Before going on to the subject of priming, it will be convenient here to deal with the application of paint in general.
The first essential is that the paint should be of the correct consistency for brushing. This must depend not only on the porosity of the surface to which it is to be applied, but also on the nature of the paint itself, for it will be found that various types of paint require different amounts of adjustment to bring them into the condition most suitable for use. White-lead paints, for instance, need to be thinned rather more generously than do those based on zinc oxide which brush out freely when in a fairly stiff, or ‘ round,’ condition; again, graphite paints, owing to the structure of the pigment, possess a natural ‘ slide ‘ which enables them, after only a minimum of thinning, to be brushed out to an even and thin film with comparatively little effort.
All that need be said on this point, therefore, is that a good and properly mixed paint should work well under the brush, with just a suggestion of’ pull,’ but not too much; there should be no tendency for it to pile up or to show deep brush marks, and though it should flow freely and easily, it should always be under control. It takes experience to know by the feel when a material is of exactly the right brushing consistency, but it is obviously important that it should be in this condition since, if it is not, he appearance of the work will suffer.
White-lead paint should always be applied as sparingly as possible and be thoroughly well brushed out. The skilled craftsman uses paint as if it were very precious and as though there were very little to complete the job.
The brush should not be dipped too deeply into the paint and the bristles should be pressed gently against the edge of the container to distribute the paint evenly. It should be applied to the surface in long, rhythmical strokes, backwards and forwards, an even pressure being maintained. The paint should be put on at short intervals on the surface and then crossed, the brush being drawn in a direction at right angles to that originally taken, in order to spread the material as far as it will go. These two operations should then be repeated, and finally the paint laid off lightly to eliminate brush marks as far as possible.
Importance of Stirring
In some types of paint, the pigment portion tends to settle at the bottom of the can more than in others, and if complete amalgamation with the vehicle is not effected, the paint will be far too thin and lack hiding power at first, gradually becoming far too thick for use. Yet it is not uncommon to see a painter take a piece of stick – which may or may not be clean – dip it about half-way down the container and rotate it half-heartedly for a few minutes, barely touching the solid mass of pigment at the bottom. Another not infrequent mistake is to stir round and round the outer edge, boring a channel in the sediment of pigment, but leaving the centre of it unaffected.
Mixing should always be carried out with a broad paddle, and it is worth while investing in a set of these, of varying sizes to use according to the dimensions of the container, and preferably made of iron so that, after use, they may be easily cleaned by being held over a flame. The process of mixing should be a beating and lifting operation in order to ensure that the paint is of the same consistency all through. With paints in which the pigment is liable to settle comparatively rapidly, stirring should take place at frequent intervals during application.