Welding Tips and Tricks

Hey yall,

I need some help, I'm teaching myself to tig weld again after many years and limited weld time when I did it before
What I'm working on right now is some thin gauge 300 series SS, I'm trying to weld 18ga to 16ga at something between a T-joint and lap joint as in at a angle roughly 45° /

My rig is a HTP Invertig 221, 1/16" 2% lanth with sharp point, have tried 1/16" filler and .030" filler, both ER308L, I can fusion weld the 18ga at about 45 amps set up in the rule of 33, but when I try to weld my project together I wind up melting off the edge of the 18ga before I can get the 16ga to melt

Please help

Are you pointing the tungsten toward the thicker piece?

You mention lap joint so are there small flanges on the backside of the internal supports that are flat against the v piece? hard to tell in the photo.

If so Id clamp them tight, use a piece of alum, copper or bronze as a backer and weld a nice lap joint, stitching it is a few places, or if the joint is very tight you could fusion tack. If there is no flange to clamp to, and its a fillet weld that will be a little tougher, still need to find a way to clamp the pieces together if at all possible or youll be fighting getting a fluid puddle. Id recommend not pulsing a fillet joint and using a small diameter filler wire, like .030" or .035", even mig wire will work 308L.

Your settings aren't too far off if your dead set on pulsing, I weld a lot of 16g at 55-60amps, 75% peak, 25% background, 10pps, 1/16" tung, #8 cup, 15cfh this can be done without pulsing though with a standard foot pedal. The difference in thickness is only .012" nominal so it shouldn't be an issue if torch angle is good and you keep a nice tight arc length.

Regardless to make it easier on yourself Id rotate it and put the outside surface flat against a table so your welding a flat fillet or lap joint, then your wont have to weld semi vertical since its been awhile.

Big gear head, yes I have tried to stay more on the thicker piece

Rick_H
No, there is no lip for a lap joint, what I was trying to describe is the fact that it's not a 90° T joint, as the pieces inside the angle are leaned at about a 45° or so, dunno what kind of joint that is really considered

The 308L I have that is .030" is mig wire
Only thing that sucks about that is the curve is killing my feeding, Ima have to get used to that

I'm not dead set on anything other than figuring out how to weld this up, so I'm willing to pulse, not pulse, whatever

Thanks yall

You can straighten that mig wire to make it feed easier.

There are many ways to do it but I take a piece of brake line bend it to a S-curve. Just tight enough so you can squeeze the wire through. Chuck it in a cordless drill, spin it and pull through the pipe. Will come out nearly dead straight.

Clamp one end of a length of mig wire in a vise, grab the other end and pull until you feel the wire give slightly, it will then be straight.

Thanks, I'll try those tips

Another thing I would add on staying more directed to the thicker piece is to kinda block the heat with the wire and just let the heat fan it into the thinner piece. It's going to be a "tough" weld but there is a magic spot where you can motor on and it'll be OK.

How's it go? One trick I use to clamp awkward shapes is I'll wrap a rachet strap around it to cinch it tight, then I'll use a backer (alum or brass) and a deep throated Irwin clamp.

Your work bench is stressing me out by the way I think what you need is a jig for welding that. A couple big blocks of aluminum so the piece sets up against it flat at 90 degrees with some fingers coming down to hold the cross braces in place. If I had to weld a bunch of those I'd fab a jig.

SprayBomb - any luck?

Are you using a foot pedal? If so - and you may already know this - adjust the amperage at the machine so that the total range available at the foot pedal is small - say 20% on either side of the estimated needed amperage. A tiny movement of the foot pedal if the machine is adjusted for 150 amps is a bunch of amps at the weld puddle, and it's hard to modulate that when welding thin stock.

If the pieces are not totally straight and tight to each other, it's very difficult to weld them - even to tack them. I often start the weld puddle on the thicker stock - and especially on the flat rather than the edge piece. Then, after the puddle is forming, add filler rod and sweep the puddle over to include the edge piece. Then advance the puddle from there. A very tight arc length is critical on welding thin material.

Hope these comments help.

One thing I've seen with new TIG welders is they are too careful ( too low amps) and end up burning back the edges of their parts. Get yourself a big chunk of aluminum flatbar clamped to the outside. Stab the peddle hot enough to get it to jump and move like a bat out of hell.

TIGHT as possible, clamp aluminum or copper backing bars behind both edges of the weld, keep a very tight arc, and use lay wire.

