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How to TIG this flex coupler to exhaust pipe?

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How to TIG this flex coupler to exhaust pipe?

Postby Mojo88 » Sun Oct 08, 2017 2:36 pm

I have some stainless steel flex couplers, which I want to weld into my exhaust system (also stainless steel). The exhaust pipes are .060" wall thickness, while the metal on the flex couplers is much thinner. It looks to me that as soon as I start trying to TIG these together, I will just blow away the metal on the coupler.

I have included some pics below, with some numbers (like a little numbering system, for reference sake), so maybe someone can tell me where to focus the heat? Should I be mainly heating on #4 (the pipe) with the goal of attaching to #3 only? Or should I be trying to get all four numbers fused together? It seems like a daunting task and I am a relative noob at TIG.

Any help would be appreciated. Thanks very much!

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Re: How to TIG this flex coupler to exhaust pipe?

Postby Oscar » Sun Oct 08, 2017 3:29 pm

Image

:lol:

No practice part available + relative TIG newb + unsuitable actual part + crappy fit-up/gaps = disaster waiting to happen.

Sorry, but while it can be done, I would avoid the headache if I were you. All of those little wires will melt away regardless of where you focus the heat if you don't move them out of the way.

But naturally I've been there too, so here goes. Pull the wire braid back at least 1" (meaning you should also pull up/off that slip ring over it). You will have to get creative for this so it doesn't unravel. Build up the outer circumference of the plain exhaust tube ~1/16" to take up the slack from that grand canyon sized gap (Good luck with this if you don't have a pulser). Then weld the inner flex tube to the exhaust tube as a lap joint. Once that is taken care of, then let the wire braid slip over back in place, along with the slip ring. I can't "feel" the tolerances so hopefully they allow for it.

or just get it in this style:

http://www.ebay.com/itm/Vibrant-Perform ... bb&vxp=mtr

http://www.ebay.com/itm/2-Exhaust-Flex- ... Yr&vxp=mtr

learn from your mistakes and call it a day. :D
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Re: How to TIG this flex coupler to exhaust pipe?

Postby Mojo88 » Sun Oct 08, 2017 3:37 pm

Oscar wrote:....No practice part available + relative TIG newb + unsuitable actual part + crappy fit-up/gaps = disaster waiting to happen.

Sorry, but while it can be done, I would avoid the headache if I were you. All of those little wires will melt away regardless of where you focus the heat if you don't move them out of the way......


Hahahaha, yeah man, I was thinking all the same thoughts, which is why I posted this thread. I will probably end up buying couplers with pipe stubs already attached.

Thanks!
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Re: How to TIG this flex coupler to exhaust pipe?

Postby Poland308 » Sun Oct 08, 2017 3:52 pm

You might be able to expand the tube and slip it over the ring on the coupler. That would make it a lap joint that would be easier to weld.
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Re: How to TIG this flex coupler to exhaust pipe?

Postby Jakedaawg » Sun Oct 08, 2017 5:51 pm

It looks like the ring on the flex is to slip inside of an existing pipe. I have never used the stuff so take the comment as being worth nothing.
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Re: How to TIG this flex coupler to exhaust pipe?

Postby Louie1961 » Sun Oct 08, 2017 6:41 pm

Silicon bronze maybe??
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Re: How to TIG this flex coupler to exhaust pipe?

Postby MarkL » Sun Oct 08, 2017 7:07 pm

You don't need the braided cover for your application, so you could take it off. I'm not sure that helps in this case because the fit is still poor. The braid is only needed to allow the bellows to meet a pressure rating, but you're not applying any pressure.
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Re: How to TIG this flex coupler to exhaust pipe?

Postby cj737 » Sun Oct 08, 2017 7:12 pm

One thing I've had success with when welding SS thick-to-thin is a fusion weld, but WITH a back purge. I appreciate the woven SS coupler will bleed argon, but you could tape it/cover it with aluminum foil to help. This would allow you to fuse #3 to #4, then #2 to #3, then #1 to #4. It may make controlling the heat required for 1/16" filler easier to manage. A large cup, a generous pre-flow, and a generous post flow will help.

Whatever amps you set, make sure its hot enough to puddle instantly so you don't cook the SS.
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Re: How to TIG this flex coupler to exhaust pipe?

Postby Poland308 » Sun Oct 08, 2017 7:19 pm

It looks like it has a liner that keeps it from leaking.
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Re: How to TIG this flex coupler to exhaust pipe?

Postby cj737 » Sun Oct 08, 2017 7:39 pm

Poland308 wrote:It looks like it has a liner that keeps it from leaking.

You mean for the back purge? Might be right. Didn't/couldn't see it clearly.
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