Dynasty 200DX Aluminum Cratering

[Swift]

I've had my Dynasty for several months now and it really is a nice machine. One thing that I have had some trouble with is the cratering at the end of a weld. No matter how slow I come off the pedal, I get a small crater. I learned to TIG with a Syncrowave 180SD and did not have this problem. It just seems like no matter how slow I reduce the current, the arc cuts off at a higher amperage than with the 180SD.

Just in case, here's the specifics:

1/8th inch 6063 fillet or butt joint.
3/32 ceriated (sharpend and slightly blunted).
3/32 4043 filler.
Argon @ about 18 cfh indoors.
120 amps.
Balance: 78%.
Frequency: 70 Hz.

Thanks for any suggestions!
Chris

[Matt 5.0]

Swift, I am having the same problem with my new Dynasty 200 DX. Thought it was me, no matter how slow I slope it down with the pedal, it craters. Interseted in seeing if anyone knows....subscribing.

[dseman]

Swift asked this question on the hobart board and I already responded to it over there. I quess he didn't bother to check his posts, or just doesn't want to say thanks. In either case Matt, you'll find that a 3/32 tung covers 15-130amps. As you ramp down on the amperage, add a dab of filler at the end. This will solve your cratering. There is nothing wrong with the machine. You just need to learn some AL techniques. Depending on your tung grind and arc distance, you should be able to hold at arc at 15 amps all day long. The puddle should have no problem freezing if it is on 1/8th stock.

-dseman

[Matt 5.0]

Thanx dse, As a Boilermaker, we don't work with AL all that much, just trying to get some practice.

Thanx again

[Swift]

Easy there dseman. I checked my post and appreciate you trying to answer it. However, you must not have paid close attention to my post in the first place. I had no problems with the 180SD but do with the 200DX. Therefore, my tungston grinding and arc length must not be the problem. Thanks for trying though.

Chris

[dseman]

Well I've run the 200dx at a miller trade show and had no problem ramping down and terminating the weld properly. HAWK on this board owns one and has never indicated he had a problem either.

-dseman

[dseman]

Swifty,
Oh yeah, next time you post a question and a response is given, please try to follow it up with another reply so that we can confirm that the problem is solved. If no reply is given, we believe that you've gone away happy and the problem is fixed.


-dseman

[HAWK]

Hey Guys,

Here's the bottom line: Inverters and transfomers are both excellent tig power sources. However, they weld differently. Before blaming your equipment make sure of your technique and how it applies to the technology you are utilizing.

Let's not cut the thread that binds us to this forum: The joy of welding. For those unfamiliar with the Dynasty and want to play here is an exercise with 1/8" aluminum sheet.

Regarding the welding on the 3000 series aluminum here is where I would start
- 4043 - - argon flow rate of 15 to 20
- set the Dynasty for
AC
HF IMPULSE
RMT STD
POST FLOW (20 sec)
MAIN AMPERAGE ( 100-125 )
AC FREQUENCY ( 100 Hz to start)
BALANCE (75%)

2% 3/32" thoriated tungsten is fine. grind it to a point but than take the point off by grinding a small flat on the end on the tungsten. The stick out of the tungsten should be around 1 ½ times the diameter of the tungsten. Ceriated tungsten will also work well.

These parameters work well. They are not mine, but belong to one who is very familiar with the D200DX and how it behaves.

[Matt 5.0]

Thanx for the heads up Hawk. Sounds like good info, I will try it out as soon as I refill the Argon bottle. Also, what's the deal with 2% vs pure tungsten. I was always taught that 2% will contaminate AL, but lately I have been hearing that it will work fine. Thanx guys

Matt

[HAWK]

Matt 5.0,

In very critical applications thoriatied tungsten can contaminate the weld and is usually only detected by radiographic testing. Ceriated tungsten is your best bet on an inverter like the D200. Most applications are not that critical.

[HAWK]

Matt 5.0,

Just an after thought. There are a variety of tungsten and its alloys available. Some folks like the zirconiated alloy with an inverter. I am sure there are tech reasons for a specific alloy on when and where to use. The guys I know having to face radiographic testing on a weld to weld basis (they are using Dynasty 300 machines) are using ceriated tungsten. I think it is partly a personal preference. I like thoriated for steel, pure for al on my TB301G with the high freq box, ceriated for aluminum on my Dynasty and am starting to play with zirtung on the Dynasty.

[imported_Blackplague]

Hey Hawk,

I don't think your really going to like the zirc on the dynasty. It spits, and the point starts splitting and deforming. I agree with you on the Ceriated. So far the ceriated is the best stuff going for the dynasty, that i have found. I do want to try some lanthiated though.

[HAWK]

Blackplague,

Thanks for the info on the zirtung. I have some lanthtung, but have not played with it yet. I've got some 16 guage chain guards for a conveyor system to do tomorrow, but they are steel-may mig them. I may have some play time for al if the job goes fast enough. Let me know how you like the lanthiated alloy. I have heard good things, but have never taken the time to test it. I'd like to have a good solid 50 hour week to test weld on nothing but my Dynasty 200DX.