Slag on my shoulder

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/img190/2696/slagshoulder.jpg
Any ideas as to how I can remedy this situation?
Thanks,
Jon
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snipped-for-privacy@yahSPAMhoo.com says...

You're almost always gonna have some slag in the root of many fillet welds, no matter what you do. Nature of the beast. If it really bothers you, try one of them dremel tools or using a sharp pick to chip it out.
Your fillet is only going on the outside of the tubing, but the flux covering the rod is melted and mixed with the filler metal. Your fillet weld has a root and a face, of which the face will collect most of the slag. Some little amount will stay in the root. Not a problem. You should be able to burn it out with the next weld pass, too, after looking at your photo.
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Tin Lizzie
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TinLizziedl wrote:

Thanks, I appreciate that. It isn't a large amount, just kind of bugs me to weld over knowing it will be in there. Wouldn't be a problem on this project, but if it was a trailer, I'd probably not want it in there.
Jon
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snipped-for-privacy@yahSPAMhoo.com says...

Also, you can grind it open a bit to get rid of slag and to help ensure getting good fusion. You may not want to simply weld over that slag and try to burn it out as you go, cause that may leave a void in the weld if it doesn't work.
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IMHO, you are running it too cold, aiming it too much to the larger piece, and not attaining a puddle that will flow over to the thin walled tube. Is this something you can move into the flat position? Turn up the heat a little, it looks like you are aiming at the big piece with a little too much downward angle, and try go create a puddle that you keep entirely on the big piece, otherwise if you wander up, you'll just blow a hole. Try to get it to "flow" up to the thin piece, meaning the bottom 2/3rds of the C of your puddle is going to be on the thick piece. Steady movement no whipping. The angle of the rod should be at least perpendicular, and I'd try it even a little bit below that so that the tip of your rod is pointed upward.
Think of it as squeezing honey out of a bottle. How would you do that to get it to go where you want?
HTH.
Steve
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On Sep 11, 8:11 pm, "Steve B" wrote:

Thanks Steve, it does indeed. I was also running it too slow (experimenting), but today I bumped it up 10A, and it seemed to flow a lot better.
I played around with two different techniques today, first I used a 3/32" 6011 rod for the root, which added a difficulty as I have never been able to run that rod before (nor is rod manipulation my strong suit). It's not close to perfect, but it's a lot better than when I started out:
http://img545.imageshack.us/img545/1507/shoulderroot6011.jpg
It looks like there is some slag trapped within some of the "Cs", I'm guessing that is the result of inconsistent technique.
The other thing I played around with was using the 1/8" 7018AC, but instead of focusing it on the shoulder, I just kind of aimed it into the gap, keeping at a speed that just melted the outside edge of the top piece:
http://img291.imageshack.us/img291/5386/shoulderroot7018.jpg
That actually seemed to work out okay, but I don't know if that technique is one that produces sound welds.
Jon
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Jon, try this experiment. Do a 2" length of 7018 in the flat position. Let it cool Inspect it, but don't chip off any slag. Notice how the slag covers the weld, just like a scab covers our cuts.
Now, do another 2" weld, and turn on the end and do another so as to cut into the first weld by about 1/4 of the width of the weld.
Notice that the molten pool will melt away the previous slag, and even be able to lay down a deposit of solid metal UNDER IT.
What you are seeing in your 6011 pass is not important. A subsequent cover pass of 7018, or even another one with 6011 will be able to melt all the slag inclusions and float them up to the top to be captured in the slag cap.
This is a very important thing, to know that you can have slag in the root or first pass, and be able to "boil" it to the top, and have it join the slag cap instead of the base metal. Your 6011 pass there does not look bad, that's just the way a smaller rod with less iron powder in the coating ends up looking. That's why you can whip it in and out where you can't do that with an iron powder rod.
Have you ever welded with some of the HUGE FATTY iron powder rods? NO movement except forward. Maybe a little circular, but you want to keep the molten crucible fluid and boil out impurities and slag inclusions from previous passes. You can actually see them boil to top, them being grey bits that go fluid and then solidify.
You're getting there. Slag inclusions are a bad thing for any weld, but they are not the end all be all that causes a weld to fail or a test to fail. They can be burned up on the next pass, and all of it melted into a very nice looking final cover or weave pass.
Don't obsess over the slag. Try to get out all you can, and to improve your whipping, weaving, or figure eighting so you get the minimum amount, but if there is some, not to worry, mate. Just boil it out with the cover pass. Rust, paint, and slag can be boiled out, it's just learning how to do it, and what it looks like. What it looks like is grey particles coming out of your weld and floating off into the flux.
The ease of which the flux peels off indicates whether your weld is too hot or too cold with 7018. On a proper 7018 weld, if the heat is right, the slag will peel off like a banana peel peeling backwards as it dries in the sun. You can run the uncoated end of a rod along the weld, and clean it up very well. Slag will hardly stick, and that's where all the rust, slag, and paint are trapped because it is so much lighter than the deposited metal.
HTH.
This is what I want to film some welding videos and sell them for.
HOW TO WELD BETTER WITH XXXX (YOU NAME THE ROD) IN ONE HOUR!
As you know, it's the final weld that counts, and even that can be ground down to look passable, slag inclusions and all. So long as it is not a critical weld that is supporting humans, holding pressure, or holding a trailer on, it will do. Of course, it is nice to have a 100% good weld there, too, and just as easy.
From what I can see in your pictures, you're whipping out of the puddle a little too soon, and on the 7018, you should not have the "stack of dimes" lines like the other rods, indicating you are having a little too much movement.
The most difficult thing for 7018 is to let it make a puddle, wait for it to get to the point where it is bordering on collapse, then moving on. Slow steady motion with all the angles set before you get started, then just draw a straight line.
It's like a car. You can understand a lot about batteries, alternators, valves, pistons, timing, oil sumps, and all that other, but until you put it all together and understand how it comes together to perform in symphony, you aren't a real mechanic.
Will get out there soon and try to create the same thing you did, and take some pictures.
HTH
Steve
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Steve B wrote:

