Best Nozzle for Close Angle Merged Exhaust Tubing?

I made it this far merging a smaller (~2 inch) exhaust pipe into a larger 3 inch pipe (stainless steel), but I could not complete the weld because my #12 nozzle was too big! :P Is there a better nozzle size you experienced welders would recommend so I can finish the top of this merge section?

http://i876.photobucket.com/albums/a...s9216d4ce.jpeg
http://i876.photobucket.com/albums/a...ps4468dce3.jpg
http://i876.photobucket.com/albums/a...ps0140f6bf.jpg

And YES, I tried all different angles with the torch and protruding the tungsten out, it just won't fit :O.

Try a #6 gas lens or even a regular collet body, with as much stickout as required to get in there. You can use a foil dam on the other side to help hold the argon. In close areas like that, shielding usually isn't much of a problem. Just dam up the sides with foil and remember argon is heavier than air so it will fill up places like that. You might actually have to back down your flow to keep air from being sucked into the stream. Just pre-flow long enough to fill the area. You have to think about weld access when planing things like that. You can also probably reach that area from inside through your flange with a pencil type torch.

I agree with rambozo. tin foil is a staple of the professional welding shop. Not only does it work great as an air dam, but you can also fold layers of it together to make a heat shield, or as a spatter blocker if you're MiG welding over something important.

Aside from that, sometimes you can't get the puddle to go where you want on the tubing without burning holes in the thin wall tubing. On exhaust tubing sometimes its necessary to start building up the weld further up the tube, where you can get better control over the puddle and finally join the two sides of your seam together. On the outside it looks like you just have a longer notch joint than you actually do. This is a common practice when making exhaust systems, and having the extra thickness in those very acute angles certainly helps the longevity of the product. (these tight angles that face into the exhaust flow are the hottest parts odd the exhaust system)

The weld can be done, tho so don't give up! There's enough room to get a grinder in there and clean it out if you need to re weld.
The 6g restricted (6gr) test for ships and nuclear pipes makes you weld a stainless sch 160 pipe together boxed between 2 other pipes with a 1/2" clearance and you can't feet to the backside and have to TiG weld the backside of the joint with a mirror and your hands reaching around the bundle of pipes.

Not really relavent to your post directly, but check out this header from Sebastian Domingo of Next Level Racing / NLR Systems.
I have one of these on teh shelf for my bike. I bought everything to make my own and then jsut decided to buy one of his already done.

http://www.suzukihayabusa.org/forum/...topic=134596.0

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Originally Posted by sportbike

Not really relavent to your post directly, but check out this header from Sebastian Domingo of Next Level Racing / NLR Systems.
I have one of these on teh shelf for my bike. I bought everything to make my own and then jsut decided to buy one of his already done.

http://www.suzukihayabusa.org/forum/...topic=134596.0

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Nice work,,however I have to disagree with the method used to assure a flat surface on the header plate,,,welding here and there to straighten the plate is a hit and miss, trial and error method,,,much simpler to use a press and a straight edge,,,to get it close ,,,then a light pass on a milling machine to assure a flat surface...other than that the header work is very good,,,nice looking product

As far as welding in a tight area with the tig,,,if the cup won't get you there,,you may want to finish the weld with O/A,,,

I agree with Rambozo, a gas lens and a huge stickout will probably work. The aluminum foil trick I've never heard of but sounds interesting. Would probably work just fine too.

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Originally Posted by Spike

The weld can be done, tho so don't give up! There's enough room to get a grinder in there and clean it out if you need to re weld.
The 6g restricted (6gr) test for ships and nuclear pipes makes you weld a stainless sch 160 pipe together boxed between 2 other pipes with a 1/2" clearance and you can't feet to the backside and have to TiG weld the backside of the joint with a mirror and your hands reaching around the bundle of pipes.

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That just sounds like a pain in the ###.

