Exhaust Pipe Corrosion

[gnflyn]

Just a question for the group.
The end of the exhaust system that is exposed beyond the cowl on my BC-12 seems to just melt away. I have replaced the exposed section three times in 10 years so far, the most recent being today. The section of piping above the carb heat muff exit stays just fine, only the exposed part.
Is this a common issue? It usually starts as pinholes around the exit point below the heat muff and then keeps going. I have tried all sorts of paints on the exposed part to no avail......
Any guesses???

[urban]

Re: Exhaust Pipe Corrosion

Someone suggested stuffing an oily rag into the tail pipe if it's going to sit for awhile....at least I hope it was the exhuast he was referring to

[jdoran]

Re: Exhaust Pipe Corrosion

Could the end of the pipe be touching up against a dissimalar metal such as an aluminum cowling?

[mohawktipi]

Re: Exhaust Pipe Corrosion

If you park in a hangar, try hooking up a ground wire. Doesn't eliminate corrosion but really slows it down.

[gnflyn]

Re: Exhaust Pipe Corrosion

It is hangered here in Florida. The only other metal it may touch is the aluminum heat muff. It does sort of look like galvanic corrosion. I will hook up a ground wire and see if that helps. A good idea...

[Forrest Barber]

Re: Exhaust Pipe Corrosion

How are you fixing it each time? Rumor has it that some people cut off pipe and slip an extension over it ; chromed too! NAPA Aviation stores have them

[jim cooper]

Re: Exhaust Pipe Corrosion

5.95 at Napa. Looks Good! Screwed on and saftey wired. Half hour project. JP

[N74DV]

Re: Exhaust Pipe Corrosion

we had the section that exits the cowl replaced with stainless pipe a few years ago. Then at the last annual in June we took off the entire exhuast pipe (required removing the engine) and sent it out for interior/exterior ceramic coating. It cost $200 to have it coated but it should now last longer than I'll be walking this planet.

[fearofpavement]

Re: Exhaust Pipe Corrosion

heat muffs should be made of stainless or inconel, not aluminum.

[Hank Jarrett]

Re: Exhaust Pipe Corrosion

They should actually fit too, unfortunately they are aluminum and they DON'T fit well. An STC for a redesigned exhaust system that can be removed without taking the whole nose apart should be a VERY high priority. My mechanic and I have been looking at it but haven't found a simple solution so far. My main worry is splitting the exhaust in the cabin heat side raises the risk of CO in the cockpit. I wouldn't mind a joint in the Carb heat side, but that doesn't help much to remove the exhaust on a mounted engine.
Hank

[Marv]

Re: Exhaust Pipe Corrosion

I thought i read on the forum a while back that someone had started making a stainless exhaust system for taylorcraft in two peices, so you did not have to remove the engine to take the exhaust off. If this is right ,why are we trying to find something else? With stainless you should never have to remove the exhaust unless you were doing some engine work. Marv

[Robert Lees]

Re: Exhaust Pipe Corrosion

Many moons ago, being fed up with having to remove the whole mild-steel exhaust for repaires almost every year, we put a flanged joint in. The joint occasionally leaked, but not severely.

About 8 years ago, we had a new custom-built stainless one made, again with the flanged joint.

When I modified the exhaust to fit the C85, we had the joint welded closed, since we had never had to take it off. 18 months later, it's still on, and we have never had any cracks or deterioration (and no leaks at the joint!)