On Sat, 11 Sep 2010 19:34:42 -0700, "Jon Danniken"
wrote:

Condition: Welding a tee-joint with square tubing, 2.5" x 0.188
Electrode: 1/8" 7018AC @ ~125A
Position: Horizontal

So I'm trying to figure out how to finish up the shoulder welds on this
square tubing. What I am doing (after I put fillets on the flat corners),
is to run a stringer to build up the shoulder on the bottom piece, chip off
the slag, then come along and weld the top piece to the stringer.

Unfortunately, the buildup on the shoulder leaves slag between the weld and
the bottom edge of the top piece, that even a cup brush won't reach, as you
can see in the following image:

http://img190.imageshack.us/img190/2...agshoulder.jpg

Any ideas as to how I can remedy this situation?

Thanks,

Jon

Looks like the slag is inaccessible because it's under the edge of the
joining piece. Instead of starting with a shoulder, weld that crack
shut first and then build it up.

"Jon Danniken" wrote in message
...
Don Foreman wrote:

Looks like the slag is inaccessible because it's under the edge of the
joining piece. Instead of starting with a shoulder, weld that crack
shut first and then build it up.

Indeed it is under the edge. I still have yet to master welding up a gap,
which was why I was trying to weld up the shoulder, but perhaps this is a
good opportunity for me to learn it.

What rod and technique would you use for that?

Thanks,

Jon

In my experiences with welding miles of tubing, it has to do mainly with the
angle of the rod and the positioning and maintaining of the puddle. If you
wash over to the thinnest part on the T, you will probably blow a hole
unless you are welding it cold, or using a rod like 60210 or 6011. If this
is not a critical application, you could fill the root with a fast pass from
a MIG, or 6011 stinger negative, or even a 3/32" 6010 stinger positive,
clean it up, and put a topper of 7018 that would let you go farther out on
to the thin material, and support the part of the puddle that you have to
flow out there into that crack that has no root pass.

Learn how to wash puddles. It is very valuable when welding a piece of
light tubing on to a base plate so you don't blow a hole in the tube. DO
leave two diagonally placed openings in the weld so water can drain from the
inside. Even tack it so there is a 1/32" or so gap. Unless you are going
to fill it with concrete, that is.

HTH. If you are still having problems, I can take some flickr pictures that
will show it a little better than I can tell it.

Steve

On Sun, 12 Sep 2010 05:42:12 -0700, "Jon Danniken"
wrote:

Don Foreman wrote:

Looks like the slag is inaccessible because it's under the edge of the
joining piece. Instead of starting with a shoulder, weld that crack
shut first and then build it up.

Indeed it is under the edge. I still have yet to master welding up a gap,
which was why I was trying to weld up the shoulder, but perhaps this is a
good opportunity for me to learn it.

What rod and technique would you use for that?

Thanks,

Jon

I've not burned a single stick since I got a 220-volt MIG about a
decade ago so I'm working from memory here. Stick works just fine but
I'm in MN, prefer to work indoors when it's cold out and stick
requires a lot of ventilation to clear the smoke.

I'll definitely defer to SteveB as having far more experience than I,
but I would have used 6013 or 7014 when I made stuff like that using
stick. It looks like you're using 1/8" or 3/16" wall thickness square
tubing. I made a lot of stuff with that.

Technique: not having done it for a while, I'm not sure. I'd do a
quick experiment first on scrap. My guess is that I'd just weld it,
but I might change the rod angle or weave a bit if just running
straight wasn't giving me the fill I wanted. Watch the puddle, it'll
tell you. The main idea here is to melt that edge on first pass to
eliminate the overhanging ledge that can trap flux. Hm. Without firing
up a welder to check, I think I'd aim the rod more at the overhanging
edge and turn the heat down some, with the intent of getting fusion to
both pieces without blowing any holes.

If the resulting weld is a bit concave, that's easy to chip clean and
do another pass.

A couple of practice runs on scrap would quickly reveal what technique
will give you a sound and pretty weld in one pass. What works for me
might not work for you and conversely. Whatever works.

Welding up a gap is a very useful skill, not hard to learn with a bit
of practice and patience. I've heard that there are even those who
must weld holes shut that they've blown. Honest! G 7018 is a bit
runny for that sort of work, it's easier with 6013 or 7014.

I think 7018 is way overrated for simple fab jobs, particularly by us
amateurs. It's bitchy to strike, fussy about humidity, and it's kinda
runny so a challenge on vertical and overhead welds. I never used
much 7018, preferred 6013 and 7014. I've never had a weld fail in
service.

The most essential technique and discipline of welding seems to be the
hardest to learn and to inculcate: mind and manage the puddle.

Don Foreman wrote:
I think 7018 is way overrated for simple fab jobs, particularly by us
amateurs. It's bitchy to strike, fussy about humidity, and it's kinda
runny so a challenge on vertical and overhead welds. I never used
much 7018, preferred 6013 and 7014. I've never had a weld fail in
service.

All I have ever run before (what I cut my teeth with) is 6013. It's
predictable, and pretty easy for me to play with. 7014 I find to be almost
the same.

The most essential technique and discipline of welding seems to be the
hardest to learn and to inculcate: mind and manage the puddle.

It is only this year that I figured out not to stare at the arc when I am
welding, and that is probably the biggest thing to improve my technique.

Jon