Anybody topped off a compass before? Best to order some "compass fluid"? Any tips would be appreciated. Probably only need less than an ounce, can just see the top of the liquid when in steep climbs.

my experience with compasses has been when they start to leak, fix the leak first rather than fill the compass several times then fix the leak, it's always been the diaphragm on any leak I've had. aircraft spruce has the parts, but shipping will cost more than the parts.

http://www.aircraftspruce.com/catalog/i ... airkit.php

as for actually filling the compass, do it OUTSIDE because you will spill some fluid and it's hell to clean up. my best luck has been to put the compass in a disposable bowl or clean margarine container, fill it slightly overfull, then but the plug in the top, which will spill more fluid but should get it full with no bubbles. I'm sure other people will have other ideas about filling a compass.

Dale Moul wrote:...it's always been the diaphragm on any leak I've had...put the compass in a disposable bowl or clean margarine container, fill it slightly overfull, then but the plug in the top, which will spill more fluid but should get it full with no bubbles...

+1

Replacing the glass and cork front gasket in my experience is an easy way to crack the new glass, then need to replace it with the old glass all the while being extra careful not to over tighten the screws but leading to another crack across the face of the compass within minutes...

what brand of whiskey do you use?

An old timer once mentioned to me that clear Johnson's light baby oil works well. Less prone to leaks, lubricates the parts, won't dry out the seals, and damps the compass movement just a little tiny bit to make is easier to read.

The very next time I need compass fluid I'm going to try this, makes sense to me. If anyone here knows different, or can think of something that would make this suggestion inappropriate, speak now !

At one time in history compass's were filled with alcohol, diaphragms were made of latex, leaks were common, and topping off a compass with whiskey or any other booze available was common. diaphragms are now synthetic and can last up to 20 years in a hangered aircraft, and compass fluid is very pure, acid free, kerosene (8 oz. for $1.70 at aircraft spruce). If you start pouring strange organic compounds into your compass you may find one that will turn your diaphragm into a glob of black goo which will gum up the internal parts and you will need to buy a new compass ($135.00 at aircraft spruce). Just my $.02 worth.

That's very disappointing to hear. I always imagined I'd have a good ounce and a half worth of warmth while I wait for the angel of death.

Baby oil could work well when it's warm but what about if it gets too cold?
Experimental A/C only of course.

I got tired of maintaining my OEM Airpath in my P172D. It was requiring a swinging every few months, it was leaking, and finally I said screw it, I want a new one. There was a thread right here on BCP about compasses, which led me to getting a new SIRS compass from Spruce. Looks a little funny, but once swung, it hasn't wavered a bit--still accurate after a year. It's much easier to read, too, both day and night.



Cary