The Safe Handling of Optics: 5 Rules to Prevent Damage
One of the major challenges in repairing optical fire control is the safe handling of its optical components. Superior cleaning skills can take months or even years to master, but a few simple handling tips can prevent a novice from making an expensive mistake. The following five simple rules will help keep your optical elements usable and in serviceable condition.
Rule Number One: Touch the edges of the optics. Most lenses and prisms have a ground surface and a polished surface. The ground surface is rough and may be painted or remain untouched; this is a nonfunctional surface that can be safely handled without damaging the function of the optical element. The polished surface is smooth and shiny with a clear coating which helps transmit the light. This surface is extremely delicate and can be easily scratched or damaged by chemicals including the oil from our skin. This oil is acidic and over a short period of time, it will burn into the optical coating damaging the optics beyond repair. Human skin, even when washed, can also have dirt and grit on it which will permanently damage the polished surface of a lens or prism. When possible, wear rubber gloves or finger cots which can minimize the damage to the optics from our hands.
Rule Number Two: Handle the optics using soft or non-marring tools. Steel tweezers or forceps can easily scratch or damage the polished surface. A general rule to remember when handling optics is that when force is applied between a metal object and an optical element, the optical element will always give way and scratch or shatter. Wood or plastic tools are available from most industrial distributors and will greatly minimize the chances of damaging the optics. Another useful tool to have while installing or removing optics is a vacuum pump. Vacuum pumps come in various sizes and shapes but generally have a tube with a rubber cup at the end. When a vacuum is drawn, the rubber cup will hold the optic allowing it to be placed precisely and safely in any location.
Rule Number Three: Place optics on a soft surface. Placing optics on a hard or metal surface may damage the polished elements the same way a hard or metal tool will. The polished surface of most lenses is either flat, concave, or convex. Placing a concave element down on a soft surface will protect the delicate surface from being damaged. Placing the flat or convex surface down will directly expose the polished area, forcing all of the weight onto the optic, causing extensive damage. Recommended soft surfaces include, but are not limited to, clean paper, lens wrap tissue, toilet paper, and lens cleaning tissue. A backing of foam rubber under the tissue will offer additional protection in keeping the element safe from mechanical damage.
Rule Number Four: Cover optics when they are not being worked on. Even in a clean environment the air contains millions of dust particles. If your optics repair shop is in the same building as a machine shop or any other heavy equipment environment, there may be oil and coolant in the air. When they are not in use, place the optics in a bin and cover it with a fitted lid. If a bin is not available, place a sheet of lens wrap tissue over the optics to protect them from dust and other contamination. Another option is placing the optics in a closed cabinet. Exposure to contaminants can degrade the optics increasing assembly time and decreasing the quality of the finished instrument.
Rule Number Five: Store the optics properly. Be sure to wrap the cleaned optics in lens wrap or another soft tissue prior to storage. If the optics are in danger of mechanical damage during storage, wrap the optics with a secondary protection such as bubble wrap or corrugated paper. Bins with plastic separations will also provide protection against mechanical damage, but be sure to wrap the lenses in lens wrap prior to placing them into the bins.
Following these five simple rules will drastically decrease the possibility of damaging the optics and increase the chance of a successful build or repair.