Dynasty 200 surface contamination issue

By waltworks Date 03-06-2007 19:09

Guys -

I'm hoping someone here will have some ideas for me. I'm a bike builder, and a TIG welder, and I've recently (in the last several months) started having troubles with both my Maxstar150STR and Dynasty200 (both air/inverter machines).

The original thread (on a bike building forum) is here, along with some pictures: http://www.frameforum.net/forum2/index.php?showtopic=2938

Here's the original post:

Ok, at this point, this issue has confounded me, the good folks at General Air, my old welding instructor, and everyone else I could think of to ask. Looking for any kind of weird idea at this point - I am baffled.

The symptoms: I'm getting greyish, lumpy deposits on the surface of my tig welds. Glowing embers are visible in the weld pool while welding, as well. Clearly, something non-inert is getting to the weld, but I'm stumped at this point as to what it might be. The arc also has a tendency to wander and is relatively hard to control. Strength of the joint seems unaffected - I've done some destructive testing to make sure. But the appearance is sub-par from what I'm used to doing. I'll try to post a picture or two tomorrow.

Solutions I've tried with no effect, in no particular order:
-Check (no leaks) then replace regulator, all hoses, torch body and parts.
-Replace entire welder (hey, I always wanted a Dynasty anyway...)
-Use different type (ceriated and thoriated), size (3/32 and 1/16), and brand of tungsten.
-Use different gas cups and lenses of all different sizes.
-Change argon flow rate to torch from as low as 5cfh to as high as 35.
-Replace argon tank (multiple times) and try argon from another supplier.
-Replace tungsten grinding wheel with new ($$) diamond wheel.
-Sharpen tungsten to fine point, sharpen tungsten then grind flat, etc. I've pretty much tried every shape of grind you can think of.
-Close all doors/windows and completely eliminate any possibility of drafts (it's notable that I never used to have this problem when welding with a fan running on a hot summer day).
-Use different type/size of weld rod (ER70S and 880t in .035 and .045).
-Use different cleaning procedures (acetone vs denatured ETOH, stainless wire brush vs emory cloth vs scotchbrite vs 3m metal cleaning pads).
-Use different tubes (happens with 4130, everything made by True Temper, all Nova/Columbus stuff that I have, and even old Tange prestige).
-Backpurge/don't backpurge tubes.
-Change welder settings all over the map - from 70 to 120 amps, pulse rates from .5 to 2/second, different background/peak, etc, etc.
-Swap polarity.
-Keep all hoses/lines in warm, dry place for 2 weeks to make sure no moisture is inside.
-Move entire welding setup 10 feet to another location in the shop.
-Clean welding table/replace ground clamp to ensure good ground.
-Probably a few other things I can't remember now.

I've done some sample welds using other equipment at other locations and I have absolutely no issues, so it's not anything about torch angle or technique (and given that nothing about my technique changed in the last 3 or 4 years, whereas the problem started about 4 months ago, I doubt that it's a technique issue).

I'm pulling my hair out on this. Any clever ideas?

-Walt

By Lawrence (*****)

Date 03-06-2007 19:53

Troubleshooting is fun! Step by step to eliminate what the problem cannot be.

To quote Sherlock Holms: "'When you eliminate the impossible, whatever you have left, no matter how improbable, must be the truth."

This may seem wierd, and I know you have done alot of things already, but give this method a try.
Aluminum is the canary in the coal mine.

Take some aluminum over 0.063 thickness and run some stringer beads with the same torch angles as your steel production welds.

AC
pure argon
Frequency 60 hz
Balence on your Dynasty set at 55-60
1/16 or 3/32 any tungsten but pure.

If the surface condition of your welds are clean and you see sufficient etch at the toes, than you can count out contaminated gas, leaky torch, bad electrodes, contaminated gloves and vagrant breezes. If you have problems here than we can start to deal with items one at a time until the weld is clean and the problem solved.

Get this out of the way first...
If all checks out than we start to look at other things like parent material, filler metals etc.

Let us know what your results are and we can go from there.

