Now allow to stand for 12 or 18 hours, then remove the mould from the block, the socket from the top of the mould, then gently push the roller out. If due precautions have been taken, it ought to come out quite smooth. If it does not, the composition must be melted off in hot water, and the roller recast.
Composition for the clearing roller—Scotch glue, 1 pound; gelatine, 2 pounds; green treacle, 1⁄2 pound; castor oil, 2 ounces; glycerine, 1 ounce.
The glue and gelatine are soaked as before, then melted and mixed with the other ingredients. The stock (covered with India-rubber sponge) is placed inside the greased mould, and the roller cast exactly as before.
The rollers being pushed out of the mould, trim the ends square with the ends of the stock, then dip the ends of each roller in hot water placed in a saucer to a depth of half an inch, until the composition is slightly softened. In this condition the sharp edges are rounded off with a damp cloth wound round the fingers.
The object of thus rounding the edges is to prevent the roller marking the picture when rolling up the image.
These rollers are not fit for use directly after casting, but should be placed on the handles, and washed with turpentine on a slab, then allowed to hang for two or three days, and occasionally washed over with a rag dipped in alcohol.
When in use the inking roller should never be washed, but if the ink upon it requires cleaning off, it should be done by rolling it upon a clean piece of hard paper. When put away after a job, the roller should be coated with fatty ink. Clear it for work next time by rolling it on the paper.
The clearing roller will require keeping free from a superfluity of ink by washing.
Instead of making the roller composition, and casting rollers, some of the high class composition sold for type printing may be used, or the rollers may be obtained ready cast, which will, perhaps, be found far more economical in the long run.