Casts 



47 



light hammer should be used. The addition of color, such as 

 bluing, to the water when mixing plaster for either the mold or 

 the cast will be a help in differentiating one from the other dur- 

 ing the chipping process. Damage to the cast, by the chisel 

 biting in too deeply, will be lessened because it will be clearly 

 seen where the mold stops and the cast begins. 



The pectoral and ventral fins can be reproduced separately 

 in plaster, but I do not advise it; plaster fins, extending outward 

 from the body, are too fragile. It is preferable to replace these 



Fig. 46. Mako shark cast in plaster. 



fins with artificial ones carved ( a small electrical grinding tool 

 is best ) from sheet Celluloid or other plastic-like material. For 

 this method, cut the original fins from the body before molding; 

 then trace their outline onto the Celluloid with a sharp tool and 

 cut them out. A simpler method is to fold the fins against the 

 body, therefore including them in the mold. In other words, 

 the pectoral and ventral fins can be reproduced in plaster just 

 as they appeared folded against the body. 



If the cast is to appear as a whole fish, without a back or 

 plaque, avoid flowing the plaster onto the shelf of the mold 

 except in the areas containing the impressions of the tail and 

 fins. When the plaster starts to thicken, trowel more of it over 



