Plumbing for stacks - flex or rigid?

[Ceejmo]

I'm in the process of adding a single stack to my truck. The horse's heads stick out of the left side of the trailer and the black smoke will go down the right side.
I have fabricated and installed all of the mounting brackets, base and fittings along with the purchased stack. All that is left to do is to cut the existing pipe and attach it to the connector that I made for the stack. Should the piping be solid pipes or flex pipe? I have been trying to find a section of 3" flex pipe but am having no luck. I can order it from NAPA or O'Rielly. The Azone just gave me that deer in the headlights look. From these places I have to buy 10 or 25 feet. I only need about 18 inches.
It seems to me that if I connect it using solid pipe that the tourque of the engine and the slight twisting of the frame and body on rough roads (live down a dirt road) will eventually work the connections loose. Any thoughts on this? Or any idea where to get a short piece of 3" flex?

 

[93turbo_animal]

I have used flex on all 3 that I have done and have had no problems I have no idea other wise but I would go flex pipe better safe then sorry

 

[MIDNIGHT RIDER]

I got a pre-cut 3' joint of 3" flex at NAPA, galvanized for something like $10; if I had wanted to go to the next town over, their NAPA had it in stainless for about $20.

3" flex is not that un-common and stores around here that have it in rolls will sell it by the foot and cut off what you want.

Definitely go with the flex; if nothing else, it will cut back on solid connection reverberrations.

I had two seperate trucks that had solid connections to the stacks with no major gripes; but, flex is better.

 

[F350camper]

this is a really good place to deal with if you end up having to order. http://store.airflo.com/ss3.html

 

[Ceejmo]

Perfect F350Camper! Thanks for the link. And thanks to all for the input.

 

[sle2115]

I used all ridgid and installed a 3 inch flex coupler. I bought it on ebay, but Summit Racing sells them as well, just another idea. I have seen flexpipe leak and didn't want to go that route, but there are many different kinds, some much better (and more expensive) than others. Here is what I used - http://store.summitracing.com/partdetail.asp?autofilter=1&part=PSM-82-4218&N=115&autoview=sku

 

[Classicfordguy]

I am working on fabbing an exhaust for my 94 f250 turbodiesel, I have been trying to make a 3.5 in rigid downpipe, would this flexpipe work for the downpipe portion of my exhaust instead of a rigid pipe?

Thanks,

-Rob

 

[MIDNIGHT RIDER]

The down-pipe is at the hottest point of the exhaust, once it leaves the turbo.

The flex will work if you can make it hold its shape once installed; also, you would have to have a portion of rigid at the turbo flange, as the flex doesn't make a good connection at this point.

 

[Classicfordguy]

Yup I was planning on welding a homemade flange to the outlet housing thenusing some sort of exhaust clamp. Which would hold up to heat he best, galvanized or stainless? The rest of my piping will be galvanized.

Thanks,

-Rob

 

[Joe Mc]

Stainless will handle the heat better. Watch heating galvanized, the fumes are poisonous.