62 SILOS: CONSTRUCTION AND SERVICE 



actual use to compare them intelligently. In addition to 

 this there are several types of homemade forms, all of which 

 have been quite thoroughly tried out. The first is taken 

 from Bulletin 100 of the Iowa agricultural experiment station. 

 Illustrations of these forms are shown in Fig. 16; the descrip- 

 tions are taken from the bulletin. 



"These forms resemble those used by R. L. Sollet, of 

 Goldfield, Iowa, in the construction of his silos. Two sec- 

 tions of staves 30 inches long are held in place by wooden 

 hoops made of ^ to J^-inch lumber bent to the proper circle 

 and nailed firmly together. 



"The staves rest on %-inch square cleats nailed to the 

 hoops. The inner hoops are made solid ; and to remove them, 

 one side is driven down and the hoops sprung out of round. 

 The outside hoops are made with clamps by which they may 

 be opened for removal as shown. Three outside and three 

 inside hoops are required. The purpose of having two sec- 

 tions of forms is twofold. First, the second set of forms is 

 accurately located by the first before the second is moved, 

 and also by using 30-inch staves 5 feet of wall may be built 

 each day and the form need not be disturbed until the con- 

 tained wall is at least 18 hours old. Second, no tamping of 

 fresh concrete occurs on the unsupported wall, as there is 

 always a section of the forms below the one being filled. The 

 30-inch stave length was chosen because longer staves are 

 likely to bend, and the length is handy for fitting the doors, 

 which are 30 inches high inside and placed 30 inches apart." 



The same staves will serve for any diameter of silo and 

 the hoops can be made adjustable within a limited range, so 

 that a few sets of hoops will equip a contractor for any diam- 

 eter of silo. This system of forms has been found to be fully 

 as cheap as any. 