By aevald

Date 03-06-2007 20:19

Hello Walt, I think Lawrence hit the nail on the head with his first suggestion to rule out the gas supply, machine and hardware issues. I also believe you may very well have a filler metal, parent metal, metal condition, or chemical contamination issue going on here. The little ember you were referring to in your description of the puddle sounds a lot like silica, that in itself isn't necessarily a completely bad thing, however it can certainly add up to other issues. There have been some past posts and threads that have dealt with apparent contamination issues. Cutting fluids, metalworking fluids, metal paint identification compounds, can have a dramatic effect on GTAW welds. Metal anti-rust compounds can also deal a death blow to these types of welds. In one other previous post that I vaguely remember, an individual ran into problems that were caused by welding on the materials and as they got hot, the metal preservatives inside of the pipe started melting and running into the weld joint from the inside and causing problems with the weld. If you are not already doing so you might also see about very carefully cleaning your mating parts with acetone or some other type of cleaner that won't leave any residue and then using a flap wheel or some other form of power polishing process and then do a test weld. Compare these results to your previous attemps and take it from there. As Lawrence stated: one step at a time and rule out everything as you go. Success in GTAW means CLEAN, CLEAN, CLEAN. Good luck, regards, and keep us posted on your progress, aevald

By waltworks Date 03-06-2007 22:30

Aevald -

Thanks for your reply. I have done the acetone cleaning (along with many other cleaning solutions) and scotchbrite/flap wheel/etc. Many, many different techniques. Keep in mind that I changed *nothing* about my procedures or materials when this problem started happening. The tubes, at this point, are as clean as I can make them, and much cleaner than they were when I had no troubles at all in the past.

However, given that I've reproduced the problem with other equipment (a Lincoln precisiontig setup with entirely different lines and torch), I'm pretty positive there's something contaminating the base material as well. I just can't figure out what it could be.

-Walt

By aevald

Date 03-06-2007 23:19

Hello again Walt, I'm going to get a little wild here. Have you changed the type of gloves that you use, or if you're bare handing the filler rod, are you using any sort of hand creams, lotions, or soaps that you didn't use in the past? Are you using a different filler wire concerning heat #'s, or are the tubes from a different manufacturer or of a different heat #? These are also suttle yet possible causes for some of what you might be seeing. Just a few more items for thought. Regards, Allan

By waltworks Date 03-07-2007 00:20

Hi Allan -

Yes, I've tried several different kinds of gloves (and tried soaking the gloves in acetone before wearing them). No change. Tubes from all manufacturers and all types of filler wire (ER70s and 880t from Weldmold being the 2 primary ones) are equally affected.

-Walt

By aevald

Date 03-07-2007 09:00

Hello again Walt, I had quite a response set to send your way and then I pulled one of those old guy, doesn't know how to operate the computer stunts, and lost it. So I'll try to give it another shot. One of the things that I was going to say is that I would certainly be frustrated in your position when I hadn't changed anything and then I ended up with the sort of issues that you are seeing. One of my questions has to do with the lincoln machine that you said that you tried and still had the same issues. Was this a machine that you brought to your shop and hooked up to your gas supply? Or was this a machine that you brought in completely using a set-up from another shop including the gas bottle? Or was this a machine that you used at somebody else's shop that you brought your parts and filler materials to and ended up with the same problems?
Next question. Have you tested your input power to see that it is at the correct voltage? I am making an assumption that you are possibly using 230 volt single phase power on the Miller Dynasty 200 and if my memory serves me correctly the Maxstar150STR can also be run on 230 volt single phase power or possibly 110 volts, but you're likely not using the 110 volt input. That would lead me to another question along these same lines. Have you made any changes in the wiring in your shop or are you using any extension cords or other modifications to input power that you hadn't previously been using? Do you have any way to check the amp draw on the individual legs of the supply power to the machine when it is being used? If so, note carefully any major amp draw variations between the 2 hot supply legs to the machine, likewise check the voltages on these two legs for any major differences. If you do find something strange going on here with the voltages or amperages and you're not electrically savvy get ahold of a qualified electrician and have him/her check it out for you.
The only other crazy thing that I can come up with, would have to do with the torch and ground connections to the machine and it is unlikely that this would be the issue here since these machines do not have current selector switches other than the dynasty having an AC/DC selector. My thought here would have to do with the terminal that the torch and ground cable are plugged into. If this connection is reversed(I don't know that this is possible on the Maxstar since I believe that it has a euro-style torch connection), the way that the high-frequency is imposed into the circuit doesn't allow it to operate correctly. I have purposefully done this to see the result and when you try to use the AC current with the machine hooked up this way it will do some really weird things. I don't know how the DC would act as I just haven't tried it. The first obvious result would likely be the tungsten going away rapidly since you would be trying to operate it on reverse polarity. Here again another thought to ponder. Well once again good luck and keep us posted. Regards, Allan

By Kix

Date 03-12-2007 16:40

take your tungsten out and put your thumb over the cup at about 15 to 20 cfh and see if your ball in your flow meter still floats a bit. If it does your have a leak and your sucking air. I'm willing to bet your sucking air somewhere or your not getting 100% argon out of your bottle