TIG welding tubing

[frosty]

Hi all,

I'm a (almost) complete noobie when it comes to TIG welding. I bought a DC TIG (lift-arc start) and have a few questions....

How the heck do you get the nice "row of nickels" welds with a tig? I can weld ok without filler rod, and pretty badly using filler - I just bought a kg (a couple of pounds?) of steel rod and it seems ok.

I have a problem at the moment where I'm running a bead and trying to add filler in front of the puddle and it attaches itself where-ever it feels like, rather than where I put the rod - if I try to put the rod any closer it just gets melted.

Also, with the lift-arc TIG, there is no on/off switch, so to stop the arc you have to lift the thingy (what are they called? wand? handle?) away from the weld which makes it real ugly at the end... anyone had experience with one of these units that might be able to help? It's a pretty similar unit to the Maxstar 200DX

Also, getting back on topic (!) is there an easy way to cut tubing to make T junctions etc? I want to start practising my MIG and TIG on tube. Also, are there any techniques that people could share to make life easier?

Phew, that should give you something to think about!

Oh, and apologies for the "strange language" and lack of correct terms!

[dyn88]

welcome to the board. The thingy is called a torch. You may want to try a smaller diameter rod, it sounds like its not melting into the puddle quikly. What size is the rod? what are the settings on the machine?

[Teeps]

Making a T in tubing, well if your just making this for a structure, then your just adding a straight tube to the side of another tube? So the top of the T is a straight tube, and the lower leg of the T is going to be cut and welded.
If something is actually going to flow through the junction, then you'll need to cut a hole in the top leg before welding the bottom leg on, DOH!!!

So you need to cut the end of one tube, to fit the contour of the side if the tube you want to T-off of.

I haven't done this yet, but one easy way, seems that you could use a scribe or paint pen, or soap stone to mark the tube, at the end that you want to weld it. Using the end of another tube as a template, put the the tube perpendicular and against the end of the tube and mark both centerlines on a level surface.
Very important that the tube is clamped at 90 degree's, (for a T) you can also mark the template on the other side of the tube, if you can get the same angle when you move the template pipe to the other side. So the end of the tube, after you cut it should look like a C-shape and fit the contour of the tube you plan to weld it to.

Of course its not like tracing a circle on the side of a box, because the tube your making is round. You can roll the tube up, from centerline and mark it at the edge of the template tube as you roll it up.
Or you could also use a cardboard, or paper cut-out, a circle matching the outer diameter of the tube to be welded to (top of the T), then put that half circle against the tube (that is to be cut and welded) at the end of the tube. Fit the paper to the contour of the tube, and mark the tube, the half circle should be centered on the original centerline mark, and you can mark the centerline on the other side of the tube, and use the same paper template to mark the contour on th other side.

of course some guys can do this just by eyeballing things

Just some ideas!!

Good Luck!!!

Usually best to be conservative when cutting, and then grind a little more to fit right. Tack it at the right gap and go to town!!!

[stinkinlincoln]

Tig welding tubing is one of the most difficult fabrication skills there is!!!!
Making a consistent tig weld on any type of joint may take a considerable amount of practice. Mild steel is definitely the right material to start on. I recommend downloading the tig welding book from millerwelds.com or getting to your local supply place and getting a free tig handbook. These books will give you some good ideas about hand motion techniques. "Forward to heat, backup (slightly), add rod" is what my instructor always said. The torch should have a slight leading angle and the filler rod should be close to perpendicular with the torch. The filler should melt in the puddle not be melted in the arc.

Tube cope joints must be fit very tightly (virtually no gap) to produce high quality tig welds. Every factor (shielding gas, amperage, filler rod composition and size, tungsten size and composition......) is CRITICAL to good tig welds. A good hand book will help you out with those things too

There must be dozen different ways to cope pipe and tube. If you want to spend some big bucks, search the internet for "pipe notcher" or "pipe coper". if you have access to a lathe or mill you can get a cutter with the same diameter as your tubing, use a little "clamping savvy" and make excellent fit-ups that way. You can also make your own templates (find a book on pipe layout techniques) , however that can be an involved process. Welding supply stores also sell pre-made templates you can use to mark the pipe and cut with plas or acetylene torch.

For specific help, it would be good to list all your settings and sizes: base metal thickness, pipe size, filler rod comp., amps.......
Pictures would also help with diagnosis.

Bracing your hands against the pipe so you can be very steady is important. Practicing the motions without the arc going can help. Get comfortable, stay comfortable. I would practice on flat sheet fillet joints first. Not everything a book tells you is right.

Practice, Patience, Practice, PATIENCE, Practice

Oh yeah be sure your not using a lincoln welder

[tomasharvey]

Tig

TIG welding is one of those things that if you do not practice until it's second nature (I am getting good but not perfect) it will be a tough process. I have books and charts but I think the best possible learning tool is to find someone to watch or take a class. Adding filler material to the puddle is an art form. As far as I am concerned you don't learn this from a book. Reference material is great for cup sizes, tungsten types, amperage etc. If you can convince someone to watch they can probably have you running beautiful flat beads in no time.

