Liquid in Plastimo Hand Bearing Compass

[Pagan]

I have been given a, working, Plastimo (SNP 73 this is the only number I can find) hand bearing compass with a bubble, there IS a facility for topping it up.

Can any one tell what is the best liquid for topping up or indeed filling should I empty it of its contents completely.

It smells like it has Turps or similar in it at the moment which I suppose could have evapourated....

I can detect no damage or obvious leak except possibly at the filling screw where it has a rubber grommet.

Many Thanks
Pagan (Nev)

[GordMay]

I think you'll have to contact Plastimo.

Until recently, most compasses used Odourless Mineral Spirits as their damping fluid.
Ritchie (for one) now uses a fluid called Isopar L ® (*1) that has similar properties, but with some added benefits over Odourless Mineral Spirits. The two can be mixed together.

(*1) Isopar L® is a Registered Trademark of Exxon Mobil Corporation - generically known as: Isoparaffinic hydrocarbons (Isoparaffin), Hydroheated heavy naphtha (petroleum).

Some compasses are filled with mineral oil. Baby oil is mineral oil, although it often has other additives, like perfumes.

Some older style (up to 1960's) Compasses used an Isopropyl Alcohol and water mix, or Kerosene.

See the (unhelpful) PLASTIMO FAQ:
➥ Plastimo: boat equipment – FAQ - Technical support

Plastimo Compass Instructions
➥ http://www.plastimo.com/pdf/compass_inst%28uk%29.pdf

[Badsanta]

I thought a bubble was supposed to be there. But I dont know why.

[GordMay]

Originally Posted by Badsanta

I thought a bubble was supposed to be there. But I dont know why.

From the Plastimo FAQ:

"The cell of the Plastimo compasses is designed to be completely fluid filled. If you see a permanent bubble, in a temperature range from –20° to +60°C, it means that your compass is leaking (as the fluid tends to evaporate, you may not have noticed the leak). Contact our after-sales department for advice."

[Pagan]

Thanks to all responders.

I have filled it with Johnsons' baby oil and will see how that goes, will report back in due course.

I tried to give thanks to Gord-May but it wouldn't let me. Does it know something I don't !

Nev