912 exhaust connections

[Jerrytex]

Is is necessary to use the copper antiseize compound on the 4 slip joints on the 912 exhaust where the exhaust pipes slip into the muffler. I know I used it on the 582 exhaust but not sure if I need to do it on the 912 exhaust.

[Dorsal]

I believe the instructions specifically call for it.

[DesertFox6]

...AND...the day will come when you will be very glad you DID use it, Jerrytex; it's only a matter of time. It's cheap insurance against "Fox Bites" on your hands when you need to do anything with the exhaust system. I also have four Harleys to take care of, and the same is true in protecting against "Hawg Bites" from those critters too: Not to mention allowing your very expensive exhaust parts to "float" as vibration dictates without seizing and cracking as a friction-welded unit.

I'll back, and expand on, what Dorsal and DesertFox4 said: Always use anti-seize on your spark plugs and exhaust hook-ups; if it's good enough for mandatory military use in such cases, it's good enough for me!

"E.T."
(With scars to prove it! )

[Jerrytex]

Copper anti seize it is. Just on slip joints or on the down pipes where they go in to the heads too? Seems like it wouldn't cause any issues.

[Dave S]

Got a related question - I know of several mechanics who use aluminum/paste based anti-seize compound - particularly for spark plugs - but also on exhaust components.

What kind of luck have people had with this stuff in place of the copper anti seize compound?????

Sincerely,

Dave S

[DesertFox6]

I've always (30+ years) used the aluminum based product from Loctite Corp.; it's called Permatex Anti-Seize Compound. It's formulated particularly for aluminum block engines and related components. It's fantastic on cylinder lug bolts, spark plugs and exhaust slip-joints; anywhere it going to be HOT with the attendant expansion/contraction problems when the parts cool.

You can find it at almost any auto-parts store; a one ounce tube cost a few bucks and I think the one hanging over my work bench is at least 10 years old and still saving knuckles. It was just as fresh and spreadable as new when I put my 912's exhaust system back together last year following an overhaul, and felt just as new on some Hawg plugs I changed out last month. Like I said, cheap insurance!

"E.T."

[Jerrytex]

I have developed 2 cracks on the muffler in less than 100 hours! Not very happy right now. I used the copper anti-seize and I can't seem to get this (expletive) muffler off! Any tricks?

[jrevens]

Hi Jerry,

There are all kinds of things you can try. Gentle tapping with a plastic mallet, then application of heat around the perimeter of the outer tube... don't leave the heat (e.g.- propane torch) on too long. The idea is to expand the outer tube without too much heat soaking through to the inner tube. I've also had some success with Mouse Milk. You can get that from Aircraft Spruce. Let it soak in for awhile. Another thing to try- heating, then plunging into ice water will sometimes break it free.

When you reassemble, I've found that the very best anti-seize is the nickle-based stuff. It's silver colored like the aluminum-based, but has a much higher temperature rating - even higher than the copper stuff (I think around 2200 deg?) It's also very compatible with & recommended for stainless steel.

[Dave S]

John,

Haven't heard of the nickle based stuff till you mentioned it today....where does a person get it?

Dave S

[Jerrytex]

Well I got the exhaust off. Was not pretty. I freed one joint freed up but the other three stayed seized up until I bent everything up to get it off. Had to use an acetylene torch to get the three seized up joints apart. Needless to say, this is probably why the muffler cracked. A friend that has forgotten more about planes than I'll ever know is helping me now. He welded the cracks and we are sanding the joints to give them room to expand. Going back with a nickel base anti-seize. Thanks for the replies.