I've bookmarked this thread, I recently failed a welding test on SS trying to get a job at a really big architectural product company that needed some TIG welders. I'm just a self-taught welder and a TIG newbie so I knew my chances were slim but I figured I'd give it a try anyway. They deal with aluminum and stainless TIG only, and after passing some fairly easy (and sometimes silly) written tests the hard part came as I tried (and failed) at not making a fool of myself. First was the aluminum T-joint fillet, though it was ugly they felt I could be taught better so I managed to pass that portion of the test. At this point I was psyched at the prospect of getting a decent job and making better money and working in a place that nice and practicing welding all day long.Then they gave me the same T-joint, but in SS... where I miserably failed. They started the weld for me, an impossibly small bead, and asked me to continue it. Half my problem was I couldn't even see what I was doing with such a small bead, I needed stronger glasses for it (I only started wearing glasses recently in my old age, and have been using the strongest cheap $20 reading glasses I can find at the local Rite-Aid pharmacy, which are good for most welding but for this was totally inadequate). The other half of the problem was they had me use an .035 filler rod, more like a filler hair, I didn't even know how to hold it it was so thin. And I could not for the life of me even start a puddle without blowing through. I tried lowering the amps, but to no avail. They even gave me 3 tries after destroying each piece. I was so embarrassed. So I'm eager to hear how it goes for you Spraybomb! Good luck!

Yeah, the eyes will betray you...

I now have eye-care insurance and I USE it. I wear bifocals and it makes a difference. I think I'm already due for a new prescription, as I did 16ga to 11ga and 11-11ga stainless with .035 filler just yesterday. (6 outside corners and a butt joint.) I found I had to keep my head back around 18" to be in focus, but the #10 fixed lens wanted me to be 6" from that 11-15 Amp weld for it to be bright enough to see what I was doing. It came out acceptable, but I did it as much on feel/experience as what I could actually see.

Steve S

Otto Nobedder wrote:Yeah, the eyes will betray you...

I now have eye-care insurance and I USE it. I wear bifocals and it makes a difference. I think I'm already due for a new prescription, as I did 16ga to 11ga and 11-11ga stainless with .035 filler just yesterday. (6 outside corners and a butt joint.) I found I had to keep my head back around 18" to be in focus, but the #10 fixed lens wanted me to be 6" from that 11-15 Amp weld for it to be bright enough to see what I was doing. It came out acceptable, but I did it as much on feel/experience as what I could actually see.

Steve S

yeah, one day I'll have insurance... only insurance I can afford at the moment is my basic car liability insurance, so it's cheap glasses for now. At least with cheap glasses, I don't get too upset when I step on them, I have a bad habit of breaking glasses (and anything that's delicate). So don't ever hand me your infant baby, I will drop it. lol.

Yeah, one thing I've learned about welding, if you can't see what you're doing, stop, it's just gonna be ugly (at least for me).

I was a DOD aircraft certified welder for 9 1/2 years in a jet engine plant. I had to pass a weld test every 6 months on inco 625 and L605 in flat, vertical, horizontal .030 and .060 and T fillet with a .060 base and a .045 top 8 inches long. Zero burn through, no back purge and no pipeline on the T. I know what you mean about the small bead. I was 22 when I started that job and my eyes were still good. I have to use glasses now, but I don't have to pass that test anymore.

Bigben wrote:One thing I've seen with new TIG welders is they are too careful ( too low amps) and end up burning back the edges of their parts. Get yourself a big chunk of aluminum flatbar clamped to the outside. Stab the peddle hot enough to get it to jump and move like a bat out of hell.

THIS. Unless you have backing bars, or found the holy-grail for the pulse settings, it's far too easy to blow through thin SS, done it myself a bunch of times, LOL. Of course, never learn how to tig thin SS on the actual part, that's the worst thing. You need dedicated practice pieces and learn to bump up the power initially to get a puddle to form a good tack, and not blow a hole because you sat there feeding 10A for like 5min straight thinking a nice tiny puddle will form because the amperage is so low. Tight fit-up is a must.

I've kinda got myself in aa habit if using the filler to do the work on thin steel or thin to thick. Because the edge melts so much easier if I direct it more towards the bottom and wash it into the top with the filler and from there its a breeze. It's just getting the puddle going without blowing through till you get a little reinforcement on there.

While the discussion on achieving this fillet weld has been interesting unless there is some reason it has to be done this way the obvious solution is to turn a 90degree flange on the ends of the divider pieces ( need only be 1/4" or so wide ) then you have a lap joint which would weld a treat without filler - especially if positioned to weld downhill - far easier & almost certainly if this part whatever it's for was being produced commercially that's how it would be done - though possibly spot welded for speed.