Just bought a new machine and have been running some nice beads on 4 mm ally with a 3.2 Zirconiated tungsten. Ac balance at 35%. The tungsten has a nice small ball after welding but the first 2 cm of the tungsten including the tip has This brown dusty colour. I’m using an 8 cup gas lense with 2 secs post flow. Gas flow hasn’t changed from the old machines..
Anyone have some suggestions of why this is happening?...
Post Flow does two things for you. One thing it does is provide inert gas coverage over the weld as it cools. You must hold the torch in place over the weld after the arc stops, for this to be effective. The second thing it does is protect your hot Tungsten from getting oxidized while it cools down. That is another reason to hold the torch still at the end of the weld. Post Flow can't protect a red hot electrode if it is quickly moved, and waving around in the air.
The post flow time needs to be long enough to let things cool to a safe level, before flow stops. In other words the bigger the electrode, and the hotter the electrode, the longer you will need that protection.
The post flow time needs to be long enough to let things cool to a safe level, before flow stops. In other words the bigger the electrode, and the hotter the electrode, the longer you will need that protection.
No sense dying with unused welding rod, so light 'em up!
not enough post flow. had the same thing the other day when i incorrectly adjusted the machine.CamPaice wrote:Just bought a new machine and have been running some nice beads on 4 mm ally with a 3.2 Zirconiated tungsten. Ac balance at 35%. The tungsten has a nice small ball after welding but the first 2 cm of the tungsten including the tip has This brown dusty colour. I’m using an 8 cup gas lense with 2 secs post flow. Gas flow hasn’t changed from the old machines..
Anyone have some suggestions of why this is happening?...
the other thing is go down a cup size or two.
tweak it until it breaks
I agree with you, but if there is long enough Post Flow, it should help keep the contamination from affecting the electrode. It could be something on the metal surface rising as 'smoke' onto the hot electrode.Spartan wrote:Yeah, but the tungsten oxidizing due to inadequate post flow shouldn't be turning their tungsten a "dusty brown". Sounds like there is some contamination going on there, also.
My earlier post was just info for people trying to figure out how long they should be setting their Post Flow.
No sense dying with unused welding rod, so light 'em up!
Thanks for all the info. The ally is very clean, so I,m leaning towards post flow. Still welds really nice, just never seen this happen before. I might throw another tungsten in there and up the PF to 6 secs as suggested. I also noted the inside of the cup isn’t looking to clean, looks like some ally has stuck to it after accidentally dipping the tip. Time for a new cup as well ?..
i havn't had to much issues with dirty cups and i usually take the tungsten for a swim or blow up crap on dirty aluminium.CamPaice wrote:Thanks for all the info. The ally is very clean, so I,m leaning towards post flow. Still welds really nice, just never seen this happen before. I might throw another tungsten in there and up the PF to 6 secs as suggested. I also noted the inside of the cup isn’t looking to clean, looks like some ally has stuck to it after accidentally dipping the tip. Time for a new cup as well ?..
however worth dropping a size or two.
i'm sure your issue is just post flow.
the other issue if your getting dirty cups is to make sure there is no aluminium filings left around the bench. they tend to get sucked into the torch. i have no idea how, but i have seen it many times (cause i'm such a clean tidy person lol)
tweak it until it breaks