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MICROSCOPE-ANTIQUES.COM     © 2013-15.


HOW TO RESTORE AN ANTIQUE MICROSCOPE: an introduction.

WARNINGS: Always wear face and eye protection when refinishing. The fumes of alcohol can be highly toxic-do not relacquer unless the area is well ventilated; outdoors is preferred if the weather permits. Relacquering cannot be done in cold air. Do not attempt to use machining equipment without all proper precautions. These machines, even small models, are extremely dangerous when not operated safely. When used without proper precautions serious injuries or even death are possible!

INITIAL CONSIDERATIONS:
Before starting any restoration on an antique microscope, carefully consider if this is appropriate. Firstly, antiques should not look new. If you want your microscope to look like new, go out and buy a new one. Simply restoring any antique to look like new when it is only slightly less than like new is not only inappropriate but will, in most cases, reduce the value of the instrument considerably. Before you start, know what you are getting into and what skills, tools, and supplies you will need. For instance, if there is an area that needs to be resilvered, you will need a simple method of doing this (usually a hand-held simple plating tool). You will need special screwdrivers, ground to fit all the old screws. You will need a very thin lacquer made from unwaxed shellac flakes, special brushes, and so on. You will need the skill to be able to brush on lacquer like it was done more than a century ago; spraying is not an option in most cases. You will need a camera to take detailed images as you take it apart, or you may not be able to get it back together! You will need a relatively dust-free but well- ventilated environment for relacquering and will need very high quality alcohol for this. Only if you are fully prepared, have time and patience will the project be a success.

CLEANING:
This is often, but not always, the first step. It may be all that is required; if an instrument has most of its lacquer and there is no really ugly spotting, it may be best to simply clean it. If only covered with dirt, simply using a damp cloth and cotton swabs and toothpicks(for very thin areas) will allow you to get rid of the dirt; do not soak it but use only what is needed. Often I see dirt assumed to be tarnish especially in tight spots on an instrument. Once this is done, dry it thoroughly and apply a coat of museum wax. This will suffice for many instruments.
If the cleaning step above is not sufficient, the next step would be a more thorough cleaning. For this, a reasonably safe cleaner is "Pre-Lim" available from the Gemmary and also other sites on the internet. This is a gentle brass cleaner that, if used gently and properly will not remove the character of the orignal finish and not cause the instrument to shine too brightly, thus looking "polished." It can even be used gently on some partly lacquered areas provided you are careful!. This cleaner will remove the worst of the tarnish however (but not some stains). This can then be followed after careful removal of the cleaner, with museum wax. Strong brass cleaners like "Brasso" should never be used for this step. I would only use something like "Brasso" if I were intending to relacquer to an original state. Even Brasso may not remove enough to prepare the brass for relacquering; in these cases, hand sanding, being careful not to round over sharp edges or remove machining marks will be needed (see below).

DISASSEMBLY:
Before going further, you must understand anything more than the above will require taking the microscope apart. You will need the proper tools and lots of notes and photographs to be able to assemble it all correctly later. Do not trust your memory! Proper tools will include most importantly, proper screwdrivers. Some helpful ones can be found in kits supplied by Gun dealers. Sometimes, you will simply need to grind your own. It is important to match both width and thickness to the slot in the screw, and never, ever, force it too much or you risk damage to the screw or even breakage of the screw. Use Kroil to loosen tight parts-it may need to sit over night and you may need more than one application. Some times you will need other special tools, like spanner wrenches, etc. Keep some tweezers handy for small parts. Also work over a place where if you drop a small part, it won't take an army to find it. Working over a carpet has advantages (it won't bounce), but the disadvantage that parts can get lost in the pile too. Use small cups with lids to store parts so they are not lost, damaged, or mislabeled. In some cases, some novel methods of assembly were used you may not be familiar with (such as a set-pin). When in doubt seek the help of an expert. Lastly, certain things are best NOT taken apart. An example is an iris diaphragm. These are extremely difficult to put back together. These parts I recommend you pass on and simply do the best you can. Lastly, some parts are so small you will need magnification to work on them-I use magnifying lenses on a headband and lots of extra light.

