Dan W

I'm learning to tig stainless so I can weld up a set of turbo headers. Take a look at these photos... feedback is apreciated.

These are 1 3/4" 16 gauge 321 stainless. I cut them with a band saw and used a belt sander to true up the ends then deburred with a sanding roll on a dremmel. I didn't backfill and I didn't add any filler. I didn't attempt to clean the metal around the weld with acetone or anything.

I welded them using a miller dynasty 200dx dcen with 100 amps on the dial, 100% argon at 20scfm.

Note the black crusties on the inside. I was looking for more penetration so I brought up the heat a little and thats the result. Do I need to clean it better or backfill to prevent that? What exactly am I looking for on the back side as far as penetration goes?

Dan W

The inside

ghettocruiser

iTrader: (4)

Doesnt look too bad man. As long as its sealing good, you'll be ok with that. Just practice some more, and try to be more consistant with your bead (smoother). Are you resting your arms while welding? or are you holding your hands/arms up while you are going. I find the better my arms are rested, and the more comfy I am, the better. For MIG or any kind of welding.

Here are a couple pics just for reference. This is all stainless except for the flange rings.







For headers, Ide just try to keep the beads as neat as you can, but most importantly, make sure they are sealing. You should be fine... Looks like you have practiced a good bit, and just need to fine tune yourself.

J.

Sonix

iTrader: (1)

Scrub it a bit with scotchbrite and acetone if you want it to look a little cleaner. If the metal is thick you can backfill with the argon, but that's mostly to prevent "sugaring" on the inside.
the inside of yours looks ok, so I wouldn't lose sleep over it.

Dan W

I was playing with several different techniques and different amounts of heat when I made the weld so it doesnt look very consistant there.... I can make it look better.

Supporting hands, arms and torch I think is the most challenging part. I'm only able to weld about 1/6th of the way around before I need to stop and reposition. I wonder if theres something I can do with my technique to go further between stops. It seems that if I try to go too far I run into a bad torch angle, visibility problems or in the attempt to move my arm up and around I end up with much less control of the torch and the weld starts to look like crap.

I've been playing with mild steel for a while now... trying to build up my skills to the point where I'm not worried about trashing a bunch of expensive stainless bends. These are some of my first welds on stainless.
Its actually not too hard with good fitting joints.

That one that you did with the flange, were you spinning that on the table while you were welding it? I can't really see any spots in it where you stopped and restarted. Do you push or pull? It seemed like pushing was giving me better visibility without any downsides.

ghettocruiser

iTrader: (4)

On the flange pieces, I did start/stop. I had some help because it was only like my 3rd time tig welding. I used a machine shop's set up...they were nice enough to let me come in and use their machines.

For the flange, it was laying flat on a piece of steel, and it was clamped. I needed to be careful beacuse those flanges dont use gaskets...so that surface had to stay perfectly flat and uniform. Oh and I pushed on the flanges if I remember correctly.

For the rest of the pipe, I sort of stood it up, and just went around. I was able to find positions that allowed me to atleast have my elbows planted on the table. Welding butted together pipe is alittle different than fillet welding like I did on the flanges. Its harder in my opinion. On the flange you can sweep it and its easier to see a start stop point.

J.

KBcobra

sry to hijack what kind of filler metal do you use?

jwscab

looks pretty good for learning how to weld. Stainless is nice to work with, except it can be 'burnt' with too much heat. the second set of pics by ghettocruiser with the tubing is a little hot, you can see the welds are dull gray, probably won't matter, but just pointing it out.

couple of tips to help you out as you practice:

set your welding area up so that you have a nice rest for your torch hand. block of wood, other misc pipe, whatever you have on hand to help you get comfortable. this has been mentioned already.

if you are using this for a turbo manifold, I would suggest using a back gas to help prevent bad sugaring, which could break off into the turbine.

if you need to use filler, you can simply stick it in the groove, and work the torch to fill in the weld, no need to do the 'dab' technique.

make sure to remember that as you get towards the end of your weld, the material will be hotter, and you need to use less current, otherwise you risk burning through.

Dan W

I didn't use any filler on these... one of the advantages of TIG is that with good fitup you can weld by just melting the parts together (called autogenous GTAW). I do have 347 stainless rods though for 321-321.

Dan W

ok, I'm going to get the stuff I need to run a purge line. I'll post the results when done.

