Room Decor Inspiration
COATING KNOTS IN NEW WOOD WITH “KNOTTING” BEFORE PAINTING.
If a small brush is not available, knotting can be applied with a bunch of rag or sponge properties of the ready-for-use primers are approximately 40 square yards per 14 pounds and 100 square yards per gallon respectively.
Primers have very little weather resistance, and must be subsequently coated with finishing paints. Primer is only necessary on bare surfaces; for repaint work, undercoat can be applied over the old finish when same has been properly prepared. Primers require from twenty-four to thirty-six hours to dry.
The object of an undercoat paint is to build up film thickness and provide an obliterative coating. For this reason extra pigment is incorporated in paints made specially as undercoats, special undercoats are not necessary in all cases, and two or lore coats of the finishing paint when properly adjusted rre satisfactory. A rule on the matter of paint undercoats is lat when gloss paints or enamels are to be used for the nishing coat, a special undercoat is required; it is also jcommended when dark-coloured surfaces are to be painted ith light shades.
Due to the relatively large proportion of pigment in under-sat paints, and the fact that pigments are chosen primarily r r their obliteration rather than protective properties, undercoat paints have little or no weather-resisting qualities.
Undercoats dry with a matt or dull finish, and should thinning be necessary use only pure turpentine; on no account add linseed oil unless recommended by the manufacturer, as this would cause the paint to dry with a gloss and the film would be softer than it should be, and may cause the finishing coats to crack or shrivel. The covering capacity of undercoats varies considerably, but on an average 1 gallon covers 80 square yards.