Page:Cyclopedia of Painting-Armstrong, George D (1908).djvu/153

Rh been applied too heavy and upon examination is found to be perfectly bound to the wood, it can be successfully repainted in the following manner:

A great deal of care should be taken in the preparation of the first coat, as the surface is usually hard and brittle. If the paint is mixed half flat it will have sufficient turpentine to penetrate well into the undercoats, and if well brushed will thoroughly bind to them.

The finishing coat should be of good consistency and well brushed. It should contain from 1-32 to 1-16 gallon of turpentine to a gallon of paint, as the paint should nut be too elastic, otherwise it is liable to blister on this hard surface if exposed to heat when fresh.

Paint found to be cracked only through the top coat, the checks not running through to the work, makes a very treacherous surface to repaint, as the first coat applied is liable to penetrate only through the hard glaze which has already commenced to crack and possibly breaking loose from the undercoats, and when a second and more elastic coat has been applied this glaze will break loose and cause the last coats to peel. The first coat should be mixed with $1/4$ gallon of turpentine to the gallon of paint, so as to penetrate, if possible, the glazy surface to the undercoats which are more firm, thereby binding itself as well as the finishing coat to the surface. The finishing coat should not be applied too elastic. This is to avoid having an excess of oil on the surface.

Large and deep cracks, running to the primer or undercoats, are usually caused by coats being applied too rapidly, not allowing sufficient time for proper hardening, or undercoats being mixed heavy with boiled or rosin oil or an excess of japan which did not allow the paint to properly harden and left the under-surface soft and spongy. Such paint is usually tough and elastic and the undercoats are found to be spongy and easily affected by hot or humid weather. This paint usually shows no signs of peeling, as it is very