compass fluid

[neil_s]

Hi there!

Anybody know what I can top up my compass with? The recent warm weather produced an aromatic damp patch on the bulkhead underneath my Plastimo Contest and a rapidly growing air bubble. The leak seems to be around the sealing screw, which was very lightly done up, so I think I could re-fill the compass and all will be well. The fluid smells a bit like turpentine.

Cheers! Neil

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[Avocet]

I recently read about someone using baby oil but I don't know what sort of compass it was.

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[Rosa]

Used baby oil in my Plastimo (Tesco's was fine)
First I contacted Plastimo who weren't able to identify the fluid.
Didn't smell like alcohol (and seemed a waste of good gin!) so tried cheap Baby Oil.
Worked a treat.

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[nickjaxe]

I used baby oil but had to thin it down with white spirit the oil was a bit to thick, to put it in I had to drill a small hole in the dome of my compass, plug it with a copper rivit head just dropped in loose.

Nick in runcorn.

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[alanporter]

A special thin oil is what most compass makers put in, but over the years I have used pure methyl alcohol or kerosene (paraffin in the UK).. Rather than trying to fill the compass through the plug hole, which always leaves a tiny bubble, I immersed it completely in a bucket of the liquid while I screwed the plug back in. This works very well and is cheap.

<hr width=100% size=1>Alan Porter

 

[jollyjacktar]

Be careful, some plastic thinghies, will disintegrate if you use an alcohol base. I think Plastimo was the brand that I tried it on [it was filled by a professional???!!! compass repairer], plastic crazed, the joints split open and before all this happened, the effect of the wrong fluid buing used changed the refractive index and the scales etc could not be read through the prisms etc. This should have been warning enpough, however fools rush in wheere angels fear to tread. I now have a pile of collectors scrap and have purchased another handheld compass, a new SILVA.

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[steve_cronin]

danforth use \"Aeroshell\"

I researched this a few years back and found out that they use a jet engine lubricant called Aeroshell 80. (subsequently found this info on a label on the bottom of the compass!)

I eventually got a supply from a local regional airport with the bribe of a bottle of scotch. However now, CAA regulations require the accounting for of every drop of maintenance materials so it might not be so easy. Maybe shell themselves might be able to help?

Steve Cronin

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[vyv_cox]

Re: danforth use \"Aeroshell\"

Aeroshell 80 is a mineral SAE40 aero piston engine crankcase lubricant. Its colouris stated to be ASTM 4 but I don't know the meaning of this.

A white paraffinic oil was used in the Plastimo compass that I refilled some years ago. Not sure of the composition of baby oil, I used a special boiling point liquid similar to kerosene.

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[jsl]

Quite so: my old Sestrel takes alchohol. Suppliers are SIRS Navigation: www.sirs.co.uk

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[jeanne]

we have used liquid paraffin from any chemist. seems to work well

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[neil_s]

Many thanks for the replies! I have been doing a bit of surfing during the day and found many American compass topper uppers were using what they call mineral spirit (white spirit to us). The fluid in my Contest smells more like paraffin, so I shall use that. Incidentally, the plastic dome on my compass polished up a treat using Brasso. The reference to sirs is useful, because I also have an old Sestrel Minor in the loft which deserves better.

Good sailing! Neil

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[VicS]

We used to regularly top up the leaky compass in an old Sea Course with medicinal liquid paraffin but it eventually became too sluggish so we started using barbeque lighting fluid, which the analytical chemistry lab reckoned was practically identical to paraffin. Later we found that the instruction book actually said it was filled with white spirit so now we use that.

Add what ever you choose to use slowly and watch it mix with the original. If youve got it right you wont see them mix (because theres no difference in refractive index). If youve got it horribly wrong they might not mix at all! A hyperdermic syringe is the ideal tool to use if the hole is small.

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[jmp]

Most compasses nowdays I beleive contain bay oil .I have been informed by several repair firms who also will sell the product.It is produced from bay trees.

I have myself topped up a mini 2000 handbearing ,which I was told to scrap 2years ago, which is still as good as new.Also a plastimo contest(20 yrs old) 1year ago.

Both were topped with white spirit ,as my sense of smell and a mixing test seemed a good risk on two units at least 20 yrs old .

Both are so far as good as new ,and have justified my gamble .

Best of luck .

Michael

<hr width=100% size=1>jmp

 

[mikw]

It may seem a waste, but Gin will do no harm. If you are lost at sea you can always break the bowl and drink the contents! However it is a good substitue for the alcohol mixture used by the manufacturers.

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[samuel]

I have had my Sestral grid steering compass for 35 years & when I bought it the manufacturer included refilling instructions which was to use white spirit.
By the way ,, why is it you cannot seem to buy a grid steering compass easily these days???
With a modern compass the rolling of the boat makes the numbers roll & apart from the strain on the eyes a tired helm can forget what course he should be steering. ( Well I used to anyway !!) One of my most valued boat accessories is my Sestral grid compass. I set the course and can steer far easier with it. Plus I can see it from a range of angles which helps if I am sitting out on either the weather or leaward deck. Surely it is not that much dearer to manufacture.

<hr width=100% size=1>Justisla

 

[neil_s]

I have used ordinary clear paraffin (bought from the garage) to top up my plastimo Contest. It was rather more than topping up, though, since I had lost about one third of the fluid. The result seems OK, although I did notice visible 'swirling' in the liquid for a moment as I squirted the paraffin in. I guess this means, as you point out, that there is a difference in the refractive index of the two fluids. Time will tell!

Thanks to all for your postings

Neil

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