NavList:

I've been having a great time learning to run my Kollsman bubble sextant (MS 28011-5) and getting very nice results from it on stars and sun.  I recently bought another one for spare parts and, upon inspection, found that everything on it, even the pellicle, is working - except for the bubble chamber.  There is no fluid in the chamber.  Since one is none, I'd rather like to get this one running by fixing up its bubble chamber.

I understand that the Kollsmans used silicone oil.  It appears that such a substance can be found on Amazon.

I found a sextant repair manual however it does not include any details on how one fills the chamber.

I did a search here for the Kollsman bubble chambers but did not find anything.

Does anyone know how to refill these bubble chambers?

Thanks

-- Arthur