FORM WORK 333 



FORM WORK 



CONSTRUCTION AND FINISH OF FORM 

 WORK 



In the erection of reinforced-concrete work, nothing 

 requires more careful consideration than the construction 

 of the form work, or molds, necessary to shape and support 

 the concrete until it has thoroughly set and hardened. 

 Throughout the practice of reinforced-concrete construction 

 various methods of form constructions are in use. 



The greatest economy is gained by constructing the forms 

 so that they can be used over and over again in the structure. 

 Economy in construction can also be gained by fastening the 

 form work together with a minimum amount of nailing. 

 Every nail that is driven gives trouble when the forms are 

 taken down to be replaced for the upper floors. In many 

 constructions, wedges and clamps are used instead of nails 

 or screws if the forms are to be reused. 



In some instances, both wooden and metal forms are 

 coated on the side next to the concrete in order that the 

 forms may be detached more readily. Coating the forms 

 also serves to prevent the marking of the grain of the wooden 

 forms on the finished concrete work. 



Dead oil, or crude petroleum, has been used with success 

 for this purpose. It is not unusual to soap wooden forms, 

 and in some cases tallow and bacon fat have been employed. 

 The latter is especially recommended for coating metal 

 forms, as it seems to give the best results with forms of this 

 material. In some instances, wooden forms have been 

 covered on the inside with paper, and even canvas has been 

 used, although it is usually found that the paper adheres 

 to the concrete work and is detached only with difficulty. 

 It is not customary, however, to oil or coat the forms unless 

 they are to be used for fine exterior work. 



