Welding How-to Advice

Ok, long story but I started the current project with a Harbor Freight Mig welder. 2 days, 10 inches of bead and 8 hours of maintenance
later I got pissed and visited the local welding emporium, where they fixed me up with a Lincoln SP-135+ and a cart for a good price.
Like night and day. Lincoln units are highly recommended for those considering buying. Harbor Freight units are not.
Now to the sought-for advice: The situation is a lot of joints involving a vertical piece sitting on a horizontal piece. It seems that when I strike the arc, it will jump to either the horizontal surface, or the vertical surface, but not both, so running the puddle in the corner where the two meet is not possible.
I'm no welder by any means. Just a home hack. But I've done a little stick welding and never encountered this problem.
I've been dealing with it by running one bead on each surface as close to the corner as I can get it, and then running a third bead on top of those to tie it all together.
Is this anywhere close to correct, or normal?
If it matters I'm using .024 wire and 75% argon, on the advice of the local shop.
The project is a table, using 2-1/2" square 1/8" wall steel tube for frame and legs. 2-1/2" is probably overkill for the purpose (table saw outfeed) but its what I had in the pile, for free, so I'm using it.
TIA
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ground both pieces *very* well, grind them, make sure ground clamp is clean..
I have run into situations where you had to weld a bead on each surface, and one final connecting bead.
Can you post pics of your setup?
Rich
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On 24 Jun 2005 13:59:42 -0700, snipped-for-privacy@gmail.com wrote:

I just finished running some test beads. Ground clamp is clean, metal is clean, but 2nd piece wasnt clamped to first, just sitting there. Will re-try tomorrow with your suggestions and see what happens. Will get some pics if I can remember to take the camera with me.
Did i mention this stuff is galvanized? I've been grinding it off some joints, not on others, result seems to be the same either way. Yep I've got a big ol' 30" floor fan running air across the area where I'm working.
Just running a bead on a flat piece, it goes where I point it and I get good penetration.
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That's OK. I never connected the second piece to ground. If it is halfway clean, it will have contact. After the first little weld, contact is perfect.

It should work with the thin wire too. But your diameter is more for body work.

No!
Grind it off on all. The zinc is nasty healthwise and prevents good joints.

don't blow away the gas! Try it without fan.
Nick
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wrote:

Sounds like arc blow; the path of the arc is influenced by local magnetic fields. Try moving the ground clamp to various locations to change the current distribution in the workpieces. I have not had this problem with my similar Lincoln.
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On Fri, 24 Jun 2005 16:45:06 -0500, Don Foreman

Afterthought: you really shouldn't have much arclength with MIG at that current level. Try going to .030 wire. Maybe your smaller wire is burning back too far.
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On Fri, 24 Jun 2005 16:58:50 -0500, Don Foreman

Ok I'll try that working on the ground location. The wire burning back also sounds like a possibility altho I've had no problem keeping the arc about 3/8" out from the tip as recommended by the book. I'll have to make a trip to the welding place to get some .030 wire but I'll do it and let ya know how it works out.
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Just as a data point... I'm no welding expert either, but I had a SP 135+ and never experienced this problem.
Peter

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0,8mm would be a bit better, but it should work.

what amperage (well I know, MAG is with voltage) do you use? Not connecting to both pieces sounds like not enough current. Do the fillets look like a worm? At what distance (nozzle / workpiece) do you hold the nozzle?
Nick
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On Sat, 25 Jun 2005 00:06:04 +0200, snipped-for-privacy@gmx.de (Nick Mller) wrote:

I dont know what the amperage is. I'm running the machine about in the center of its adjustment. If I go much higher or lower I cant seem to maintain a consistent arc. Nozzle to workpiece is as close to 3/8" as I can hold it.
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If you go up with the setting, does the wire feed also increase automaticly? I _guess_ no. Go up with the voltage and play with wire feed. There is really nothing like "nonconsistent arc with too much current". Disregarding that you will burn holes. :-)

10 times the wire diameter is 'bout right. So this is OK.
Nick
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On Sat, 25 Jun 2005 10:29:41 +0200, snipped-for-privacy@gmx.de (Nick Mller) wrote:

Not automatic but increased voltage/feed makes sense after I think about it for a bit.