SANDING-MORE THAN CLEANING:
Remember you will need to take the microscope apart before any sanding! Sand only parts when separated. If sanding is needed, be prepared for a lot of hard work, usually by hand. Start with a relatively fine paper, depending on what is needed to remove the verdigris or stain. In some cases I start with 220 grit and then go to finer and finer papers or cloths. In some cases I start with 600 grit or even higher. Depending on the part you may need to stop with 600 grit or you may need to go even finer; the idea is to match the original. You may need cloth sanding pads up to 12,000 grit to achieve a polished finish in some cases. In the case of some parts it may be neccessary to buff to a high gloss-but only carefully, without harming the machining marks! Deciding what the original finish was like can often be gleaned from some remaining remnants of it, or found on another example of a similar microscope from a similar time period. Most importantly, in the case of straight pieces, the sanding cloth or paper needs to be supported on a block or other straight substrate to avoid rounding over straight edges. Unsupported paper is used only for round parts where it is needed to follow the curves. A buffed finish will sometimes require a buffing wheel-this is both tricky and dangerous. Use slowest speeds and be careful not to overdo it or damage the part or yourself! If you buff heavily over a signature or sharp edge, they will fade or worse, disappear, and the value of the piece will be shattered. The bottom line is that in these steps, less and slower are always better and safer. If you do not have the stamina or patience, simply do not restore instruments yourself. ALWAYS wear eye protection and face protection if using a buffing wheel or other electric machine.

REPLACEMENT PARTS:
Sometimes a piece is lacking all or part of a major component. This could be something as simple as a stage clip or as complex as the main optical tube and everything that goes with it. Obviously the more major the part missing the more difficult to replace. There are two options here. One is make the part from scratch, the other is find a spare part or one close to it and adapt it to your microscope. Finding these parts will not be easy, so do not count on being able to do it. Some people do this right and some who are inexperienced or just plain dishonest do it wrong. Replacing a 19th century lacquered brass mirror with black painted one obviously detracts from the instrument. If you cannot find a close match, or make one, it is probably better to leave that part missing. It is beyond the scope of this web site to show you how to make parts from scratch. Some people can do this using simple hand tools and a lot of hard manual work. Others have miniature machine shops or even a full size machine shop. Its just a question of learning how to make things. Rarely, you might find a machinest who is willing and able to make you a replacement part. But beware, most machinests are not familiar with the techniques needed for making these kinds of parts. They are often busy just making or repairing large parts for automobiles. They can also be expensive. People sometimes contact me asking if I have a spare part for their microscope. I do not have a stockpile of such items; the few I have I save for my own use and do not sell.

MACHINING NEW PARTS OR MODIFYING OTHERS:
Teaching machining is beyond the scope of this website. I recommend you find a friend who can help. I use a Sherline lathe and mill and have many of the Sherline accessories etc. Sherline produces a great book called Tabletop Machining; I highly recommend that book. Many of their accessories come with detailed instructions for use-read them!

RE-LAQUERING:
This is one of the trickiest things when it comes to restoring. The few professional restorers left on Earth often refuse to share their recipe for authentic lacquer. Modern lacquers are not really what was used. What was used was shellac. In order to do this properly you will need to:

  1. Have the proper consistency and color of lacquer-likely you will need to make this yourself from unwaxed shellac; modern pre-made lacquers are usually made with hazardous thinners and are seldom the color required; this is tedious and time consuming work. Very diluted solutions should be used in succesive coats. The brushing direction should be consistent. You will need to gently warm the part before applying the lacquer. I use a heat gun or hair dryer-KEEP AWAY from flammable liquids like the lacquer and alcohols. Keep track of amounts and types of ingredients you use; you will likely need to replicate it. Store unused lacquer in airtight containers in a cool dark place.
  2. Properly take your scope apart, noting carefully with notes and photographs how to put it back together. Only take apart what you need to to work on the part in question. Do not try to take everything apart all at once.
  3. Clean off the remnants of tarnish, stains, and old finish
  4. Sand the part in successively finer grits until you reach the finish appropriate for that part. Note this may be different for different parts and even from one microscope to another. Follow the sanding instructions above. Be sure to wipe off all debris and clean the part with alcohol immediately prior to reqlacuering.
  5. Refinish each part individually-using a very high quality brush(not available at your hardware store!) This will not looke right unless you use several thin coats rather than one thick one. Allow to dry between coats. If you make a mistake, simply remove the lacquer with alcohol.
  6. Reassemble after allowing suffient time to dry
  7. Properly lubricate the parts which need lubrication, but not the ones that do not. I often see a thin lubricant like oil used where a heavy grease is more appropriate, and the parts move in a unrealistic loose fashion.

Also note that some parts may have silvered scales and these will have to be restored as well after cleaning and before relacquering. Do not heavily sand any scales or you risk removing the engravings.

WARNINGS: Always wear face and eye protection when refinishing. The fumes of alcohol can be highly toxic-do not relacquer unless the area is well ventilated; outdoors is preferred if the weather permits. Relacquering cannot be done in cold air. Do not attempt to use machining equipment without all proper precautions. These machines, even small models, are extremely dangerous when not operated safely. When used without proper precautions serious injuries or even death are possible!