NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
From: Noell Wilson
Date: 2021 Sep 23, 08:57 -0700
Hi Paul,
I don’t think the refractive index of the fluid matters on the A-12 since you look at the bubble instead of through it - see photo.
Xylene is easy to get from a paint supply store in the U.S. Although it’s volatile, it leaks/evaporates without leaving any residue.
A plastic hypodermic works well for xylene if you rinse it with water and open it to dry.
Alcohol supposedly dissolves the lacquer used for sealing some bubble chambers. Wood alcohol is really bad for humans. Isopropanol is not good. Ethanol is ok if used in moderation. Seals aside, alcohols leak without being messy.
I’ve tried baby oil and, when it leaks, it leaves a mess.
Other petroleum spirits like kerosene, mineral spirits, etc. tend to leave a slight oily residue.
Regards, Noell