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I mean, if you go up with the voltage, do you have to readjust feed (more than just a tad)? Are you also aware, that 0,6mm wire needs _double_ the feed rate than a 0,8mm wire? Why? the sectional area of 0,6mm is about half of 0,8mm. to get the same "pound per minute of wire", it takes double the feed rate.
I'm still convinced, that you will get it working if you play with the feed. A 0,6mm wire is not so common. Most MAGs are set for 0,8 or 1,0mm wire. You have to adjust (and should be able).
Also, could you describe how the arc looks? Is it long (clearly above 2mm)? How does it sound? A hard, more _fast_ hammering sound, or buzzing and irregular? Does the wire get frequently stuck in the wire-nozzle?
Nick
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Congratulations on getting a Lincoln. The 135 is an outstanding machine WITHIN ITS LIMITATIONS. (explanation to follow)

HF units are ****.

What you need to do is aim the wire to the piece that is horizontal. Have the heat turned up high. Pause to develop a puddle. Let the puddle flow over to the vertical piece. There is a world of difference between pulling the wire and pushing it. There is also a world of difference in the angle at which you attack the metal.
Now, for what I stated above. Turn up the heat. Use bigger wire. BUT, then you approach the limitations of your machine, which is the duty cycle. That is how much welding you can do before you have to let the thing cool off. Some are very low, like 20%, meaning you have to let it cool down four times as long as you weld.

You may get "cold lap" which is one layer on each other, and not fused together. You need to turn up the heat and get bigger wire, and watch for it to dig a crater, and then fill it up, letting it overflow, and being pushed towards the vertical piece.

It matters big time. Use .030 wire.

You can safely weld this metal with bigger wire, higher heat, higher wire speed, and the "wash" technique. Just weld a bit, and let your machine cool off. It is good anyway to do intermittent welds to keep down the distortion. Do circles to get a bigger puddle, and watch that your heat is high enough that you can see it slightly eat the base metal away at the front of the crucible.
Steve, a weldor since 1974, 6 topside certs, and underwater welding and cutting experience, former State of Nevada Licensed Steel Erection Contractor
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On 24 Jun 2005 13:59:42 -0700, snipped-for-privacy@gmail.com wrote:
.>Did i mention this stuff is galvanized? I've been grinding it off

Be careful not to blow away your shielding gas with that fan......
Jeff
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On Fri, 24 Jun 2005 21:15:55 -0400, "Jeff Sellers"

Point taken. I dont think its happening but I'll definitely watch for it. I've done a couple of test beads with the gas off (duh moments) and there's a real visible difference. But I hadn't considered this. Thanks for the heads up.
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On Fri, 24 Jun 2005 21:15:55 -0400, "Jeff Sellers"

Several mentioned this and to clarify: It's a 3-speed fan, on low. Both front and back shop doors are open. Fan is about twenty feet from the work and is moving air from the back door towards the front at a relatively low rate. I don't think its bothering the gas flow but will certainly make sure of that.
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But you already know how a weld without gas looks like. :-)) If you don't have enough gas, you will have tiny bubbles in the weld. Same as with dirt (grease, oil, etc.).
Get rid of the zinc until you know that you can weld and how to set up your MAG. You need a lot of heat to vaporize that sh*t and it makes controlling the puddle _much_ harder.
Nick
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On Fri, 24 Jun 2005 16:18:56 -0700, "SteveB"

Thanks Steve. General concensus is i need bigger wire and Im off tomorrow to make that purchase. More heat is available and I just have to play with it to find what works.
At what gage or thickness would you use the 024 over the 030? I've got two spools of this stuff and I'd hate to think its useless :)
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Should be good for thin sheetmetal work where you do not need, nor want a lot of heat, and you do not have large gaps, nor want a large bead.
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Anthony

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