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TM 9-254
9-9.
Coating Optical Components - Continued
(29) Monitor SUBSTRATE TEMPERATURE GAUGE (2) until a temperature of approximately 200 degrees
Fahrenheit is obtained and then open SYS VENT valve (17) to release vacuum from bell jar (1).
(30) Place HOIST switch (22) in the UP position and allow bell jar (1) to raise completely.
WARNING
Protective gloves should be worn to prevent burn injuries when removing items from the bell jar.
(31) Remove holding fixture cover (2, fig. 9-31) from support ring (4, fig. 9-31) and cover lens elements with
batiste cloth.
(32) Remove holding fixture (3, fig. 9-31) from support ring (4, fig. 9-31) and place on a table to cool.
(33) Place HOIST switch (22) in the DOWN position and lower bell jar (1) completely.
9-10.
Cementing Optical Components.
WARNING
Use adhesives in a well ventilated area away from open flames. Adhesives are harmful to skin and
clothing, can burn easily, and may give off harmful vapor.
a.
Preparing the Cement. Optical cement is a thermosetting cement consisting of two parts, a polymerizable
resin mixture and a catalyst. Using an eye dropper mix 100 parts of HE-80, part A with 1 part of HE-80, part B into a glass
bottle. Using the eye dropper mix the two parts thoroughly.
b.
Cementing.
(1)
Remove matching set of lens elements from coating rack and remove all traces of dust and lint using a
watchmaker’s blower. If dust and lint cannot be removed by this method, clean the elements with
acetone and lens cleaning tissue.
(2)
Place the concave element on a piece of black felt paper with the concave surface up.
(3)
Apply optical cement to the center of the lens surface with an eyedropper. The amount of cement
needed will vary with the size of lens. Usually only a few drops of cement are required.
(4)
Make sure the matching convex element is clean and position it on the concave element. Apply a light
downward pressure to spread the cement evenly between the elements.
Change 2 9-34
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