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Soot in front of weld

Posted: Mon Jan 29, 2018 10:34 pm
by Ant428
Good day all,

I came across a problem when practicing pipe welding. When I stop the weld, I notice there is soot in front of where I terminated the arc. I am using laywire and walking the cup over it. The rod also breaks off the base metal easily when I'm done with a weld. Its hard to see in the pictures, but sometimes theres a lot of soot and I always have to brush it before starting the weld again. Sometimes there is a lot , I don't have a pic of excess soot but there has been a line about an inch long in front of the weld. Also, if I break the rod off the pipe, it cracks off with one bend. Any ideas?

1/8 rod,#8 gas lens, 115 amps. 15cfh
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Re: Soot in front of weld

Posted: Mon Jan 29, 2018 11:20 pm
by Poland308
Might be moisture in the gas. Or contamination \ oil residue on the pipe.

Re: Soot in front of weld

Posted: Mon Jan 29, 2018 11:24 pm
by Farmwelding
Have any post flow? I don't know a whole lot but if I have a rod break off very easily it usually is lacking gas flow so after you terminate the arc is there any post flow?

Re: Soot in front of weld

Posted: Tue Jan 30, 2018 8:26 am
by cj737
When I get "soot" ahead of the puddle, I find it tends to be because my torch angle has gotten VERY acute. This happens a lot when walking the cup vertically, and you get slightly out of position, or are running short on your wire. It does not take but a few degrees of torch angle to make a huge difference, and you may not notice it as you're focused on the arc distance, and can't see the torch angle.

As for snapping off the filler, I'd say its because the wire has become very cool and brittle, or the lightly melted portion of your wire is so thin that it is not very strong. To me, it's not a concern from your description.

Re: Soot in front of weld

Posted: Wed Jan 31, 2018 10:01 pm
by Ant428
Farmwelding wrote:Have any post flow? I don't know a whole lot but if I have a rod break off very easily it usually is lacking gas flow so after you terminate the arc is there any post flow?
Its a squarwave tie 200 so it has auto post flow. I think the problem is the argon isn't wrapping around the pipe, so where it flows off is where there is soot. I think I need less stick out.

Re: Soot in front of weld

Posted: Wed Jan 31, 2018 11:51 pm
by cj737
Ant428 wrote: Its a squarwave tie 200 so it has auto post flow. I think the problem is the argon isn't wrapping around the pipe, so where it flows off is where there is soot. I think I need less stick out.
That says too flat a torch angle to me... if you have a long stickout while pipe welding, you’ll tend to lay the cup back too far and you will get that slot ahead of the puddle at the end.

Re: Soot in front of weld

Posted: Sat Feb 03, 2018 2:17 pm
by Ryan
I recently had a soot issue with my Rebel 235. I was getting black soot in mig and tig post flow. Discovered i had tiny leaks where the hoses connected to the machine. Wrapped the threads with teflon and it didnt happen again. Not saying its the same for you, but may be worth a look. Good luck!