PHENOLIC AND PLASTIC MATERIALS
5-1. General. Identification, usage, and storage of phenolic compositions and plastic materials are explained in the
5-2. Phenolic Compositions . Identification, usage, and storage is as follows.
Identification. The manufacturer will mark each full size sheet on the right-hand corner, on both sides, with name
and trademark and type FBG (General purpose grade). Phenolic sheets, MIL-P-15035, are actually cotton-fabric-base,
phenolic-resin laminated thermosetting sheets.
Usage. Phenolic sheet is used to make chafing strips, dividers, spacers, fillers, fairleads, and washers. Unless
otherwise specified, phenolic compositions should be attached with rivets.
Storage. Store phenolic composition sheets in a cool, dry area. Wrap or interweave sheets with 25-pound
wrapping paper, Federal Specification UU-P- 268.
5-3. Plastic Materials. Identification, types, and storage of plastic materials are explained in the following paragraphs.
Identification. Plastic materials, including grades and intended uses, are listed in Table 5-1. Some plastic
materials may be identified by information marked on protective covering as follows:
Specification number and type.
Manufacturer's code designation
Types. Some of the various types of plastic materials which are used in Army aircraft are explained in the
(1) Thermosetting. Thermosetting plastic, MIL-P-8257, can be heated and molded only once. When viewed
from the edge, this material has a bluish or blue-green tint.
(2) Craze-resistant acrylic. Craze-resistant acrylic plastic, MIL-P-8184, is used on newer aircraft or in parts
fabricated since 1953. When viewed from the edge, this material has a slight yellowish tint.
(3) Laminated plastics. Laminated plastics, MIL-P-25374, is composed of two layers of craze-resistant acrylic
plastic, MIL-P-8184, bonded together with a soft plastic inner layer.
When tapped lightly with a small blunt instrument, plastic resounds with a dull or soft
sound while plate glass resounds with a metallic sound or ring.
Storage. Store plastic materials in a cool, dry area away from solvent and paint fumes, and not exposed to direct
rays of the sun.
When masking paper adhesive deteriorates, moisten the paper with aliphatic naphtha,
Federal Specification TT-N-95 Type II, only. Wash sheets immediately with clear water.
Observe all dire pre-cautions while using aliphatic naphtha for cleaning acrylic plastic
injury to personnel may otherwise result.