Q. An impressive pair of church front doors facing west are under a deep portico and thus protected from direct weather. However, they are in bad shape, albeit professionally weatherproofed several times in the last 10 years with varnish and polyurethane. The sun beats on the doors on summer afternoons. I would like to sand the doors and treat them on a periodic basis with a mixture of one-third boiled linseed oil and two-thirds turpentine. Is this proposed treatment detrimental? David W. Allen Washington, D.C.
A. Our faithful consultant, William Fite of Frazee Paint Company, San Diego, Calif., writes: "I suggest that rather than sanding down the old finish, use a paint remover to thoroughly remove the old finishes.
"As far as using a mixture of boiled linseed oil and turpentine, there is no reason why this could not be effective. However, as with any front-door finish which is exposed to the sun, a regular maintenance program, say every six months to a year, will help the doors stand up better.
"Consider applying two or three coats of varnish on the side, bottom, and top edges of the doors. These are the areas most susceptible to moisture penetration.
"If these areas are sealed properly, the problem of moisture getting into the wood and swelling it is greatly reduced."
Architectural specifications as to painting of new doors require an equal number of coats of finish material on the side, top, and bottom edges as on the faces. When painters fail to cover the edges, door paint problems often follow.
Manufacturers' new-door guarantees are contingent on the same number of coats on the faces and edges as well as the use of the same paint on the inside and outside faces.
Aesthetics sometimes calls for one kind of paint outside and another inside, but this differential may cancel a new-door guarantee if trouble ensues.