ES Composite Pipe Repair

[Tom Buyrc]

I agree here, that over time the weight savings are not very much. The
carbon pipes absorb a lot of the oil, so I've found very little, if any,
weight savings. I've started going back to the aluminum pipes  --  last
longer and cost less.
 
-----Original Message-----
From: discussion-request at nsrca.org [mailto:discussion-request at nsrca.org]
On Behalf Of Rcmaster199 at aol.com
Sent: Tuesday, September 23, 2003 4:36 PM
To: discussion at nsrca.org
Subject: Re: ES Composite Pipe Repair
 
Maybe it's me but I just don't get this apparent love affair 
with the carbon pipes. Epoxy as the binder, as Gray states, is marginal
in almost all 4 stroke cases I have heard about. And to make these
things super light, you have got to make then thin, so strength is
doubly compromised, especially on four strokes with their 500+ degree
stack temp.

A hi temp plastic binder such as a PTFE emulsion, or maybe polyimide
emulsion is a better alternative but then the cost would be 2x and
impractical.  And ceramics, aka Space Shuttle heat shield tiles, are out
of this world (sorry Gray, I couldn't resist)

How much weight is actually saved over a "lightweight"ally pipe anyway?
The Greves is a little over 4 ounces, the Macs 20 cc is a little over 5
ounces and the Hatori is a little over 6. Are we talking, what, 4 ounces
tops?? Isn't there someplace else one could remove 2 to 4 ounces?

Hey, I am a big proponent of progress and composites offer great
advantages in the correct places, but I have to question if this is one
of these places

Firesuit..... hell forget the firesuit> I'm thick skinned enough,
literaly, so fire away

matt K



Subj:Re: ES Composite Pipe Repair 
Date:9/23/2003 6:38:01 PM Eastern Daylight Time
From:edbon85 at optonline.net
Reply-to:discussion at nsrca.org
To:discussion at nsrca.org
Sent from the Internet 



Gray, I'm listening. A short lived $200 plus pipe is not affordable
either. Short of going back to aluminum and the weight penalty, do we
have another alternative ??
Ed M.



----- Original Message ----- 
From: Gray E Fowler <mailto:gfowler at raytheon.com>  
To: discussion at nsrca.org 
Sent: Tuesday, September 23, 2003 5:40 PM
Subject: Re: ES Composite Pipe Repair



Concerning this repair, there is not a commercially available adhesive
that is going to do the job long term. The adhesive I used on Wayne's
pipe is an aerospace grade epoxy called Hysol 9394, rated at 350F. AT
350F this epoxy exhibits about 25% of its room temperature strength-and
this is about the best room temperature curing high temp epoxy
available-in short  all the stuff such as JB weld is crap at the
temperatures we are talking about. The inlet temp of our mufflers makes
for a brutal environment and unfortunately anything that cures at room
temperature just is not going to do the job very well. In reality Hysol
9394 is borderline. No easy answer here, and is evident by the constant
postings about burned out inlets....there is a problem with the
composite mufflers.  Actually there is an answer, but I do not think our
pattern market can afford it. 



 
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