I have a compas that my Uncle gave to me 45 years ago. He got it when he was in the CG during WWII on Cape Cod. He was a local lobsterman for about 60 years. Anyway the compass has lost about half the fluid in the compass. Also the gasket has deteriorated and it has corroded, which maybe the reason that it has leaked. What is the best way to repair it or is it better to bring it to a professional in the Portland, Oregon area?
One of the most important things you have to do is first determine what type of fluid the compass is filled/operates with. There are basically two types of fluid, one is waterbased, (sometimes with additional cleaning additives), and second is an oilbased fluid- It is essential that you find out which one it is, for the compass card markings are designed and made/painted on the card for only one type of fluid, and an oil based fluid added to a waterbased compass can rapidly remove/lift all the letters,marks & degrees. The other thing to note is that most, but not all, compasses have a bellows or diaphragm under the compass card. This diaphragm is basically designed to absorb the often possibly large variations in barometric pressure that any vessel voyaging offshore will encounter, and without which the air surrounding the inner compass parts could easily rupture the fluid bowl or gasket seal etc. This is very often the cause of leaks of fluid, along also with the gasket seal, so even if the gasket seal is repaired or replaced you must first be sure that the bellows or diaphragm is undamaged, before reassembly and refilling the fluid. Regarding the refilling, many compasses have a side entry screw fitting, with a washer/seal, for fluid top-up and refreshing. When I was working for a compass repairer and adjuster in Falmouth, UK, we used to make a small simple cradle to hold the compass bowl so that the fluid filling hole was absolutely vertical and theh used a small funnel to pour in the fluid, but then at the end we used a hypodermic syringe for the last part of the refilling process, as there will almost certainly be small air bubbles trapped inside the bowl near the filling orifice, and by forcing fluid only via the syringe needle, with the tip actually in the fluid, for the last filling, it should be possible to have every air bubble forced out, and the fluid must be literally brimming over the opening when you install the closing screw and (fibre) washer tight. We then used to place the compass in the domestic fridge for 24 hours, and any possible shrinkage of fluid and/or possible remaing bubbles of air become apparent, and a final top up by syringe may be necessary again. The reasons for the fridge technique is important, in that, naturally one cannot determine the actual atmospheric pressure or moisture cointent of the air at the time and place of refilling, and a very high or very low pressure will mean that there may be, more or less, moisture in the air at the time and which only becomes evident after cooling and stabilising the compass. Happy repairs- it is eminently possible to do it yourself ! sirphil