I have been looking at getting some exhaust downpipes made of inconel but it is surprisingly hard to get this done. People are putting up all kinds of excuses including – yeah, you’ve guessed it – the war in Ukraine!
Following above report from @flyingfish I have contacted Goodfabs and will report on what I hear.
Goodfabs are eyewateringly expensive – 2.5k + 1.5k for jigs for a little pipe.
The US firms do these for about $500 but in stainless, not inconel. Inconel itself is pricey but in the context of an exhaust, irrelevant.
Do it yourself Peter as an owner supplied part or a repair with 1 gram of the old exhaust embedded!
You would probably do a much better job than the professionals and could always get a welder to weld the parts together 
High-temperature resistant ceramic covering of the exhaust system reduces heat radiation under the Cowling.
Ertl in Weiz, Stmk. offers high-quality products for exhaust coating. Different color tints are possible.
Are there any coatings that increase the strength and durability of exhausts?
Snoopy wrote:
Stmk
Stmk = Steiermark?
Yes… just copied the text from a experimental aircraft magazine and didn’t catch that.
I am wondering whether such a coating would make the exhaust tubing run hotter, due to reduced cooling due to airflow.
One would have to do a test flight with a sensor on the pipe, and measure the temp at various airspeeds.
Is it just on the outside (which surprised me), or do people do the insides too (what I’d always assumed)?
Jet Hot coatings and the like are all over the place here. They prevent external corrosion and preserve cosmetics. They also claim to reduce under hood temps on cars – which means the exhaust pipe is insulated and runs hotter, likely making internal corrosion worse.
Cars, motorcycles and the like do suffer from external exhaust corrosion in wet conditions but I’m not sure this would be as useful for aircraft.
Interesting if it prevents corrosion. Would this be allowed on a G-REG plane?
