Compass bubble

[pugwash]

There was a thread a while ago on this subject but it didn't reach any conclusion so I e-mailed the new makers of my old brass Sestrel compass and got a helpful reply in minutes. The fluid can be an alcohol/water mix (in which case a drop on a bit of paper evaporates) or it's a light oil called Bayol 35 (which has a smell). Mine is the latter and the stuff costs £12 a litre plus p&p etc. Two questions. What would happen if I tipped out all the fluid and replaced it with baby oil? If I buy the litre of Bayol I will use about one percent of it so does anybody want some?

 

[Guest]

Probably not a lot but

The liquid in a compass bowl his their to dampen the swing. How to check a good compass is to take a bearing on a point (any point) swinger the compass through 360 º and see how long it takes for the needle to stop at the correct bearing.
Traditionally compasses were filled with pure alcohol. Being the best anti-corrosion liquid combined with the ideal amount of suppression (four Swing) and of course being almost impossible without liquid oxygen to freeze.

-{)>

 

[kingfisher]

Keep the babyoil

Pour a few measures in the head once and a while. Best way to keep the pump going..

Obi-Wan

 

[Adrian_Morgan]

Tip: put compass afflicted with bubble in fridge, filler opening uppermost (having taken out filler plug first). Put compass fluid (when you've made up you mind what to use) in fridge also. Take out of fridge. Fill compass with fluid while both are still cold. Replace filler screw. Wait. Fluid warms and expands. Hey presto. No bubble. (Unless you happen to take compass to area where fridge is warmer than air temperature). Advice courtesy Sestrel themselves in instructions on how to assemble their hefty hand bearer.