REFLECTOR: Thermal exhaust Wrap

[Bob Jackson]

We considered ceramic coating the insides of our exhaust pipes, but got hung
up on how to handle the areas around the slips joints.  We put slips in our
exhaust design near each cylinder outlet to improve pipe life.  A normal
ceramic job coats the entire pipe and the reduced diameter of the inside of
the outer pipe prevents the inner pipe portion of the slip from fitting
inside.

It might be possible to tape off those parts of the slip joints so ceramic
is not depositing there.  Did anyone else that ceramic coated their pipes
have trouble with the slips?  How did you handle the ceramic coating around
the slips?

Another advantage of ceramic coating (or wraps) on a turbo engine (like
ours) is that it delivers more of the exhaust heat to the turbo, thereby
improving turbo energy extraction.  We ended up not ceramic coating, but
instead making loose-fitting circular shaped wraps with fiberfax type
insulation (like is used behind the firewall sheeting) sandwiched between
inner and outer layers of stainless foil (using rivets to hold the
'sandwich' together).  The wraps stand out from the exhaust pipes by about
an inch all the way around.  Our SS foil is about twice as thick as
household aluminum foil.  We have not yet flight tested our design yet.

Bob Jackson
Turbo Velocity XL
N2XF


-----Original Message-----
From: reflector-bounces at tvbf.org [mailto:reflector-bounces at tvbf.org] On
Behalf Of Alex Balic
Sent: Tuesday, October 09, 2007 11:41 AM
To: 'Velocity Aircraft Owners and Builders list'
Subject: Re: REFLECTOR: Thermal exhaust Wrap

I ceramic coated my exhaust before wrapping it- it still got blistering hot
even with the ceramic- I have used exhaust wrap on heavy equipment for over
15 years- these vehicles have semi-exposed engines and exhaust systems that
get wet every time it rains- I have not noticed any degradation in any
exhaust system as a result of the wrap. On my aircraft engine system, I over
wrapped the pipes with self sealing silicone tape in lieu of the silicone
spray that they sell for the same purpose- do not have very much run time on
the system yet, but it all seems to be holding up well

-----Original Message-----
From: reflector-bounces at tvbf.org [mailto:reflector-bounces at tvbf.org] On
Behalf Of Tom
Sent: Tuesday, October 09, 2007 8:22 AM
To: reflector at tvbf.org
Subject: REFLECTOR: Thermal exhaust Wrap

Ceramic coating is the long term way to go,( you can also coat the 
inside) The wrap will work but has two drawbacks:
1) It will greatly curtail the life of your exhaust system
2) you need to play with it every so often as it will start falling 
apart in spots