Refilling a compass

[cliff]

What ever fluid you chose to use do vacuum degas it before use or you will have bubbles forming sooner or later - usually sooner.

 

[sailorman]

If a compass requires a top-up then fix the underlying problem first. normally a diaghram leaking or getting weak

 

[Big John]

I've done a couple of small ones - white spirit has seemed fine. However - be prepared to totally immerse the compass in the fluid if you don't want a real hassel with that last little bubble !
Also - although white spirit is pretty mild stuff, when you totally immerse both hands in it, it gets a bit twitchy. Wear some gloves :ambivalence:

Is the bubble not there so as to allow expansion of the fluid when the compass heats up in the sun? If there is no bubble the fluid will exert pressure on the body of the compass and find the weakest point and split.

 

[alahol2]

Is the bubble not there so as to allow expansion of the fluid when the compass heats up in the sun? If there is no bubble the fluid will exert pressure on the body of the compass and find the weakest point and split.

That's the optimistic way to look at it. Unfortunately no compass is designed to contain a bubble. All liquid filled compasses have a flexible diaphragm which allows for the expansion/contraction of the liquid.

 

[sailorman]

Is the bubble not there so as to allow expansion of the fluid when the compass heats up in the sun? If there is no bubble the fluid will exert pressure on the body of the compass and find the weakest point and split.

No, that's the diagrams job

 

[antaris]

In the past, I have filled two compasses with Johnson's Baby Oil. Both worked and lived to tell the story (and the correct bearing) . I would hate to have some flammable fluid leaking onto the deck...

 

[nortada]

Thank you all for all of the very helpful advice.

The compass is an Olympic 135. I have removed the base but so far haven't found the replenishment point? Help!

 

[sailorman]

Send it away for a proper pro repair

 

[Alfie168]

I have my Grandads small wartime compass that sat on his desk on the MV Britannic. No idea what make. It just says Made in USA stamped on the bottom of the cast bowl and the the number 43- which may refer to the date, but i'd expect it to be earlier. It should be in gimbals and has two screws which I assume are to correct the deviation. Its a little gem really and I bet if it could talk it could tell a story or two. Its not in brilliant condition and could do with some proper conservation. I'm not sure the next generation is that interested in the fact it sailed round the oceans throughout WW2 and survived.

Tim

 

[sailorman]

I have my Grandads small wartime compass that sat on his desk on the MV Britannic. No idea what make. It just says Made in USA stamped on the bottom of the cast bowl and the the number 43- which may refer to the date, but i'd expect it to be earlier. It should be in gimbals and has two screws which I assume are to correct the deviation. Its a little gem really and I bet if it could talk it could tell a story or two. Its not in brilliant condition and could do with some proper conservation. I'm not sure the next generation is that interested in the fact it sailed round the oceans throughout WW2 and survived.

Tim

We only paid for it 3 yrs ago Tim

 

[ceproof87]

It's a simple process. You have to just open a container of compass oil after that fill a manual industrial syringe with oil and then insert the syring in fill hole of the compass.

 

[Norman_E]

How do I replenish the oil in a Plastimo Olympic 135 steering compass? i.e. where is the replenishment screw and how much stripping down to I have to do.

White spirit appears to the preferred fluid?

Must already be a thread/post covering this so just please point me at it.

Ta

I wrote an article for PBO on topping up that type of compass. It is in the January 2014 issue. I used Johnsons Baby Oil and the compass took over a litre of it. The filling screw was sealed in manufacture by melting plastic over it. It is easy to see where it is, You have to very carefully drill away the plastic covering the screw head.

 

[sailorman]

I wrote an article for PBO on topping up that type of compass. It is in the January 2014 issue. I used Johnsons Baby Oil and the compass took over a litre of it. The filling screw was sealed in manufacture by melting plastic over it. It is easy to see where it is, You have to very carefully drill away the plastic covering the screw head.

If it took a Ltr where did the original Ltr go

 

[Norman_E]

Read the article. I had two compasses. I emptied the port compass and refilled with Baby Oil. The oil from the port compass topped up the starboard one.

I am reminded that Johnson's Baby Oil contains liquid paraffin and isopropyl palmitate, the latter being a blend of isopropyl alcohol and palm oil. If you are in the UK don't buy baby oil, just go to a chemist and buy liquid paraffin BP, as you don't need the other ingredients.

 

[sailorman]

did they leak after at any time

 

[Norman_E]

did they leak after at any time

Not yet.

 

[Bi111ion]

My Sestrel



I bought this compass in a junk shop when I was a teenager in the hope that one day I would have a boat big enough for it to go in. I have the boat but it came with a compass! Anyway the fluid is water + ethanol and it mixes very nicely with gin so I have got rid of the bubble.

The Gin also mixes nicely with tonic water. Cheers!