Sestrel compass

[Captain Altemus]

Hello all, just acquired a antique Seattle compass binacle , has a crack in the glass. Trying to figure out what type of glass and type of fluid. The number on the binacle says 88992R any idea how to find info on this
Sincerely
Capt John A.

 

[VicS]

A photo might aid identification

Sirs Navigation may be able to help SIRS - Compass Applications - Marine but they appear to be suggesting BPSC Marine for repairs to older compasses BPSC Marine - the one-stop instrument repair of your compass or compasses

 

[Halo]

Welcome to the forum.
If you use the search facility you will find lots of old threads debating compass fluid. I would try and smell what you have in there and see if it gives you a clue. Personally I have used gin and white spirit with good results (not in the same compass) but don’t take that as a recommendation for yours.
If you are replacing the glass I can’t see why you wouldn’t use normal float glass with the same thickness

 

[wazza]

BPSC Marine helped me if I remember correctly with my Sestrel. I had a problem with the diaphragm and the sealing ring.
Lamp oil is good enough to fill it. I have bought dedicated compass oil (more expensive of course) but as I had a leek it became expensive. But now with all sealed I’ve used lamp oil/paraffin. Works a treat.

 

[Captain Altemus]

Thank you all for the information very much appreciated. I also read online That the fluid could be radioactive due to the paint, I don’t always believe everything I read online but it does raise an eyebrow. I tried to add a photo but it said the server cannot handle it. And What is float glass?

 

[penberth3]

Thank you all for the information very much appreciated. I also read online That the fluid could be radioactive due to the paint, I don’t always believe everything I read online but it does raise an eyebrow. I tried to add a photo but it said the server cannot handle it. And What is float glass?

Radium paint hasn't been used for decades, not sure how old your compass is. If it is Radium you've got a problem! Tritium is the more recent thing, also radioactive but not as bad.

 

[ltcom]

If the radium (probably) has flaked off the card and is floating around in the fluid, the flakes will be radioactive, but it does not dissolve in the fluid, so the fluid is ok. This I was told by this forum. Radium is a mustard / orange / brown colour.....see youtube.
If you cannot get an answer from compass repairers, but you can syringe some fluid out (without flakes of radium), take a small sample and put in small test tubes (ebay). Add alcohol (vodka) to one tube, water to 2nd tube, white spirit to 3rd and bay oil to 4th. Don't need to do all tests, just progress until you find an answer. Start with adding distilled water, then alcohol imo. Whichever mixes with the original fluid best (hopefully distilled water works), use that. My old WWII compass was alcohol and water. My newer compass was oil and I added baby oil /white spirit mix. Both work fine still. Remember to find leak and repair that too..... hopefully just a worn gasket on a filling screw.
The radioactive particles will not harm you as long as you do not touch them, ingest them or inhale them. If left in the compass, the radiation should not reach you. So I was told. Lots of info on youtube repairing compass.

Any of these?
google images

 

[penberth3]

..........The radioactive particles will not harm you as long as you do not touch them, ingest them or inhale them. If left in the compass, the radiation should not reach you. So I was told. Lots of info on youtube repairing compass.

I think that's wrong. The radiation will be detected outside the compass - so it is reaching you.

 

[ltcom]

I think that's wrong. The radiation will be detected outside the compass - so it is reaching you.

I was told the radiation would be absorbed by the fluid, glass and very little would reach me unless I slept with it under my pillow. Perhaps a scientist will be along soon to confirm or deny.

 

[VicS]

I think that's wrong. The radiation will be detected outside the compass - so it is reaching you.

I was told the radiation would be absorbed by the fluid, glass and very little would reach me unless I slept with it under my pillow. Perhaps a scientist will be along soon to confirm or deny.

The radium isotope used is an alpha particle emitter.

Alpha particles are dangerous if the isotope is ingested or absorbed because they are relatively large and can do a lot of local damage. However they are easily screened. A typical demo experiment is to show how they can be stopped by a sheet of paper.

Tritium , used in "beta light" illumination is a beta particle emitter. Beta particles are very much smaller and although not so easily stopped do very little damage. They just whizz through you

Tritium BTW has a half life of only a handful of years which is why the old hand bearing compass you bought 30 or40 years ago is now hardly luminous at all.

The radium isotope OTOH has a half life of 1600 years