Hey, cool, that was a neat experiment. Not only did the second weld melt of the (rather thick) slag coating, but the resulting weld underneath it was as smooth as a thing that is really smooth. Looked like a DC pass it was so smooth.

Aye, this is currently practice pieces for my current project, which isn't critical at all. Still, if I'm going to take the time to learn this, I'd like to get as good as I can for the day when I practice on something that for a more critical project.

Thanks Steve, that's a help. Manipulation isn't my strong suit, but I've come a long way in the last few sessions.
Jon
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The only concern I would have with either pictured weld is the undercut along that top toe. It looks like you tend to move a little too fast, trying to drag the puddle along. Slow down a little and let the puddle fill in as you gently let it flow along the joint.
That's one of the hardest things to learn- you're not in a race to the end of the joint, your goal is just to lay down a good weld.
I know you don't want to blow a hole through the tube so you're moving quicker, but try to go just a hint slower and allow that puddle to fill in along the toes of the weld. You'll get less or no undercut, which will give you a much stronger weld.
In case you are unfamiliar with all our welder terminology, undercut is where the weld cuts into the base material, but does not fill in the void created, leaving a sharp notch and / or dished out sections on the edge of the weld (the toes of the weld). This undercut means the joint may have sharp irregularities (notches) and underfill (dished out spots). These two conditions cause weakness at the edges of the weld as stresses flow along the pieces. (Google "Stress Riser")
If the joint to be welded is in a horizontal position, try giving your rod a little motion, just a tiny wiggle, up and down. No big or dramatic motions, it's more like you're thinking about the motion more than you're actually moving. Just that teeny, tiny motion, not even as big as the rod is wide, will cause the puddle to fill in on the toes of your weld. Keep the center of the puddle centered on where you want it, just use that tiny motion to tie in the toes.
Remember! It's not a footrace! You won't get any points for finishing fastest or firstest if the joint breaks cause of undercut toes.
--
Tin Lizzie
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TinLizziedl wrote:

I definitely noticed the undercut. The problem I am having on this isn't blowing through (the 1/8" rod and 3/16" material is helping in that respect), but I find that if I go too slowly the resulting weld is a big gob that looks like it just sits on top. There is a sweet-spot I hit sometimes, though, which is when I get the speed and angles all dialed in right, but I still don't have a consistent handle on that.
It can be frustrating making a really good looking weld, but being unable to repeat it.

