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small bead and good penetration on pipe joints

Posted: Wed Feb 03, 2016 6:14 pm
by arc.ranger
I have been TIG welding for more decades than I want to admit, but I don't do it every day and my skills, while good enough to do good functional work, could stand some improvement. I am no artist.

In particular, when I am faced with, say, a right angle "T" joint in two pieces of pipe, I always seem to end up with a big fillet of metal, particularly on aluminum, even when the tubing is not thick walled.

I have seen what a real TIG artist can do; for example, those guys who do aerospace plumbing or race-car exhaust headers, so I know it's possible to get a really small bead that's right down in the angle.

How do they do this ?? I have tried and tried. There's something I am missing.

Re: small bead and good penetration on pipe joints

Posted: Wed Feb 03, 2016 10:51 pm
by Diesel
How are you grinding your tungsten? What ac balance and frequency? What size filler?

Re: small bead and good penetration on pipe joints

Posted: Thu Feb 04, 2016 1:18 am
by AFR_Autoworks
One of the things I find most important is arc length and tungsten condition. In a corner you will have to run potentially more stick out then you may be comfortable with

Re: small bead and good penetration on pipe joints

Posted: Thu Feb 04, 2016 8:52 am
by arc.ranger
Diesel and AFR_Autoworks:

I am grinding my tungsten freehand on a big disc sander, about like a pencil point for steel. On aluminum I will run the smallest melted ball-end on the electrode that I can get away with. I usually set my AC balance to "neutral". I am choosing filler just like I would for welding flat plate - somewhere around the thickness of the tube wall, maybe a bit less.

AFR - I try to keep my arc length as short as I can. Can you elaborate on "tungsten condition"?

I didn't want to get too long winded in my original post, but the problem seems to be that I get my electrode right in there and start the weld OK, but then the height of this deposited metal causes me to back off, so I end up riding the top of this big glob of a puddle all the way around the joint. I have not been able to figure out how to "get ahead" of this puddle with the electrode and get it back down into the joint. This can't be the right technique.

Thanks for the replies, guys

Re: small bead and good penetration on pipe joints

Posted: Thu Feb 04, 2016 9:40 pm
by Diesel
Sounds fine. For finer beads I'll sharpen it and just blunt the end. Seems to be a little more stable than a balled end. It may be as some as adding a little less filler. To me aluminum is like caramel. It doesn't want to flow like steel. I use a little manipulation and only add filler when its getting dry and wanting to pull out of the root of the joint and stop flowing. Also a tip I picked up from Jody is to run over the joint and allow the cleaning action to take place before welding. He only does about the first inch or two as I recall, a good way to start off clean. Maybe some more experienced guys can aid further.

Re: small bead and good penetration on pipe joints

Posted: Fri Feb 05, 2016 7:47 am
by motox
sounds like you might be adding wire to soon
and not wetting all the way into the joint.
also watch torch angle length.
craig

Re: small bead and good penetration on pipe joints

Posted: Fri Feb 05, 2016 8:48 am
by arc.ranger
Thanks for all the suggestions.

I also took a look at the video presently highlighted on the home web page; it's about tee joints in aluminum, which is really what I am talking about when you come right down to it.

I now have a lot of stuff to try when I get back out to my shop. I will practice on T joints .

While we are at it, has anybody tried to weld these joints backhand ? That would seem to be a good idea, since you could keep the electrode right down in the V. I have never done it, though.

Re: small bead and good penetration on pipe joints

Posted: Fri Feb 05, 2016 2:35 pm
by Diesel
You're talking about dragging the puddle? I don't think that's what you want. That's generally used for high build for mismachined parts.

Re: small bead and good penetration on pipe joints

Posted: Sat Feb 06, 2016 3:59 am
by Oscar
Image

Also, increase your balance towards EN, but not so much you get black specks/soot.

Re: small bead and good penetration on pipe joints

Posted: Sat Feb 06, 2016 10:15 am
by arc.ranger
thanks, Weldmonger.

Unfortunately, my trusty old Synchrowave can't do frequency. I do have a pulse controller on it, though, which I don't use all that much. Using a pulse should help focus the arc, and your suggestion about a more negative electrode is a good one.

Re: small bead and good penetration on pipe joints

Posted: Sat Feb 06, 2016 4:54 pm
by Oscar
arc.ranger wrote:thanks, Weldmonger.

Unfortunately, my trusty old Synchrowave can't do frequency. ....
that right there is the #1 enemy, unfortunately, when needing to pinpoint the arc in fillet/T-joint configurations. I know it can be done, but being able to adjust AC Freq sure does help a lot.

Re: small bead and good penetration on pipe joints

Posted: Sat Feb 06, 2016 7:36 pm
by GreinTime
Oscar wrote:
arc.ranger wrote:thanks, Weldmonger.

Unfortunately, my trusty old Synchrowave can't do frequency. ....
that right there is the #1 enemy, unfortunately, when needing to pinpoint the arc in fillet/T-joint configurations. I know it can be done, but being able to adjust AC Freq sure does help a lot.
Frequency is a crutch for some, and a scalpel for others. People TIG welded for close to 40 years before frequency adjustment became available to everyone and laid down beads that would make some of the Internet fan boys mess their britches up.

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Re: small bead and good penetration on pipe joints

Posted: Sat Feb 06, 2016 7:53 pm
by TigMonster
To do this ( this is a scrap weld..dont judge lol) i just dip and move. Keep your torch pointed in the direction you are going and it will be fine.Image

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