When I have to get into very small places I us standard collects and holders with long cups preheat if possible and set gas flow differently for the small ends just test it on a part to see how it work before doing the big job. Use type B solar flux in side the pipe if stainless steel then you don't have to use argon in the pipe. The flux provents burn throught, ozide inclusions and aids controlled penetration also elimiates porosity. GOOD LUCK
Attachment 9135

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Originally Posted by Kempy

When I have to get into very small places I us standard collects and holders with long cups preheat if possible and set gas flow differently for the small ends just test it on a part to see how it work before doing the big job. Use type B solar flux in side the pipe if stainless steel then you don't have to use argon in the pipe. The flux provents burn throught, ozide inclusions and aids controlled penetration also elimiates porosity. GOOD LUCK
Attachment 9135

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lol... nozzle envy.

Quote:

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Originally Posted by Kempy

When I have to get into very small places I us standard collects and holders with long cups preheat if possible and set gas flow differently for the small ends just test it on a part to see how it work before doing the big job. Use type B solar flux in side the pipe if stainless steel then you don't have to use argon in the pipe. The flux provents burn throught, ozide inclusions and aids controlled penetration also elimiates porosity. GOOD LUCK
Attachment 9135

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Do those require you turn the flow down a lot?

Quote:

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Originally Posted by geezer

Nice work,,however I have to disagree with the method used to assure a flat surface on the header plate,,,welding here and there to straighten the plate is a hit and miss, trial and error method,,,much simpler to use a press and a straight edge,,,to get it close ,,,then a light pass on a milling machine to assure a flat surface...other than that the header work is very good,,,nice looking product

As far as welding in a tight area with the tig,,,if the cup won't get you there,,you may want to finish the weld with O/A,,,

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In this case it is not hit and miss. He makes quite a few of these and pretty much has it down pat. I agree for a one off, but he has the procedure pretty well figured out. THese were from a while ago. He now uses a CNC flange, mostly for appearance. He is currently working on a new version starting with electro polished weld Ells. Should look pretty good.

I turn it down a little even when using smaller standard cups but if I get into tough spots I turn it up a little. You have to play around each cup and regulators are a little different and beening water cooled or gas cooled. The longer ones I some times turn it up if I am using a lot of power for the size of cup to help cool it. I use a long post flow to help cool the cup after welding.

This guy gets good results on narrow angle stainless merge collector with what looks like something in the area of a #6-#7 gas lens, and maybe a cup width's worth of stickout; I'd say. (see his stickout @ 1:50)
http://www.youtube.com/watch?feature...c3AQFHI#t=105s

Running a cup width's worth of stickout is not hard to do with a gas lens. You can run even more stickout than that if necessary, with the right conditions and setup. Note, if you can set up your workpiece so the tungsten is pointing straight down (1G position), the heavy argon will tend to fall down onto the hot weld metal.) You should of course try and do this work indoors in a still (non-windy) environment.

If you use a larger diameter cup, you'll probably need to stick your tungsten out further, and use more gas to have it work. A #12 cup may need 30 or so cfh to work best, where a #8 needs 15 or more cfh. A #6 can use 12 cfh or so. The area of the cup increases with the square of the diameter (cup size), and IME, the gas flow should increase proportionally to the area of the cup for best results. The wider cup will shield a wider area of hot metal than the narrower cup. Be sure to run enough pre and post flow. Proper torch angle is also very important. (Don't angle it so that you draft air in next to the hot metal)

Using a sufficiently small diameter tungsten (I'd recommend 1/16" for what you're doing, not 3/32") and having a pointed, clean, contamination free tip may also be necessary to keep the arc coming off the very end of the tungsten (not off to the side).

Also - make sure your filler rod is sufficiently small diameter to reach where it needs to go, because if it can't reach the puddle, then the puddles are going to need to grow in size until they can get bridged across by the filler rod. You may need to change your "angle of approach" with the filler rod to get it deep into the groove, where it's needed.