Heat Shielding Experiment

atomsplitter

Living Legend
Joined
Nov 29, 2007
Messages
3,130
Location
Keller, TX
Ride
17 T-120 Black, 20 Bobber Blk, 22 Speed Triple RS
I wanted to see if it was possible to reduce the ferocious heat coming off the back cylinder header hitting my right thigh at stop lights so I decided on an experiment to see if it was possible. I purchased a 1 foot by 6 foot piece of Nomex cloth from Amazon and cut a small piece to wrap the back header pipe outlet above the heat shield. I tucked the excess cloth behind the heat shield and held this scrap on with a SS exhaust wrap tie. I wasn't concerned with the look, just heat dissipation. Took the bike for about 60 miles through urban roads with some highway thrown in to make sure it wouldn't blow off. It stayed put all the way and back to home. Roast levels on the right inner thigh were much much lower, so I'm going to double-up the thickness (plenty of room behind the heat shield) and see if I can get it down to being a nonfactor for foot placement at stops during idle. After I determine total effectiveness (and how many layers it takes) I'll look at high temp adhesives as a method of permanently affixing the material. If I can get the heat down to tolerable on the back pipe then I'll treat all three pipes.




 
Funny, been pondering having a seamstress do the same to my pants, maybe sandwich some thin woven glass or somesuch. If make it bilateral, might even look fine (if technical). “Rocket pants.” Small market, but may be on to something!
 
Nomex cloth is fire retardant, not necessarily heat proof.

The fibre starts to decompose somewhere around 370‑430 °C. Above that it chars and loses strength; it doesn’t give you magical insulation. The fabric will still conduct radiant or contact heat straight through to your skin, which is why racing and firefighting gear stacks multiple Nomex layers and air gaps to buy a few extra seconds, not minutes.

So the blunt truth: Nomex keeps a flash fire from turning you into a human torch, but it can’t stop you from getting cooked if you hang around the heat source. Treat it as a delay mechanism, not a heat shield.
 
Wouldn't standard exhaust wrap do the same or a better job? You could easily double (or more) layer it if necessary. To me wrapped exhausts look ugly as, but each to their own as they say.