question regarding header & tuned pipe

[Koenig, Tom]

Gray,
 
I believe Ed once told me he sourced his resin from Morton Thiokol, but he
didn't elaborate what it actually was. I guess I can understand that. Maybe
they get it from Shell ??Unfortunately the pipe I had from him ended up a
molten blob. I should never have put it behind a screaming 140L. Now, I cant
even use it as a mantle piece ( along with my OS 120 SP <VBG>)!!!
 
At least he offered that much info, which I respect him for.
 
 Bolly flat out wouldn't tell me the resin, nor would he sell me some so
that I could attempt to repair the ES. My experience sofar is that I would
be hard pressed to try another carbon pipe behind a 4 stroke. The DZ does
seem to run considerably cooler, so it may be worth another experiment when
I have some time to burn...which probably wont be for another 20 years or so
<VBG>
 
In comes Mr Hattori San, which is a little heavier. But it doesn't leak or
melt, and in my opinion sound much softer.
 
 
I was told that the high temp epoxies have an extremely short shelf life (
apart from being very expensive)  Is this so?

[Koenig, Tom] 
 
 
 -----Original Message-----
From: Gray E Fowler [mailto:gfowler at raytheon.com]
Sent: Wednesday, 26 March 2003 6:25 AM
To: discussion at nsrca.org
Subject: Re: question regarding header & tuned pipe




Without actually being privy to what these guys are using resin wise, but
experienced in identifying cured resins, I would venture to say the the ES
pipe is an aromatic amine cured epoxy that is made by Shell Chemical , 8500
series. It is a liquid that cures at a temperature about 200-250 F then can
be post cured to give a glass transition temperature (Tg) of about 350F.
This means at 350F the resin goes from the hard glassy state to a more
"rubbery" state. The Tg is usually when there is little to no structural
capability, but these temperatures do not necessarily damage the resin. When
over exposed to temperature above the Tg like the 425-450F exhaust, the
resin will break down.   The Bolly appears to be a Bismaleimide resin which
is a room temp semisolid resin that has a Tg of 425-450 hence better header
exhaust resistance.  The leaking of the pipe is most likely a result of the
wet-layup manufacturing method us! ed, leaving pinholes. Bolly's also have a
kevlar outer layer which absorbs water which gases off during cure creating
pinholes. 
And then there is the chance I am guessing wrong...... 





Gray Fowler
Principal Chemical Engineer
Composites Engineering 



	s.vannostrand at kodak.com 
Sent by: discussion-request at nsrca.org 


03/25/2003 12:47 PM 
Please respond to discussion 


        
        To:        discussion at nsrca.org 
        cc:         
        Subject:        Re: question regarding header & tuned pipe




Bolly mufflers use a very different kind of resin that is more temp
resistent than the ES pipes.  It will become brittle over time, but will not
ablate.  Bolly's also eventually leak like a seive over their length
eventually. 

--Lance 



	Ron Lockhart <ronlock at comcast.net> 
Sent by: discussion-request at nsrca.org 


03/25/2003 10:11 AM 
Please respond to discussion 

        
       To:        discussion at nsrca.org 
       cc:         
       Subject:        Re: question regarding header & tuned pipe




Lance,

Would you know, is the end of the pipe being exposed to exhaust 
gas a concern with the Bolly pipes & mufflers?

TIA   Ron Lockhart

----- Original Message -----
From: s.vannostrand at kodak.com
Date: Tuesday, March 25, 2003 10:52 am
Subject: Re: question regarding header & tuned pipe

> Every change in backpressure, due to the expansion chamber or 
> header change will cause a wave reflection, however, the effects of 
> necking down from 7/8 to the approx 3/4" OS pipe will not be much.  
The bigger problem is that if the pipe is composite (CF) you will 
ablate the pipe input and ruin the pipe.  I've seen 3 of these for 
repair.  The hot exhaust gasses can not be allowed to contact the end 
of the fibers and resin for most resins.  ES pipes fail in this 
fashion.  Some people have been successful in using a squishy coupler 
(like the Macs grey) but this is not a reliable setup for most people. 
> 
> The Mintor carbon fiber pipe (I have a N.I B. one for sale for 
> $160 including shipping) uses an aluminum inlet to prevent this.  I 
> also have a Macs to OS adapter made from aluminum for $12.
> 
> -Lance


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