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Patching and Finishing: After forms are removed, any 

 surfaces in the concrete not properly filled are to be gone 

 over with cement mortar and finished with a wood or cork 

 float, rubbed with stone, chipped, stuccoed or some other 

 manner. Frequently a tarred paint or waterproofing com- 

 pound is used. 



SPECIFICATIONS FOR ARTIFICIAL STONE. 



In making artificial stone the following specifications 

 should be followed: 



No concrete should be used that has been wet over 30 

 minutes. 



Proportion of water uniform. 



Thorough mixing, so that there is an absence of porosity 

 and permeability of block reduced by added density and 

 thereby overcoming efflorescence. 



Curing: In curing, the application of moisture should 

 be made regularly and uniformly so that the final set 

 may take place under the most favorable conditions, thus 

 insuring the greatest strength. 



Blocks treated with varying degrees of moisture or ex- 

 posure to the sun causing variation in contraction and 

 thus producing hair cracks should not be accepted. Blocks 

 or sections of molded stone should be sprinkled at regular 

 intervals and so frequently that no drying takes place. 

 They should not be allowed to turn white during curing. 

 Blocks made by the dry process should be carefully cured 

 for at least 20 days. Blocks made from a medium mix- 

 ture 7 to 10 days. When a wet mixture is used little water 

 will be necessary in curing, but uniform conditions must 

 be maintained and the stone sheltered from the sun. If 

 M .. us are cured in a live steam room same can be used 

 after 4 days. 



Facing: The facing of the blocks should be done with 

 a 1:2 mixture of cement and sharp fine white sand and 

 should be 1 in. in thickness. This facing should be ap- 

 plied before the backing takes its set and not be troweled 

 so that the neat cement is drawn to the surface and re- 

 sulting in hair cracks. In mixing, the facing should not 

 be allowed to become lumpy and the wet mixture should 

 be screened if necessary. A little more water than usual 

 should he used in the body of the block so as to insure 

 the moisture staying in the facing.. No interval of time 

 should elapse between the making of the body and the 



