Need an opinion or advice.....

[piniongear]

I have a Dynasty 200DX running a WP250 -20 water cooled torch.
Using Argon gas and welding 1/8 inch steel.

My problem is when I first start welding there a bright flash and a short loud hissing sound coming from the torch.
Quickly the hiss stops and all is quiet and the weld is normal after that.

So my question is.... What could be causing this?
I suspect there must be a leak somewhere allowing air to enter the torch, but if that were the case, I would expect the weld to not get quiet and there to be much browning around the weld. That does not happen.
This is the first time I have had such a problem.

And yes, when welding aluminum there is always noise from the torch, but welding steel it should be a quiet process all the time.
Perry

[Jayare123]

If you're using a um lesser quality auto darkening helmet a lot of times they're slower and you get some extra brightness just at first and the gas seems to build up a little extra pressure in between use. If you make a weld then immediately make another weld does the gas sound occur on second pass?

[ryanjones2150]

Is this a sudden change or has that machine always done that?

[piniongear]

I have a good quality welding helmet (Lincoln Arctic, I think).
And yes, quickly making a second weld the hiss still occurs.

This is a recent problem,. starting yesterday.
. I weld a lot of aluminum and steel with this helmet and the flash only happens when the 2024 helmet battery needs replacing. And the flash last a long time when it has a bad a bad battery..

I have a new battery installed and the flash is quick, maybe a half second then it is done and the weld goes smoothly.
The first hiss happened a few days ago and I replaced the small O ring on the torch cap and it cured it.for 2 days. Now the hiss is back.
That is the reason I suspect an air leak in the torch.

Ryan, this is a sudden change. The welding has good without a problem for the past year or more. Suddenly it starts to hiss and the momentaty flash.
Thanks guys for your comments.
perry

[tarry99]

Does that 200DX have gas Pre-flow and Post Flow Timing? your Pre-Flow may be set to come on early?

[piniongear]

I always have my pre-flow set at the same setting and that has not been changed.

[aametalmaster]

I always have my pre-flow set at the same setting and that has not been changed.

Maybe it changed itself. My MM252 used to do that...Bob

[piniongear]

Maybe it changed itself. My MM252 used to do that...Bob

I will check, but when I press down on the foot pedal gas flows for a half second or so then the arc starts, along with the hiss and flash.
That tells me gas is flowing so there should be a silent start to the arc. The hiss and flash make me think air is being induced with the gas flow.
I dunno, as I am far from an expert on such things.
perry

[ryanjones2150]

Hmmm....maybe try a different torch and see what happens. Or at least change out the torch head.

[piniongear]

Hmmm....maybe try a different torch and see what happens. Or at least change out the torch head.

Good suggestion and if I had another torch I would do that. This thing has me puzzled.
It was welding fine for several years and now suddenly it hisses when the arc is first struck.
I will have to keep looking at it I guess.
perry

[Ltbadd]

If you were getting air in the gas the tungsten would deteriorate and the weld would have pin holes. Can you take a video and post back?

[gnforge]

Been a wile but I seem to remember that happening to my Dynasty. Not sure how I fixed it but I think it was a very fine crack in the cup couldn't see it at 1st but if I remember that's what fixed it. <br />
I'd try new cup if haven't tried already. If that wasn't it I still think it was some type of fine leak <br />
Sorry can't remember for sure but with trial error I figured it out. Hope it helps

[piniongear]

The tungsten was deteriorating badly.
In fact with the last go around the tungsten was almost welded to the gas lens as well as being severely burned back.

But, I think I found the problem, or at least it is fixed for now.
I had tried a new gas lens, new nozzle, and even a new collet but nothing changed.
I had also installed a new O ring at the handle (end cap) ..
I used one of the red O rings that came with a gas lens kit.

It looked small to me, so I removed that O ring and replaced it with a black Buna O ring from my assorted O ring box.
This O ring was "fatter" than the red one..
I struck an arc and no hissing or flash at all.
Just a silent ignition and a nice blue arc.

So I can only surmise that there was air being sucked in around that O ring.
Thanks to you guys for the suggestions and comments.
If the fix does not hold I will report back.
perry