When the paint is cracked in small hair lines, it is usually called crazing of the paint. Generally these hair lines run crosswise of the grain the entire width of the boards to which the paint is applied. The paint is invariably very hard and this crazing is often attributed to an excess of zinc. It is usually caused from an improper reduction or combination of pigments which do not dry uniformly, one being more easily affected by heat old than the others, thereby leaving a paint surface which is not uniform as to contraction and expansion. This trouble is especially noticeable on parts of work that have to withstand a great deal of vibration. If the paint has not 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 not 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 tough and seems to be firmly adhering to the wood, but to repaint the surface requires a great deal of care in keeping the new paint from following the first coats and cracking in like manner. Be careful not to have an excess of paint on the surface, as such will blister and peel.

Thoroughly clean the surface with a wire brush. Mix the first coat of paint fairly elastic or with 1 pint to l 1/2 pints of turpentine to a gallon of paint. This will not dry too hard and will be sufficiently elastic to withstand contraction and expansion over this treacherous surface, also penetrate to a good depth. Brush out well and do not attempt to fill the cracks with this coat. The finishing coat should be mixed to a good consistency with 1-32 to 1-16 gallon of turpentine to the gallon of paint and be well brushed over the surface. If, however, all of the old paint is solid and dried through, a half-elastic coat, 1/4 gallon of turpentine to a gallon of paint, can be applied and should be well brushed into the cracks. This will dry firm and hard and a second coat of elastic paint can be applied over it. This, well brushed into the cracks, will to a certain extent fill them and make a very passable job without danger of blistering, which would be the result if a first coat of very elastic paint had been applied.