Fluid level in a Sestrel hand-bearing compass

[Reptile Smile]

Hi all,

This is a video of a hand-bearing compass I got from Gumtree today. It was a tenner for this and a 12v spotlight, so I'm kind of ok whatever the outcome is...

The fluid level seems kind of low. There is what I presume is a drain/refill hole with a screw, rubber washer, and a label that says, "Fill only with water alcohol mixture .930 sp. gr." so I presume it can be re-filled - I just don't know whether it should be near as dammit full. Certainly at the moment, the needle bounces around a lot, and I think the inertia of fluid would help..?

 

[PeterWright]

Sestrel Radiant Hand Bearing Compass

Hi,

You're assumptions are quite right. I have had a Sestrel Radiant HB compass for over 30 years now. It should have no air bubble inside and filling to achieve this is not easy, but you can get there if you persevere.

You also need to ask yourself how your compass lost so much of its alcohol, and fix the leak. The most likely culprits are the filler plug you referred to and the cover joint held togethe by the set of screws around the top. In your video there is what looks like red Hermitite jointing compound around the cover joint, so maybe someone's had a go at resealing that at some time. I last overhauled my radiant in 1996, and it's still working perfectly - no bubbles.

Hope this helps.

 

[Oldhairy]

Long time no see, but I can only remember a tiny air bubble. It might even be meant to be filled right up. Is there anything that looks like expansion bellows?
The present level is in any case way too low.

Peter is faster. And better informed,

 

[Reptile Smile]

Brilliant - thanks for the advice.

There is a definite leak, and actually a smell of alcohol around the suspect area! I'd thought the gasket sealing was done with wax, though now I'm not sure. I think, then, I'll empty it, clean it, and then re-seal it with - what? Perhaps silicon sealant? Would that give the neatest finish?

Cheers

 

[jbees]

Did you manage to refill and seal your compass OK? There is another thread where someone claims success using silicon rubber and filling with baby oil.