Page:Cyclopedia of Painting-Armstrong, George D (1908).djvu/408

400 Paint must be kept of a uniform consistency to give uniform results.

Where japan is used, always get the best and use it sparingly. Never add japan last or after the mixture has been thinned down.

An excess of japan will keep the paint from hardening and make spongy work.

There are very few exceptions to the statement that boiled linseed oil should never be used for undercoatings.

Always use pure raw linseed oil for reducing paints. Insist on having the best. See that it bears the brand of some reputable oil crusher.

There are no substitutes for linseed oil.

An excess of oil in the middle coat on new work and first coat on old work will retard the hardening and cause the finishing coat to flatten out, also very apt to cause blistering.

Tacky Paint. This is more often caused through improper application of the undercoats than through any fault of the paint.

Paint, varnish, or a similar product applied over a glossy surface or a surface which is not hard dry is much more likely to remain tacky than if applied over a thoroughly dry, half flat or flat surface.

Some paint pigments are natural dryers, while others are non-dryers. The non-drying pigments, when used in painting, if not properly prepared and applied over a suitable surface, are very apt to dry tacky and remain so.

Varnish added to oil paint will cause the paint to remain tacky. Colors in oil mixed with varnish will not harden, but soften under exposure to heat.

Always prime a building before the plasterer commences his work.

Never second or third coat a building while the plaster is drying out. A building should never be tightly closed while the plaster is drying out.