Compass Air Bubble

[Guest]

My compass has a large air bubble which I wish to eliminate. What liquid should I inject in for top up purposes?
I intend to drill a small hole in the top of it, inject the liquid, and then close off the the hole with silicone sealant.
Can anyone help me please?
Thanks.

David

 

[AndrewB]

Various liquids are used. Alcohol is now rare, most are light oil based. DON'T mix them.

Many makers will advise and supply small quantities of the correct fluid. Alternatively, a Compass Adjuster will be able to top it up for you.

If you decide to do this yourself, and you are still guessing what is used, I suggest you run off a small quantity and try mixing it with whatever you propose to top up with, to make sure they will in fact mix. If the compass liquid is oily, regular Baby Oil is worth a try.

There is no need to drill a hole in the top. There is always a filling hole, normally on the base, sometimes the side.

 

[pvb]

You\'ll be wasting your time...

If your compass has an air bubble, it indicates there's a leak - probably in the expansion bellows. Unless you fix the leak first, topping up the fluid is a complete waste of time. Suggest you take it to a compass repairer.

 

[Guest]

Can't help you on oil type, but I repaired my compass. The bellows will most probally have a small split which is very hard to find. I suggest that you drain the oil via the small screw on side or bottom then find leak and solder with standard soldering iron and flux. Refill and this should do you.

 

[Guest]

oil type

I was confronted with the same problem a couple of months ago... Apparantly a regularily used oil type is "Esso Bayol, grade 35". This oil is used in the food production industry, and is completely colourless, odourless and tasteless (i didn't try!). For smallish bubbles you can use regular white spirit.

To get the compass as full as possible:
1. fill the compass as full as you can get it
2. put compass and oil in the fridge overnight
3. top up compass
By doing this I managed to eliminate the complete airbubble, but patience is the trick here. The bubble only disappears after a couple of days, when the liquid has fully warmed up. Use a hypodermic syringe to do the topping up with. Succes!

 

[AndrewB]

Using the fridge.

If you chill it really cold for refilling don't you end up putting too much pressure on the bellows in hot weatherl?

I thought about doing this when I refilled mine following a joint weep (cured with 'Creeping Crack Cure') but decided against. There is still a bit of a bubble in cold weather though.