc settings.
Just a thought.
Gary

Hi Wrenchtamer, Just was watching the thread and wondered how things are going? First of all with you self man! Hope your immune system is kicking some serious butt on that infection!

Second hows the tungsten issue going? Didn't ever hear where your ac balance was set? That's the most obvious culprit from your description i would think. Also as was said go back to the basics when ya have a problem and turn the pulse control off. I think your welder friend may not be a TIG guy if he didn't think the machine was "set up" for aluminum welding, unless it was just a symantics thing, and that was his way of saying that he believed that the machine was not operating as it should. let us know buddy! - Lou

Yes I am out of the hospital and back on the job finally. Thank you all so much for your concern. I have been testing the machine sporadically since I got back and have followed all of your suggestions. I had already switched to 3/32 2% thoriated but I eliminated the foot pedal and pulse, lowered the amperage and tested with two different pieces of architectural aluminum angle. Changed the ac balance to about the nine or ten oclock position and frequency to about the three oclock position. I didnt mention before that I am still running the water cooled torch without cooler so that could have contributed to it. So I have been afraid to try to run the torch for more than a few seconds at a time, although the torch head never really got that hot. so one test peice was about 1/4 inch wall and the other was maybe 16 gauge or so. very thin. Was able to run a little bit of a bead with no filler and finally see where the puddle started to form. I had just purchased a new mask from the snap on guy and it must not be suitable for tig welding because just when the puddle starts to form the darkening drops out and blinds me so I cant see jack. He is exchanging the mask for anther one with four arc sensors and more adjustability should be here on monday. I can see the etched zone though, and see where the puddle started to form on both test pieces. No significant electrode melting but it did blunt the tip pretty quickly. I'm trying to work up a water cooler (wp18) but being out of work put a hold on that. Does it help to run air through it? I think the guy that I had here is used to a machine with continuous high frequency and doesnt really know about other machines besides the one he uses at work. Also I think the wheel I was trying to weld was just way too thick and nott really weld friendly anyway. If anything I probably should have been gas welding it. anyway gotta open the shop now. Will keep you posted.

Wrenchtamer,
glad to hear your out of the hospital. But you can use the torch without a cooler until it gets pretty hot . I think it will be OK until you get to 160 amps for a while of welding.
You can also set up the water cooler with the wate hose methode if you are concerned about using it , only cost about 10-20 bucks with the 2 fittings from home depot and some tubing to get the hot water out of the garage.
There is a thread about it somewher on the site just search homemade water cooler. It is just a plastic reducer for the water hose and some clamps will get you running. But the water cooled torch can be run without the water until it gets hot to the touch then just let it cool off a bit.
Gary

Well I finally stepped up from 3/32 tungsten to 1/8 and switched from thoriated to ceriated and it seemed to make all the difference in the world. Seems like the criated is much more resistant to melting in AC. It still starts to break down at about 50 amps pretty quickly. Can anyone give me a good description of how the ac balance knob settings work? The readings on the dial seem a little ambiguous. has anybody been able to weld auminum with 3/32 2% thoriated on the 256? With the 1/8 the bead looks great and I can control the cothodic etching right down to nothing but it seems like it just melted the hell out of the thoriated real fast. I also bought some 1/8 thoriated but havent tried it yet. I think everything is working properly just want to be sure. I'm still wrking on a cooler. Got a couple of new heater cores and an aquarium pump. Nce high speed blower for heat exchange I just need to figure out what to use as a housing for it all. I rarely replace any evaporator housings but that would be perfect.

Been a couple weeks and I haven't gotten any feedback on my last post. Just trying to figure out what I need to know about ac welding aluminum. Settings, tungsten size and so forth. I have seen lots of pictures of welds on this forum tht were done with the 256 so basically I'm trying to get some opinions on the best type and size of tungsten and if the melting thing has been encountered and dealt with successfully by others. I woud appreciate you guys input.

Check out weldingtipsandtricks.com under pulse tig welder. This will give you the best sense of what you need to do to set it up. But I put the balance between 20-30 percent.