CAVEATS

• Some steps in metal refinishing are rather prosaic. Stripping and sanding require some care but not significant technique. Spraying requires a technique that can be learned, partly by explanation and partly by experience. Unless you have developed this technique, subjecting valuable camera parts to sags, overspray and early peeling is a bad idea.
• Serious metal refinishing--the kind that good auto body shops do--involves expensive equipment, considerable training, controlled conditions, detailed knowledge and hazardous materials. With some care, you can do metal refinishing that is attractive, reasonably durable, and safe, using good quality spray cans in a clean and well ventilated area.

• Paint thinners--especially lacquer thinner--are very volatile and flammable. Use them in well-ventilated rooms and away from all ignition sources. Keep cans tightly capped. Do not store it near furnaces or other equipment with ignition devices.

• Some paint solvents--especially lacquer thinner--are dangerous when brought in contact with human skin and dangerous to breath. Read and follow all label instructions and warnings.
• Even with spray can materials--usually relatively safe--wear a mask over your nose and mouth to prevent inhaling airborne paint materials.
• When cleaning parts with thinners or strippers, wear safety glasses to protect your eyes, rubber gloves to protect your hands and a long-sleeve shirt to protect your arms from stray material.
• Small animals--for example cage birds and fish--are very sensitive to airborne chemicals. Don't use chemicals where fumes can reach them.

PREPARATION

• In good metal refinishing, you will spend 90% of task time in preparation. Accept it.
• 'Cleanliness' of prepared surfaces is essential to a durable finish. Any rust, oil or moisture on the surface of the workpiece will result in early failure of your paintwork.
• All existing paint must be soundly attached to the metal and all edges of existing paint must be sanded smooth or 'feathered' or they will show through your coatings as pock marks.

CLEANING THE METAL

• If possible, remove all metal to be refinished from the camera body. It is possible to mask areas, but it is difficult to prepare the surface as thoroughly when the area to be painted adjoins surfaces that could be damaged by solvents. Where masking is needed, for example in parts of a body casting that aren't painted, do your prep work first, then mask as the last step. Where complete disassembly isn't practical, you can carefully mask with masking of cello tape and protect larger areas with baggies, craft bags or newspaper.
• Remove all optics from metal parts and disassemble components.
• With small parts it may be easiest to strip them of existing paint. You can use a commercial paint stripper or soak them in a strong solvent like lacquer thinner.
• After you have softened the original finish remove all loose paint--an old toothbrush is good for small parts. Rinse the parts well in paint thinner (note that this is chemically very different from the lacquer thinner mentioned above). This is an inexpensive rinse material and it is compatible with the solvent base for most spraycan paint. Two or three rinses will insure that you have gotten all loose paint off. A safe and effective way to rinse small parts is to get a good quality plastic food container with a tight-fitting screwon lid. Put clean paint thinner and the parts into the plastic container. Make sure that the lid is tightly fastened and that no thinner is leaking out of the sealed container, then shake vigorously. Do not use lacquer thinner for this operation; it will dissolve plastics and is too volatile and dangerous to be used safely for this kind of operation.
• Finally dry the parts and inspect for any rust. If you find some, use a small wire brush to get down to bare, clean metal.
• If you have parts that have rusted, causing pitting in the metal, you can use zinc primer and sanding between coats to fill the pits and prepare a smoother surface. Sand with 200-400 grit wet-or-dry sandpaper, supported on a flat holder, especially for larger flat surfaces.

UNDERSTANDING SPRAYING TECHNIQUE

• Understand that getting a good sprayed finish requires considerable practice--you can't learn how to do this by only reading these instructions. If you have no or limited experience, practice on some expendable objects of about the same size and shape as the camera parts you expect to paint. Be confident in your abilities before attempting to paint valuable camera parts. Even if you do have experience, painting one test object with the current can of paint in the current atmospheric conditions will help you judge your painting activity when you paint the camera parts.
• Understanding how professionals paint will help you set up operations that reduce your chance of failure. The best paint locations have good ventilation with minimum dust--a conflicting set of conditions. Paint shops have paint booths with moderate air movement passed through effective air filtration systems that supply clean incoming air and eliminate the discharge of solids and toxic vehicle fumes. Professionals use toxic paint materials and wear special respirators that protect their breathing. You can begin to approximate these conditions by finding a relatively clean area--perhaps a garage with a clean floor. Spraying it with a fine mist of water will settle dust on the floor. Prepare a spraying area on a work surface well off the floor by spreading clean newspapers over an area that extends two feet beyond the surface of your workpiece. Support your workpiece vertically by some clean object that won't be damaged by overspray. Don't spray on a windy day; a dry sunny day is best. Remove any nearby items that could be damaged by overspray.
• Name brands of spray are probably better. The paint may be of higher quality and the nozzle may produce better results.
• The spray nozzle must be clean. If this is a new can of paint that will probably be true, but you should always spray a small test patch on a test surface. Holding the can upside down and spraying for a few seconds will clear the nozzle when you are finished. If paint accumulates on the nozzle, wipe it away with a rag moistened with a little thinner.
• Elevate pieces so that bottom edges don't stick to the newspaper covering your work surface. Use an item smaller than the workpiece to elevate it.

SPRAYING -- THE REAL THING

• Spray with the can in a nearly vertical position.
• Move the can horizontally, keeping it equidistant at about 12 inches from the workpiece.
• Start your spraying pass to one side of the workpiece and finish it beyond the other side of the workpiece--the paint spray pattern should be fully formed when you reach the leading edge of the piece.
• Move smoothly and evenly--never change your rate of movement or stop while the spray pattern is still aimed at the workpiece.
• Start at the top of each workpiece and work downward with successive passes.
• Spray three dimensional pieces from each direction. If the bottom of a piece, as well as its top and sides needs to be painted wait until those sides have dried completely before resting the piece on a newly painted surface to paint the bottom.
• It is easier to avoid runs on horizontal surfaces, but more difficult to get even coating if the area is very large. Horizontal surfaces also are more likely to accumulate dust as they dry.
• You will see that one pass produces a sprayed surface that is wet in the center and powdery at the periphery. You want to create a sprayed surface that has a uniform coating that is 'wet' across its complete surface. This is done by having the top edge of the workpiece in the 'wet' center area of your first pass. As you make successive overlapping passes, the powdery area at the top of each pass will be absorbed into the wet center of the preceding pass.
• Probably the most difficult area of judgment in spray painting is arriving at a balance of paint quantity in each coat. If you get the surface too wet, the paint will run; if your coating is to light, you will have a surface with a powdery character caused by overspray. This balance is affected by the paint material, atmospheric conditions and how the nozzle atomizes the paint material. There is no good way to describe this verbally--it is something you learn by trial and error.
• Don't try to coat too heavily. Several lighter coats are better than fewer heavy coats. Only the final coat will affect the smoothness of the surface, so erring on the side of overspray in initial coats is preferable to sags caused by too much paint.

DRYING AND CURING

• Follow instructions on the can for recoating. Drying time will be heavily dependent on air temperature and humidity
• Baking the paint will make it more durable. Baking at 200-250 degrees for several hours will harden the paint. Obviously this can only be done with metal parts that have no glass, leather or plastic components. Baking paint produces unpleasant and sometimes noxious fumes. If you have a small toaster oven that will operate reliably in this temperature range, taking it outside or into a garage will keep your house free from fumes.
• Allowing the paint to cure for several days before attempting reassembly will keep it from getting marred by handling.

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