the type of truck which can transport at the same time the other items essential to 

 the operation. Figure 7 shows equipment mounted on a Navy truck. 



Where operation is confined to a single group of warehouses, or to several 

 groups in a small area, the trailer-type compressor can be used to advantage. This 

 type of equipment can often be moved to positions under the shed roofs of the 

 warehouses or to other more convenient locations, thereby eliminating the need 

 for excessive footage of hose. However, compressors should at all times be placed 

 in the open air outside the building to be sealed. 



Where compressed air is available from a stationary unit, it is desirable to have 

 outlets arranged so that the hose will not be more than 100 feet long in any 

 location. Nozzle pressure is important and is difficult to maintain when longer 

 hose is used. 



Spray-Equipment Requirements 



Equipment required for the application of plastic material is basically that used 

 for spraying paint and other viscous substances. Manufacturers of equipment 

 listed by the Navy in their publication on OS-3602 are the DeVilbiss Co., Toledo, 

 Ohio, and Binks Manufacturing Co., Chicago, 111. 



The products of these manufacturers have been thoroughly tested and meet 

 the requirements of this type of spraying. Other manufacturers produce similar 

 equipment. In the selection of these items, however, it should be noted that the 

 material to be sprayed is viscous and of relatively heavy body. Nozzles, spray 

 guns, and pressure pots should be selected on the basis of their adaptability to the 

 use of plastic. 



All of the spray equipment tested in the experiments by the Department was of 

 a standard type and readily obtainable. The equipment required for the two- 

 man operation recommended is shown in the following list: 



Four 10-gallon pressure feed tanks, 2 equipped with agitator (2 for plastic coating and 2 for 



webbing solution). 

 Two 2-gallon pressure feed tanks (for adhesive or webbing solution). 

 Six spray guns (2 for vinylite plastic, 2 for webbing, and 2 for adhesive material). 

 Twelve 50-foot lengths of /4-inch fluid hose (pressure pot to spray gun). 

 Twelve 50-foot lengths of %6-hich air hose (pressure pot to spray gun). 

 Twelve 25-foot lengths of 7 /iQ-'mch air hose (compressor to pressure pot). 

 One air regulator. 



One air motor (for use on agitator). 

 One compressor (approximately 100 cubic feet per minute). 



Cost of Equipment 



With prices prevailing at the time of the experimental work, it was found that 

 the approximate total cost of the spray equipment required for this operation 

 would be $1,430. A compressor of the type used was priced at $2,500. The 

 combined cost of these items represents a sizable investment, but it must be 

 recognized that this equipment will last almost indefinitely and that with minor 

 repairs and the replacement of some hose, a life of 20 years could be expected. 

 Prorating the cost over this period would bring this item into proper perspective. 

 This scale of depreciation is based on the assumption that the outfit will be used 

 for not more than 6 months in any one year. 



Requirements for Small Operation 



In the event that the user of plastic has only a few storage sections to seal or if 

 unlimited time is available in which sealing may be accomplished for a larger 

 operation, a smaller unit (figure 8) than the one previously described may be con- 

 sidered. This smaller unit, operated by one man, would need a small-type com- 



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