I like the idea of laying the rod across a gap to fill it... I'm gonna give that a shot.

dade61782

I would recommend using a filler metal "dry washing" the parts together without filler metal can result in cracking. especially in high vibration situations The key is comfort and visibility work from the bottom up using a prop to steady your torch hand. have a tight fit and if you burn through turn your machine down stainless is more fluid than carbon and you can weld at much lower setting. laying the wire in the groove and washing over it is the way to start till you get the motion down. if you want flawless starts and stops leave your filler rod in your puddle and break the arc the rod will be welded to your work just rotate and start again. this will help to not leave big knots on your work

KBcobra

but if a filler is needed what material do you use.

jwscab

it depends on the material you are welding. for mild steel, er70s is good. if you are using 304 stainless, 308 is preferred in most cases. if you are welding 304 to mild steel 309 is preferred. If you are welding 321 stainless, then 347 is preferred. etc etc....

the main thing to remember is that you want to use a higher filler grade than what you are welding, to prevent the alloy from becoming diluted and weakened. the metallurgical aspects get very involved beyond this.

hobartwelders.com has a great forum.

Mathius

I don't think anyone else has mentioned this before, but you're new to TIG welding and its entirely possible that the black spots you see are because you accidently touched the tungsten to your work. This is a major PITA when welding aluminum, but when welding stainless, the weld pool will still flow, instead of turning to crap like aluminum. It usually results in unpleasant looking dark welds, sortof like I see in your pictures, but will rarely interfere with the actual shape of your bead.

You should never touch the tungsten to your work. It is not really supposed to be a consumable. Sometimes it happens by accident, particularly when you're a beginner. Tungsten causes major problems when welding aluminum. The tungsten burns hotter than aluminum, so when it flakes off, it contaminates your work to the point where 8/10 you can't keep your weld pool going. Whether aluminum or stainless, touching the tungsten to your work WILL contaminate the weld.

Regarding the problem you're having with purging the inside. They make rings that insert into each end of the pipe you're welding together. They sit inside the two pipe ends, and you can only see them on the outside like an 1/8". When you weld the whole thing together, the pipe inside acts as a sleeve, meaning you don't have to worry about purging the inside, and once you run your bead, you no longer see the 1/8" of pipe from the inside sleeve.

It might even give you better airflow as well. The inside of the sleeve is likely more aerodynamic than a weld bead inside your headers.

I forget what they call these rings, but I know Jegs carries them.

Mathius

ghettocruiser

iTrader: (4)

Ah yes... those little split rings for building headers... I saw them used on that Spike TV show Muscle Car before too. If I ever make a set of headers, which is highly unlikely, Ide definitely use those little things.

J.

heavy_chevy29

i dont want to get off topic, but what tig welder are you guys using. i would love to learn how to tig weld but i dont want to spend a $1000 or more on one. thanks alot

KBcobra

I dont know the really name but its the torch and filler metal method (old school lol). I've learned TIGing in highschool my self so I dont know the names just know how to weld aluminum and steel my self. Can't you MIG those pipes?

dade61782

You can tig weld with any ac/dc welding machine you just reverse the leads on the DC setting (just clamp the + on your table for the ground and hook a tig rig to the -side) and hook up some argon. you wont be able to weld aluminium very well as you will need high frequency to do that. You can get a cheap tig torch, flow meter, cups, collets, and tungsten on ebay just add argon and an ac/dc stick welder. st

84 trans am

Your weld looks pretty good for a beginner. Are you using a circular motionn or a figure 8 motion? I found it a lot easier to use the figure 8 because i could get a better looking weld but i know everyone has their own way. The discoloring is usually caused by touching the tungsten to the metal or the heat is turned up too high. Since you didnt burn through im going to guess it was the tungsten. As you practice more you will get it figured out but thats really a great start you have there.

Kory-88Iroc 350 tpi

iTrader: (1)

Maybe try turning up your flow meter from 20 to 35scfm. I weld 308 stainless every day. I notice that the puddle is less than optimal with the flowmeter set lower.
Just my .02
Kory

83 Crossfire TA

iTrader: (2)

does anyone make them in stainless? Hooker makes them in mild steel but I've never seen them in stainless.

Sonix

iTrader: (1)

I saw these once upon a time ago on summit. I can't find the link now, anyone?
I also can't quite picture how you'd use one. Basically a sleeve that goes inside one pipe, and you push the other pipe over it as well? But then you have a step down inside the pipe, i'd think that's much worse than a small weld bead. I can't be imagining their usage correctly here..?

Dan W

I added the 3" to 2 1/2" transition to this downpipe stub last weekend. I dont think i can create a better looking weld. For this one, I backfilled with argon and didnt use any filler.

I welded the one for the other side with filler but it doesnt look quite as good due to the extra filler material. Do you guys think i should space the parts apart a little to cut down on the filler material that makes an unsightly bump in the weld?

In any event, this is a test to see if the one w/o filler cracks under the same stresses as the one with filler.