It is very essential to shellac or varnish wood patterns to keep them from absorbing moisture from the sand of the mould. This smooth coating also assists in drawing them from the mould.

After applying shellac or varnish, many shops paint patterns red for cast-iron castings and brown for steel castings. Core prints and core boxes are almost always painted black. Occasionally some part of a pattern is made merely to enable the pattern to be drawn from the mould and is not to be reproduced in the casting. Such a part is usually striped with black to designate to the moulder that the space it leaves in the mould is to be filled up with sand.

Patterns are too expensive to be thrown away when the castings desired are made from them. Each pattern should be marked or tagged with a number and its name, and should be stored in a store room where it can be readily found. A record book of patterns is kept to show, among other things, how many patterns are in a complete set for making, for example, the several castings of an engine.