White mold? bacteria? fungus? in compasses

[AKuhlmann]

When the white stuff is there, is the bubble sometimes also present, or does it appear when the white stuff disappears?

The bubble grows when it disappears but tends not to be gone completely.

The theory of a reversible reaction so far makes the most sense

Just found this - admittedly it's from 2010:

https://forums.ybw.com/threads/silva-102b-h-compass-replacement-fluid.254566/

Thanks pwhole! That should help me repair them

 

[Cantclimbtom]

Ermm.. my current compass is a Silva because I was feeling tight fisted, but in the past I used good Suunto ones (even though their roamer scales were more suitably for US maps) because you could get oil filled ones not watery stuff. Oil is less prone to leak and bubble than cheap water (ones which might bubble even at moderate altitudes like >= 4,000m) The water based ones will always have a tendency to bubble more than oil