Using Expendables - Continued
(11) To lubricate, apply a thin, even film of silicone grease to the top of the caskets.
Figure 3-37. Applying Grease to Beaded Seal
Sealing Compound. Sealing compounds are used as a bonding agent to bond metal to metal or glass to
metal in optical or fire control instruments. It can be used to install gaskets, windows, lenses, and setscrews where a firm
air tight seal is necessary. Sealing compounds are divided into two categories, curing and non-curing. A curing type
sealing compound is made up of two individual agents, a base and an accelerator that are mixed together just before
using. A non-curing sealing compound contains one base agent, and does not require mixing prior to its use. The
removal and application of a curing type sealing compound is described as follows:
In steps (1) through (3), refer to figure 3-38.
Remove old sealing compound from the top of the setscrew, with a tool such as a scriber or jewelers
screwdriver. Loosen and dig out the old compound until the head of the setscrew can be seen.
If the setscrew begins to bind or get tight during removal, do not force it. Turn the setscrew
clockwise and then counterclockwise, trying to loosen the setscrew a few threads at a time until it
can be completely removed. It may be necessary to apply heat to the area around the setscrew to
loosen the sealing compound.