no 9 tig head problem

[paul-b]

hello im paul
over the years when i find myself in tight or awkward positions to weld. i change my torch head to an f9 especially on thin wall stainless the problem im gettin is a black weld
i have checked all connections
this has happened a number of times over the years with different sets and torches

 

[Richard.]

Do you mean a dull grey appearance or black soot around the weld.
Both are caused by different things
A dull grey weld is usually caused by over cooking the weld. (Going too slow or too high on the current) this tends to cook out the alloys and create that dull grey appearance.
Black soot is usually a contamination issue. More common with aluminium. This could be caused by a gas leak but you say you've checked that so assume that's ok. Flow rate? Too low or too high can have the same effect. Be much easier if you put a pic up to diagnose. Welcome to the forum

 

[Piero]

Hi

Whats happening to the tungsten when you get this black weld???? is it burning back at all.

is it a black weld your getting or is it soot

 

[Piero]

you just beat me to it Richard

 

[paul-b]

thanks for the email
ive tried adjusting flow rate

Do you mean a dull grey appearance or black soot around the weld.
Both are caused by different things
A dull grey weld is usually caused by over cooking the weld. (Going too slow or too high on the current) this tends to cook out the alloys and create that dull grey appearance.
Black soot is usually a contamination issue. More common with aluminium. This could be caused by a gas leak but you say you've checked that so assume that's ok. Flow rate? Too low or too high can have the same effect. Be much easier if you put a pic up to diagnose. Welcome to the forum

f

you just beat me to it Richard

hi again
as you may im new to site so not sure if im replying correctly
thanks richard. piero for your reply
this has happened to me occasionaly over yhe years
it is definately the 9 head
today after even taking welding set apart to check for leaks inside
no leaks
i put a 17f head on and clean as a whistle. it is definately a lack of argon to the pool sorry tungsten ok

 

[Jim Davey]

Are you using a big enough ceramic in the small head? Is the ceramic end glowing red hot and cooking the gas? If your gas flows are there and you're not experiencing a leak either your torch is getting too hot or your gas coverage area is too small for the size of the weld puddle.

It could also be excessive gas flow causing air to be dragged into the shielding gas column, too much gas can be just as bad as not enough.

 

[paul-b]

hi again as you may of noticed i am new to this site
thanks richard piero for your reply
its not often i use a 9 but have done without any problems on occasion
if this was one off i would just replace the head but the head is brand new
i took the set apart today no sighn of any leaks i put together a dairy inch an half butt rolled it with the 9 done about a third
changed the head to a 17f and clean as a whistle

 

[AndersK]

How high amps have you been at with the 9?
They are normally rated at 125 amps DC. Going over that repeatedly will melt the tiny gas line in it and it will eventually leak around back cap even if it looks ok.

Done the thumb up the cup trick to check for a leak?