Exhaust tube materials

[lil_stewie7]

putting in a new exhaust tube in my SN while i have the tray out and re-foaming it. what have people used that worked and didn't work? is it worth making a carbon fiber one? stainless? aluminium? fiberglass? PVC?

TYIA
Stuart

 

[McDog]

No to carbon fiber. They tend to crack and/or leak.

 

[McDog]

Stainless or aluminum.

 

[lil_stewie7]

No to carbon fiber. They tend to crack and/or leak.

even for a scupper tube?

 

[McDog]

Pvc or abs ok for scupper tube.

 

[Christian_83]

No to carbon fiber. They tend to crack and/or leak.

Whats your reason for that statment?

 

[McDog]

Personal experience.

 

[Sanoman]

Hater....

 

[Jr.]

If the carbon tube is made correctly, with reinforcing thru the bulkhead to clamp area, and installed in hull correctly
You will not have an issue. Also use wide clamps on long tube attaching to distribute clamping pressure evenly.
Lastly, long tube needs to be supported mid tube, so when underway, it does not resonate to the bulkhead.

 

[Req]

Any thoughts on fiberglass instead of carbon @Jr. ?

 

[Jr.]

Any thoughts on fiberglass instead of carbon @Jr. ?

Glas is fine, just use epoxy resin. Heat is not a factor that far down stream.
Reason for epoxy is strength, with lesser fabric buildup.

 

[Req]

Glas is fine, just use epoxy resin. Heat is not a factor that far down stream.
Reason for epoxy is strength, with lesser fabric buildup.

I am assuming resonance is still an issue so attach it at the mid point as well? What thickness would you shoot for on the tube and the flange area?

 

[lil_stewie7]

Glas is fine, just use epoxy resin. Heat is not a factor that far down stream.
Reason for epoxy is strength, with lesser fabric buildup.

But there is anything in the mix (oil,fuel) that would break down the epoxy or material?

 

[Jr.]

I am assuming resonance is still an issue so attach it at the mid point as well? What thickness would you shoot for on the tube and the flange area?

To be honest, never built a tube from glass? But the carbon i have used 6 layers of 6oz twill, or 4 layers of 10oz twill
With an extra layer on the bulkhead end. As for midpoint, im refering to long rubber tube from waterbox.
That tube bouncing around is what can crack the tube thru the bulkhead.

But there is anything in the mix (oil,fuel) that would break down the epoxy or material?

Epoxy has very good chemical resistance. I know guys that have built fuel cells out of carbon with no issue!
So I would not be too overy worried on a part like an ex tube

 

[restosud]

i still would prefer stainless or even aluminum .
seen cases where cooling water was accidentally blocked off and pipes ran hot enough to damage the foam or the bulkhead.more so over on racing boats.
granted most other parts were damaged also but at least you won't have to also replace the hull tube!