[clive_su]

Hi, Clive here, I am attempting to make my own 4 into 1 exhaust system for my Kawasaki GPZ900R.
All parts 304L SS 1.5 inch x .063 inch wall thickness tubing and 0.125 inch wall thickness collars with .063 inch wall thickness sleeve for added support and good tight fit. Would like to Tig weld exhaust tube and sleeves to collar internally. have attached picture for clarity. Would appreciate your thoughts on the best way of doing this, torch size, tungsten, filler rod or autogenous weld etc. Thankyou

[Oscar]

Why bother using collars and sleeves and all that? forgive me, but I'm not a motorcycle guy. Is that the flange side that mates up to the head? Into a merge collector? Seems an awful lot of work to make something simple like an exhaust work.

[clive_su]

Hi, need a collar as each tube is clamped individually to cyl. Head and I am using slip joints into a merge collector using springs to hold each tube into collector, this is a common way of doing things on motorcycles, thanks.

[Oscar]

I see. You mention torch size. Do you have a variety of torches at your disposal? What do you currently have, and is that what you use for all of your tig welding? Any tungsten spec'd for DC will work.

[clive_su]

Hi, I have a CK17 air cooled torch but was thinking I should get a CK9 or CK24 torch with large Pyrex cup and gas lens to be able to extend the tungsten out, remember I am new at this so will practise on some dummy parts first.

[GreinTime]

The biggest struggle you'll have welding the inside face of the joint is fitting everything in there all at once. We do a lot of welds 3.5" down inside a 5" stainless tube at work (which is a far cry deeper than what you're doing) and the hardest thing as I mentioned is adding filler and not having the end of the rod do whatever it wants (which is normally stick itself to your tungsten.)

Personally, I would fuse the two pieces of 0.065" together, and then do a fillet weld between the collar and the tube end. A. You're now performing a fillet weld on ". 125" material instead of 0.125-.065-.065 B. If you go for a full height fillet, you can come back in with a die grinder and a sanding cartridge and smooth it all back out if you have any filler that crept up into the the tube.

A #9 torch with a stubby back cap and a #8 cup would do you fine, if you already have it. It's doable with any torch, it's just a matter of visibility after a certain point. Realistically, you can do the whole thing at 60-70a and use 0.045 308 filler and a 0.040 or 1/16 tungsten. The 040 is going to be your best friend because it's less intrusive.

Try a few joints with what you have already before you drop money on new stuff. You may find that you can do it comfortably with what you have.

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