Keep practicing. Find someone you can watch. As mentioned before, tubing is extremely difficult to master. You are welding in all angles and direction while trying to keep a consistant bead. A tune notcher is a good investment. Rent one if it's a one time deal.

Good luck and keep running beads. Make yourself run vertical and other positions other than flat. Brace your torch hand and HAVE FUN!

[frosty]

hey guys

thanks for all the advice - strangely, I was thinking about my technique last night and wondered if I should be backing up the torch before applying the filler rod. Sounds like that is the way to go - which would explain why my filler rod melts before even getting to the puddle!!

I will practise some more tonight!

[cleaver]

Hi,

I just stated tigging too for the past few weeks and boy its fun!

I already am ok with doing a bead on flat stuff making butt joints, lap joints, and t-joints...basically I still need more practice but im ok on flat metal!

Today I tried tubing. I went to the scrap yard and got myself a 4.5feet stainless tubing 16ga 2" size. I cut a foot and cut it to 3" lenghts...I used a hacksaw cutting them so its not straight (dunno if this info will be useful). I understand that welding stainless requires back purging, but I can still weld stainless without back purging anyways right? Its just for practice...

Anyways, its really frustrating welding a tube, because tacking the tubes together is already hard for me. I keep burning though...so I cant even start a bead! hehehe...So I need help and any advice, on how to TACK and weld a bead...

My machine is a Miller Maxstar 152 with the Snap Start II HF...im using a 1/16" 2% red band tungsten with gas lens and 1/16" stainless filler. I didnt really even get to use the filler because I cant even start a bead! hahaha..I set the machine at around 60 amps, but the pedal was not even all the way down!

Thanks in advance..and much appricated..

best regards,
cleaver

[2gofaster]

Thin wall tubing is very frustrating to learn to tig. When I was learning, I'd make 3 or 4 small mig tacks to hold it together, then I'd make tig tacks beside them and grind off the mig beads. Especially on the 16 gauge and thinner tubing, I won't try and start the puddle on the joint. I'll start it off to the side on one of the pieces and then walk the puddle over into the joint once it's started which seems to keep me from burning through as often. If I were to do it all over again, I'd have started on some .118 carbon steel tubing or .083 4130 tubing instead of the thin wall stainless. Chromoly is really nice to learn on since it welds so nicely. You can really get a feel for the hand movements you need without worrying about burning through so easily and the puddle flows very nicely.

[cleaver]

hey,

Well I tried it again today and your right! it is very frustating! hahaha...so I tried something else, Basically I tried the method of starting the puddle on the side and drag it over to the joint. It would still burn though so I did something different. I used a filler as a tack and it works! hahaha....basically I would melt the filler and put a dab on the joint and it would take it nicely! I will still practice some more but this right now works best for me...

thanks for the help..

cleaver

[eric75]

Most of the tubing fit-ups I do are free hand. The tool of choice is a handheld die grinder with a cut off wheel. I cut the tube to length, then put two mitered cuts in the end. From that point it's just a small amount of material to grind off for a near perfect fit. For this last step you would ideally use a sanding drum in another die grinder, but the cut off wheel works OK if you have a steady hand. If you have really good eyes this technique will work for tubing up to 2" O.D.
Attached is a picture of what I'm talking about.
I started using this method because the hole saw based notchers in our shop were too sloppy for .049" wall tubing. Always ended up freehanding to clean up the bad fit anyways.

Another way to practice on tubing is miter joints (like a picture frame). It is less preparation time and still teaches you the body english required for tubing.

When practicing on tubing, I use magnets or masking tape to hold the pieces together. The masking tape leaves a residue that is easier to wipe off than duct tape or electrical tape. I know it sounds hack, but sometimes there's no other way.

Not to say you should build roll cages like this, but it is good to practice filling gaps across fit ups that are less than ideal. It will give you a real sense of what you can and can't do. Challenging yourself when practicing makes good fit ups easy to weld.

[revpol]

First off I don't believe teaching a newbee to dip (stacked dimes) A newbee has enough problems just controlling the arc length, rod in one hand,tortch in the other, finding a comfortable position to even weld on a flat plate for any distance. What I've found best to do is teach a newbee to leave the wire in the puddle, free handing, teach them arc length and how to control the puddle first. What the wandering eye (or white dot) is and what to do with it. Tortch angle and wire angle and how to position themselves. After they learn this then I teach them to stack welds, walk the cup ect. For right now you don't even really know what your puddle is going to do. It takes a bit of practice to tig but once you get the hang of it you'll really enjoy this process. revpol

[revpol]

If you are having problems with the tacking a little trick I've used is to set your machine to weld whatever size wire you're going to use then grab a piece of wire at least 1 dia. size larger use this wire for your tacks. Starting off to the side is okay but you may drag in contaminents in your tacks. And they don't go away and you won't burn them out you'll have to grind them out. revpol