thungsten sot

[Macgyver]

hello helpers.

its an issue ive been having for some time. not big, but abit bothering.
i put a new zirkoniated thungsten. 3.2mm.
but after a few arc starts the thungsten get black up inside the nr 8 cup i use. and after a few or meny arc starts its starts piling sot and spatter further up on the thungsten. Im welding 5*** aluminum. 4 mm
with 5 **** filler rod. i do weld alot of dirty and angle grinded edges and also. sometimes leftover oil from cuts and stuff. ive been thinking that this can be the issue, all that smoke and sot flowing up and sticking to the thungsten.

its bothering cuz when i start my arch, and right where i start my puddle its allways contaminated, and the arc wanders alot, jumping from those sotspotts further up the thungsten.

 

[mfletch]

All I know is the ally has to be clean use a new stainless wire brush

 

[Tom Orrow L]

The dirt & oil won't be helping at all. Give it a light scratch with a stainless wire brush & wipe down with some acetone if possible.
You're using the right tungsten for ally, especially if your metal is dirty as they've got a good resistance to contamination.

Also, maybe increase your gas flow too.. what lpm are you running at?

 

[Macgyver]

All I know is the ally has to be clean use a new stainless wire brush

yea, i use a stainless wire brush, that only have been used to brush aluminum. im pretty sure its the unclean edges and sot spatter from that.

 

[Richard.]

Sounds a silly question but is the welding coming out ok?
If it is and your issue is just a little tungsten contamination then my next Q is do you have suffiecent gas flow and post flow set.

 

[pedrobedro]

Sounds a silly question but is the welding coming out ok?
If it is and your issue is just a little tungsten contamination then my next Q is do you have suffiecent gas flow and post flow set.

I'd agree with this as the gas flow out of the cup should stop any smoke or soot from going back in there. What kind of welder are you using and are you pointing your tungstens with a flat on the end or balling them before you start ?

 

[Jim Davey]

Is the tungsten ok until the postflow stops? If so increase postflow time.

 

[Richard.]

When the arc is shut off the tungsten still glows for a period of time where it's most vulnerable to oxides getting to it and attacking it causing contamination, this is the exact same case for the weld pool. The post flow has both jobs to consider, it is there to protect the weld you've just laid down as well as the tungsten. It also aids slightly with initial cooling too.

 

[Macgyver]

sorry for incredebly slow answer guys,
thanks for answering.

well my thungsten gets dark tho. which i assume is just cuz of heat, and if there is dirt in the cup and thungsten get really hot i think after postflow goes away it sucks dirt from the cup sides,

So my preflow is now around 1.5 sec. and postflow is around 3.5. but i also have a downslope on the amp on around 1,5 sec. before i wrote this i had around 1 sec after the AMp downslope. wich i think was the reason for dirt getting packed up on the top of the thungston wich makes sence when u think about it, it is the last part of the thungsten to get cool again, and also vonerable for air to get in there and crap things up. since i changed it up, with both postflow, and preflow its been much better. but like i said. the thungsten gets dark, all the way up to the top of the thungsten. and what i weld isnt critical strengt vise.
but u know how it is when ur getting better and better and fewer and fewer things need improvement, and frustrating sotmarks on eatch lap shows. u get more and more ****** at those marks .

Ill se if i can snap some photos of the issue, for the comunity to also be able to understand if thay have same problem .

 

[Macgyver]

I'd agree with this as the gas flow out of the cup should stop any smoke or soot from going back in there. What kind of welder are you using and are you pointing your tungstens with a flat on the end or balling them before you start ?

i might now have answered the spessific questions but ill do so here.
yea the welds are fine and shiny as thay should be the first 2-3 starts and stops. its after that the starts spessificly, and when the thungsten in cold too.
When i start immiditly the start comes out perfect as assumed. so im pretty sure it was lack of postflow and alittle the preflow.

Machine is : Wsme 200 Pulsed acdc tigwelder.
3.2 mm tapered electrode. usually allways make a taper on it. and let it ball up naturaly, even if it sometimes with AC balance low it tends to sugar up on the tip.
welding with zirconiated thungsten, and only have experience with that. i weld with 2.4 thoriated 2 % .3 mm aluminum or lower material thickness. with also a tapered electrode. but with the thoriated thungsten ive had no issues. maybe becaus of less heat and just less trying and failing experience, if that makes sense
100 argon, but that was probably obvious, but im sure there is strange things happening around .

Tnanks again for alot of really good replies. im pretty sure it is the postflow. and i might have a feeling that starting with to high amp also makes a less clean start. i weld mostly 4 mm 5xxx series aluminum and 3 mm 5 xxxx aluminium with 5456 filler metal both 2.4 and 3.2 mm

 

[Macgyver]

The dirt & oil won't be helping at all. Give it a light scratch with a stainless wire brush & wipe down with some acetone if possible.
You're using the right tungsten for ally, especially if your metal is dirty as they've got a good resistance to contamination.

Also, maybe increase your gas flow too.. what lpm are you running at?

thanks for reply.
I weld with a trigger on the torch so my upslope amp is from 70-90 to full thruttle to 150- 140 depending on heating and lengt of weld.

 

[AndersK]

I would say you need at least 5 sec post flow at that amperage. Keep the torch steady while the post flow is running.

 

[Richard.]

and postflow is around 3.5.

I would say you need at least 5 sec post flow at that amperage. Keep the torch steady while the post flow is running.

And the rest......
I spotted the problem into the first paragraph which saved me the big read.
3.5 seconds is less than half what it should be and almost certainly the reason for your contaminated tungsten. Forget the dirt theory and all the other things just turn up the post flow to 7sec and see if it goes away.

 

[langy]

You need a spell checker first bud !!! Your posts are hard to read

 

[Richard.]

You need a spell checker first bud !!! Your posts are hard to read

English is not his native lingo.
I didn't think it was too bad. Better than my Norwegian.

 

[Macgyver]

You need a spell checker first bud !!! Your posts are hard to read

Yea, im sorry i didnt take my time correcting my sentences, i was trying to cover all the replies. :P ill try better next time

 

[Macgyver]

i must say with the same post flow and pre flow but lower amp. welded some edges about 4-5 foot long with a 2 % lanthenaded. It worked better thought. but its a smaller diametre tho. ill experiment some more. but i think this post can be declared ''solved''

 

[Member 66061]

Yea, im sorry i didnt take my time correcting my sentences, i was trying to cover all the replies. :P ill try better next time

I think you are doing a great job of getting your point across. Your written English puts alot of English peoples to shame.

 

[Macgyver]

I made a new post about my bad experience to my recent mig gun. check it out .