Ceramic cup

[Terence638]

This is a pic of the ceramic cup that I use. It is a number 6cup.
I weld annodized aluminum at about 150 amps with 3/32"pure tungsten, 25 cfm pure argon and 3/32 AL tig wire.
When welding after a couple of minutes the cup turns cherry red and starts to almsot melt then when it cools it becomes brittle and sometimes it cracks when it cools from the argon post gas.
ive tried to play with the heat and play with the cfm.
Im welding on schd 40 aluminum pipe that is either brushed or polished annodized. Im not sure if the setting are correct, Sometimes i dont have this problem and some times i find that when i weld i dont get the right heat before the annodized coatring blows away and then it seems that it is to late because the base metal just molts up and gets nasty looking and black.
Any Helpful hints?

terence

[dyn88]

are you using a water cooled torch? if not check the owners manual for the torch sounds like you are overheating it.

[HAWK]

Terence638,

What machine are you using? Do you have an adjustable EN balance control? If so, you could possibly have it set too far + such as 60% EN or even less. Is your tungsten balled and drooping? 25CFH is a high gas flow rate for a standard cup and collet set up. Atmospheric air intake caused by shielding gas turbulence could be a real problem in your situation.

[Mike W]

I was under the impression that you need to remove the anodizing. I tried a piece that was anodized. I got it to weld but had a lot of black specks on the surface. It also welded different than clean aluminum.

[HAWK]

MikeW,

If you are using an inverter with a high (400-500 PPS )pulse rate with a He/AR mix, you can weld through the anodized coating. I do it with a Dyn 300DX and 75%HE/25%AR

Also some larger machines like the Sync 350 do a good job welding anodized aluminum using 100% He shielding and no pulse. Either way you have to get a small clean spot to start the arc.

[fun4now]

need to clean

maybe he should clean it first, he dosent seem to meet any of the situations HAWK just mentioned for welding anadized.
he is running pure tungsten so probly not a inverter?
and running pure argon.

Terence638
we could use a lil more info here
what welder are you using, and what settings?do you have to weld through the anadized or can you clean it first?

[Terence638]

Sorry about the lack of info,
i am using a syncrowave 250 dx, water cooled torch about 25' of lead. The balance is set at 3 which according to the dial is at the optimum cleaning setting., But like I said it does not happen all the time. but I like the Idea of cleaning a starting point at which time the coating would beremoved as I weld and i wont get into a hot spot (my term) where the base metel seems to melt evn before th ecoating is molten.
I also have the finger slide control that i play with, Im not sure if I should ,at first arc, thumb it up to max or should i start slow and let the metel adapt to the heat before maxxing?
Also as far as cleaning the annodized I guess i could clean it first but in the past I found that the abrasives i was using were to damaging to the base and recently(due to this site) found the proper discs I should be using to clean. Also on the T-tops for boats there are about 30-40 welds that would have to be cleaned which in itself would take up a lot of time,Hence the purchase of the syncrowave 250 DX.
Thanmks
Terence

[HAWK]

Terence638,

Move your balance toward the negative side (penetration) -even just a little bit. Ditch the pure tungsten and use ZIRCONIATED TUNGSTEN alloy electrodes. They will handle the heat better and you should notice an immediate improvement! Yes you will lose some arc cleaning action, but that + balance is really heating up your electrode and torch. I think you will find this to be a great help with your problem.

I can take my Dynasty 300DX and turn the balance down to 50% and meltdown a torch, not just a cup. Why? The more + electrode balance applied to the tungsten the more heat the tungsten and subsequently the torch must sustain. This requires larger tungsten electrodes and heavier duty torches.

The zirconiated tungsten alloy is a great electrode! It will not spit or droop at high temps and is the preferred choice of operators requiring X-RAY quality welds for these reasons.