Paul restoring a Stanley MkIII Liquid Prismatic Compass
There is much discussion and controversy as to whether one should "restore" old scientific instruments or leave them with their patina, their badge of age and supposed "use".
My personal opinion is that a small amount of patina signifies use, but a lot of patina signifies neglect. This opinion, however, is not shared by everybody.
When you buy a classic wrist watch such as a Patek Philippe, to name just one example, the retailer will recommend you send it back for annual servicing and while it is being serviced they also clean the watch and polish out any scratches and make any necessary repairs. I believe that the same principle should be applied to scientific instruments, especially as not so long ago a chronometer such as a Patek Philippe would have been very much regarded as a scientific instrument.
Veteran, vintage and antique motor cars and motorcycles are always restored to as near concourse condition as possible, and no criticism is made that such restoration takes away the "patina" and decreases the value.
Where necessary I clean, restore, repair and refurbish many of the antique scientific instruments I buy and I put them into full working condition as they were made to be. My feeling is that these instruments were not made to put under glass and develop a patina of disuse or misuse, but were made to be used and loved, and to withstand hundreds of years of use.
Brass looks beautiful when cleaned. If the original makers had tried to sell their items already dulled and bearing the patina of time they would not have been very successful. People bought the instruments for many reasons, but one reason was that they looked impressive, all shiny wood, brass and glass.
I think it is a very sad sight to see excessive patina, and I have no problem stating publicly that the first thing I do when I get my hands on a 200 year old telescope, compass or other scientific instrument, is to assess it carefully and decide if the patina is actually really patina or if it is a sign of neglect. If the original lacquer is scabby and unsighly I have no problem removing it and polishing the brass. Sometimes I re-lacquer the item, other times I let the brass develop a slight patina, but then clean it regularly with alcohol to maintain a nice colour.
Re-lacquering is not difficult. There are modern two-part epoxy lacquers that work beautifully; or you can mix up some original 19th century lacquer, the recipes for which can be found in the Internet and in several publications, and try it yourself. Brass is resilient and if you get it wrong you just remove the lacquer and try again in a different way. Never be afraid to experiment, though experiments are best carried out on an old piece of brass that has no value.
Many antique collectors and dealers will tell you that it is sacrilege to clean and restore, and maybe they have a point, but personally I disagree with them and thoroughly enjoy having a fully serviced, fully functional and very beautiful instrument that draws attention and encourages conversation, much like an eighty year-old car in concourse condition, or an old Patek. Nobody EVER lets a wristwatch develop a patina, so why are opinions so contradictory for antique scientific instruments?
Obviously if one finds an almost pristine antique instrument then it should be enjoyed without tampering. When, however, time has taken its toll on a 100, 200 or even 300 year-old instrument, then careful cleaning, repairing and restoration, in my opinion, is not just acceptable, but a duty.
The choice of whether to restore or not lies with the owner of the item, but they should read as many books and take as much advice as possible before embarking on a cleaning or restoration, or even consider having it done professionally if the item is of high financial or emotional value, or if the item contains Radium paint.
Replacing broken glass is not difficult these days. Watchmakers usually have watch crystals of all shapes and sizes and it is usually fairly easy to find one. Lenses can be made up by any High Street optician. I have asked them in the past and although their initial response was "I don't think so", they were kind enough to make enquiries and in the end were happy to do the work.
Old missing brass screws and many small parts can be found in modelling shops and available by mail order from many model maker's magazines.
Missing or damaged Morocco leather can be replaced by buying old, empty instrument cases at low prices in Ebay or at markets and stripping the leather off for future use, or by scanning the item with a colour computer scanner and then printing the scan onto paper. The paper is cut to size and glued on, having the same colour and pattern as the surrounding leather.
Many of the parts of the Mk III and even earlier compasses can be adapted from spare parts made specifically for the modern Francis Barker M73 or the now discontinued Stanley G150 compasses, especially the sealing gaskets. If the compass requires a smaller sealing gasket then simply cut a section out of an M73 or G150 gasket and bring the ends together with silicone adhesive. Beware however that the modern gaskets are thicker than the old ones, and when you screw down the clamping ring you must not tighten the screws too much, so that a gap remains between the clamping ring and its seat, or the screws will simply strip their threads.
Any compasses or wristwatches manufactured prior to the mid 1960s will probably contain Radium paint used for the luminescence for night use. If your compass has thick brown, red or pinkish marks on the dial then it can be assumed it contains Radium and should not be opened. Please read the Compass Repairs section of this website.
