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.