Test Materials 



Test specimens numbering 2,385 items representing 603 materials were attached 

 to the STU for the exposure test. For evaluating deep-sea biological effects on non- 

 metallic specimens, two aluminum racks (bio-racks) were attached to the STU. Each 

 rack held several plastic rods and tubes 3 feet long, and a 12- by 30- by 1/8-inch 

 laminated phenolic plastic sheet. Numerous smaller test specimens were attached to 

 the plastic sheet; one sheet was secured to the upper section of a bio-rack, and an 

 identical sheet was secured to the bottom. In order to expose the test materials to 

 biodeterioration in mud as well as water, the two racks were attached to the STU so 

 that the lower portions would be buried in the bottom sediment and the upper portions 

 exposed to sea water about 3 feet above the mud line (Figure 5). 



The bio-rack specimens, listed in Appendix A, were carefully selected and 

 prepared for deep-sea exposure. The 2- by 6- by l/2-inch wood panels were cut from 

 sound lumber, and the surfaces were cleaned with an alcohol solution and then 

 covered with plastic to avoid contamination. The plastic covers were removed just 

 before the test specimens were submerged. The wood panels were employed to collect 

 specimens of any deep-sea fungi and marine borers which may have been present on 

 the ocean floor. 



The sections of the 3-foot-Iong plastic rods, tubes, and pipe, and rubber tubes 

 were treated in different ways. One section of each specimen was roughened, a 

 second section was wrapped in burlap, a third section was taped with plastic and 

 rubber electrical tape, and the fourth was left smooth. The various wrappings were 

 to provide a favorable foothold for the attachment and growth of deep-sea fouling 

 and boring organisms. A large piece of untreated fir wood was fitted around both 

 ends of each specimen to act as bait to attract and lead borers into direct contact 

 with the specimen materials. 



Four different kinds of rope, such as synthetic plastic fiber rope (nylon and 

 polypropylene) and natural fiber rope (cotton and Manila), were placed on the bio- 

 rocks. Electrical cables covered with rubber or plastic insulation of various thicknesses 

 were also placed on the racks. A small pine wood piece was fitted around each cable 

 specimen to act as bait for marine borers. Another group of electrical conductors 

 placed on the bio-racks consisted of 0.015-inch-thick insulation over a No. 16 tin- 

 coated copper wire. The materials used in the formulation of the insulation is presented 

 in Table II. The wire specimens were 15 inches long. Some were stressed (coiled) and 

 some were nonstressed (straight). Stress was applied by coiling a 15-inch specimen 

 lightly around a l/4-inch-diameter glass rod and then removing the rod. Both ends 

 of each specimen were sealed with two coats of rubber cement. The specimens were 

 positioned so that one set of ropes and electrical cables would be buried in the sedi- 

 ment (in which bacteria are ordinarily most active), and an identical set would be 

 exposed about 3 feet above the sediment. 



