The fillets spoken of in connection with Fig. 179, are used in all except the most simple patterns. They consist of a small quarter curve varying in size from 1/8 inch radius upward, depending on the size of the pattern and the room they can be allowed to occupy. They should be placed in all corners, wherever possible, so that there may be no sudden changes in the direction of the surface of the casting, which causes weakness, the fillets adding greatly to the strength of the casting. These fillets are made in various ways, the wooden fillet, out as in Fig. 181, being commonly used for all long, straight angles, or for very flat curves to which it can be bent.
For irregular angles and for short radius curves, beeswax was formerly used, but the modern leather fillet has almost entirely superseded beeswax and other material for this purpose. It is easily applied, shaping and adapting itself to any and all positions and angles. It can be bought in all sizes from 1/8 inch up, the sizes running by sixteenths. The method of applying it is to cut it to the necessary length and lay it on a board where the glue can be easily brushed over it. It is then laid in the angle and rubbed into position by means of a dowel rod, the end of which must be rounded off as shown for the connecting dowel pins of a parted pattern, Fig. 152. The dowel rod must be of such size as to impart the required urve to the soft, pliable leather fillet. As soon as the fillet is ubbed into position all surplus glue must immediately be wiped off before it sets. This is easily done with a small piece of waste or a rag dipped in the hot water of the outer glue-pot and wrung out nearly dry, care being taken not to wet any part of the pattern more than can possibly be helped, after which it must at once be wiped dry.
These leather fillets will be found more pliable and more easily placed and rubbed into position if the glue used is first allowed to cool slightly. Very hot glue stiffens and crinkles the leather, causing it to work hard.