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CeraKote on Vetterman exhaust

von_flyer

Well Known Member
Advertiser
Has anyone coated their exhaust with CeraKote?

I am looking at the V series CeraKote rated to 1800F. I have questions for anyone who has experience with CeraKote.


"Cerakote V Series ceramic coatings are the unrivaled leader in high temperature thin film performance coatings, capable of temperatures up to 1800°F. "
 
You might try a SEARCH on VAF, perhaps using Google search engine, for exhaust coating. There has been much discussion of the topic in the past here on VAF.
 
I had my exhaust ceramic coated by a local company, don't know the brand but they claim 2000 degree coating. Here's why I did it, reduce engine compartment heat, resist chipping and rust. The pipes are coated inside as well, and literally can touch the pipes minutes after shutdown.
 

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I had my Vetterman exhaust Cerakoted by a local shop. I looked at JetHot and they were almost 3X the cost and I would have to ship. Not sure I can claim better power or less in cowl heat vs not coated but it looks nicer.
 
Heat muff?

I had my exhaust ceramic coated by a local company, don't know the brand but they claim 2000 degree coating. Here's why I did it, reduce engine compartment heat, resist chipping and rust. The pipes are coated inside as well, and literally can touch the pipes minutes after shutdown.

Did they mask off the area where the heat muff sits? Is this an internal and external process? Thanks!
 
moving parts

How do they handle the parts of the exhaust that move, like the slip joints, ball joints? When I had a subaru I had jethot coat the exhaust inside and out, but it was a single-piece system. Not sure how these lycoming pipes will deal with the thermal difference between coated and uncoated parts. Would be great to check in with you guys that have done this after a few years.
 
What is the purpose of the coating?

different benefits, however, the concept started in the hot rod world. By insulating the pipe (asbestos wrap or ceramic coating), you keep more heat in the exhaust gas itself (insulation prevents heat transfer from gas to metal pipe). The hotter the gas in pipe, the greater velocity it maintains. That velocity increases the gas movement across the entire stream (closed system) from the exh valve and therefore pulls more fuel air mixture into the cylinder during the overlap period between int/exh valve opening/closing. In this regard, the benefit is similar to reducing back pressure in the exhaust. A highly designed header system will do something similar by leveraging pulse intersections to create suction.

Larry
 
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Vetterman's site

just an fyi...from the Vetterman site:

Can I wrap my exhaust with automotive type of wrap material and obtain more power?
Any material on the exhaust will shorten it's life and failure will occur. We are using air cooled engines and one the best heat sinks on the engine is the exhaust system. The mass air flow comes in and is forced down and around the cooling fins and then is directed over the exhaust system and then exited out the bottom. If the exhaust is covered it cannot aid in the cooling process. Our tests show that any type of wrap on the exhaust makes both the cylinder head and exhaust temperature run higher. The stainless steel used (type 321) will degrade if the surface temperature is over 1250 degrees F. We also did not find a power increase of any kind by wrapping the exhaust.

How about ceramic coatings?
The jury is still out on them as to whether there is any benefit, however as stated above, they have the same effect as wrapping the exhaust. We do know that once a ceramic coating is applied, the system can never be repaired as it gets into the pores and welding is not possible. How about cooler cowl temperatures with either of the above? Yes, the temperature in the cowl will probably be cooler, but the engine produces so many BTU's of heat so it either is kept cool by the mass air flow or it stays in the cylinder heads.
 
But it over heats the pipe! Aircraft pipes are made from much thinner stainless than automotive pipes and therefore cannot withstand the heat as well. Ceramic wrap nearly destroyed my first pipe! Ceramic coating may be kinder but I would keep a close eye on what happens over the first 50 hours.
Pete
 
I'm going to assume that the idea of adding ceramic is to decrease the radiation heat transfer from the pipes to the surrounding cowl area. I'm not sure what else a thin layer of ceramic could do. A very thin layer of it certainly isn't a good insulator.

Thermal emissivity is the property of a body to either radiate away or receive thermal radiation. A "black body" has coefficient =1. A coefficient of 1 means it can accept (or radiate away) the maximum amount of heat. So, if we want to minimized the radiative heat transfer from our pipes to the surrounding under-cowl objects, we'd like a low coefficient.

The coefficient of thermal emissivity for oxidized stainless steel is about .9, about the same as for ceramics, at least those I could find. However, polished ss has a very low coefficient of about .08, depending obviously on the degree of polish. Seems to me if the goal is reduced under-cowl temperatures, polishing the pipes might be the way to go.
 
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