Thanks, I'll give that a shot. All of these are horizontal welds, with the added fun of being done with the target materials on a concrete block eight inches off of the concrete floor in my carport. As a bonus, the stinger lead "catches" on the floor, adding an additional variable. I'm thinking about putting a small chunk of a plastic (teflon or formica) on the floor to let the lead slide across it a little smoother.
Jon
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On Mon, 13 Sep 2010 20:22:09 -0700, "Jon Danniken"

So the next project will be a welding table? I'm too old to enjoy welding on the floor if I can keep from it.
I'm planning on making heavy duty folding sawhorses for the new shop, and a piece of 1/2" plate to hoist on top, probably have a single threaded hole in the center for a shoulder eyebolt. Then I can stack stuff out of the way for other projects.
Pete Keillor
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Pete Keillor wrote:

Boy, if I had the room I sure would.
I might splurge and put the current project up on two concrete blocks, putting it 16" off of the ground instead of 8".
I like your eyebolt table idea, though. That'd be a real space saver.
Jon
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snip

This is a common problem more easily and simply (KISS principal) solved by routing the cable over your opposite shoulder, and behind or in front of your body.
Alternatively, some people tape a small hook on the cable which they hook to their waist. Often when welding pipe or fabricating at waist height it is easy to just put a loop of cable over the work, leaving some to hang down but not so much as to drag on the floor. This keeps your stinger cable off the floor and as an added bonus will make it feel lighter as there will be little cable hanging under your hand.
Some weldors find that wrapping their cable(s) around wide flange beams can reduce arc blow when welding with big electrodes and high heat.
This same technique will also make huge improvements when OA cutting.
Good luck, YMMV.
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I like a 6' piece of smaller cable that is connected to the main lead with twist on sockets.
Steve
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I keep a light whip for most work/small rods, and a heavy one for big jobs/rods where heat build-up may be a problem. IMHE, light cable whips often overheat and fail right at the rod holder as that is where most of the flexing and heating occurs, they need to be shortened periodically and keeping a spare lets me keep on working if I have a failure at a bad time.
I also use a smaller whip hose on my OA torch for all the same reasons.
I think we would see these setups on most personal rigs.
Just my .02, YMMV
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PS, IMHE the most common point of failure of OA whips is also right next to the torch, and these also require periodic shortening. I keep some small screw type hose clamps handy for emergency repairs.
Good luck, YMMV
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Had one happen yesterday. Now I have an excuse to go buy a crimping tool and crimps.
Steve
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After I hit SEND, I realized that the small whip does not work on larger rods. duh. But I used to do a lot of small 3/32" rods in the field for ornamental metal field fit and repair, and it sure was easier than a big one. Still, I'd drape it over my shoulders to make it lighter, and less pull on my welding hand.
Steve
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snipped-for-privacy@hotmail.com says...

I've got the standard 6' stinger lead issued by the shipyard toolrooms (heavy, but good for half a bazillion amps) and a not-so-standard navy- issue emergency repair stinger lead that I've cut down from 50' to 15'. That one is sweet, and is perfect for 3/32" rod. I use it a lot when cladding overhead, as it weighs 1/3 less than my regular stinger.
I loop it over my shoulders or use a piece of string to tie it up so I'm not holding up the full weight.
For arc-blow, I've got some powerful magnets or I'll use a grounding clip lead (sizable spring clamps on each end) to help redirect those funky currents.
--
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\

First time I saw arc blow, I was helping a couple of welders offshore. I was a crane operator. After some failed attempts due to severe arc blow, the one guy said, "Just wrap the lead around the work a few times, and lets try that."
It worked great, and the second welder (and me) learned something.
Steve
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