The arrangement of the fowc specimens is such that the two outside 

 specimen plates of each set are separated from the adjacent vinyl plate 

 by about l/2 inch and from the closest of the inside pair of specimen 

 plates by about 1 inch. The inside pair of specimen plates are separated 

 one from another by about SA of an inch. This arrangement is designed 

 to test the effects of the spacing of the plates (from each other and 

 from adjacnet materials) on the rate and on the degree as well as type 

 of deterioration of the plates. 



In each set of four replicate specimens ^ one plate has a 1-inch by 

 1-inch square "patch" of the same material bolted to it (as shown in 

 Figure l) by a nylon bolt. The purpose of this procedure is to investigate 

 the susceptibility of the material to crevice corrosion. 



Specimen identification code numbers are applied to all rigid 6- 

 inch by 12-inch specimens by a combination of two edge notches and two 

 l/8-inch holes which are drilled through the specimen at specific "grid 

 points." 



When the quantity of material available is insufficient for the 

 fabrication of 6-inch by 12-inch plates^, a specimen size of 1-inch by 

 6- inches is used. These specimen strips are fastened to a l/2 -inch- 

 thick polyethylene strip by means of l/4-inch-diameter nylon machine 

 screws. The specimens are spaced about l/8 inch from the polyethylene 

 strips by means of an acrylic washer » By using this method^ both rigid 

 and nonrigid materials are mounted for exposure. Fig^>ire 2 shows two 

 sets of the 1-inch by 2-inch racks installed on the Submersible Test 

 Unit. 



Short pieces of wire^ cable^ and rodlike specimens are held in 

 plastic mounting clips fastened to l/2 -inch-thick polyethylene strips 

 by means of 1/4- inch -diameter nylon machine screws. The polyethylene 

 strips are held in their racks by means of mild-steel bolts. 



Stressed Specimen Experiment 



Exposure to the experimental environment under stressed conditions 

 is accomplished in either of two ways according to the type of material. 

 Cables exposed in a stressed condition are placed in tension jigs 

 patterned after similar devices developed by the Anerican Steel & Wire 

 Company. Figure 3 shows a jig containing two specimens of cable iinder 

 tension. In use,, the cable is threaded through the jig end-plates and 

 tensioning screwj mild-steel end stops are swaged in place and the tension 

 screw is then adjusted using a cable tension indicator (see Figure k) 



