Brushing on Varnish
Instructions for brushing on and applying wood varnish, varnish application tips and guide, brushing techniques.
¶ The Brushing of Varnish. To one who has not tried it the brushing of varnish, particularly finishing coats which are flowed on rather full, is accomplished merely by dipping the brush into the varnish and spreading it around on the surface, much as wfe spread oil paint. But one attempt to varnish a fairly large surface and get a clean, perfect gloss will suffice to teach anyone that there is considerable skill, understanding and experience yet to be acquired.
¶ The first consideration in the application of varnish is the brush. Needless to say that a perfectly clean, well broken~in varnish brush is essential, quite as essential as good varnish and the proper method of application. No matter whether you prefer a flat varnish brush or an oval, it must be good, clean and well used to do perfect finishing. The fiat varnish brush pictured in Picture 13 is a very common type used for small panels, mouldings, etc., in the smaller sizes, 1 inch to 2½ inches wide. The fiat brushes which are 3, 3½ 4 inches wide are used on floors and other large surfaces. The bristles are double thick and very elastic in order that a pretty good load of varnish can be carried and that thick varnish can be spread and distributed properly. Picture 14 shows the oval varnish brush of common type among furniture and house finishers and to some extent used by automobile finishers. They come in many sizes from No. 1-0 to No. 10-0. No. 2-0 is about 1 7/8 inches in diameter, No. 5-0 is about 2 ¼ inches in diameter and No. 10-0 is 2% inches in diameter. The ovals are very thick and carry a large load of varnish. There is little choice between ovals and flats, except personal preferences;
¶ The successful brushing of varnish merely requires that you work methodically, that you work out a system of brushing which will properly distribute the varnish over the entire surface to an even thickness. That means first, look over the surface to note the best place to begin and to finish so as to take advantage of the natural breaks in the surface, mouldings, edges, joints. carvings, etc.
¶ It is not wise to pour out the last inch or so of varnish in a can because it may contain settlements of grit or crystalized gum or drier. The can should not be shaken unnecessarily and when pouring varnish from it let the stream hit against the side of the pot which has been tilted over a little, this so you will not fill the varnish in the pot with air bubbles which are likely to make your brushing more difficult.
¶ Dip your brush into the varnish deep enough to take a full load, but not so large a load as will drip off the brush. Do not scrape out the varnish on the side of the pot any more than you have to, because that fills the varnish with air bubbles which may make your brushing more difficult when laying-off the coating to finish. A clean wire stretched across the center of the varnish pot is better than wiping on the sides of the pot, if any wiping at all is necessary. It really is better to dip the brush just enough to load it and so require no wiping.
¶ Carry the loaded brush to the surface, the center of a small panel or not too near one end or edge, and with quick strokes moving the length of the wood grain distribute the varnish roughly as far as it will go without too much stretching. Then with the empty brush begin cross-brushing this load, across the grain of the wood. Now the varnish is pretty well distributed, so lay it off to finish by rubbing again with the grain of the wood; using the tip ends of the brush bristles.
¶ Take up your second brush load of varnish and distribute it in the same way, repeating the operation until a fairly large area has been coated in and laid off to finish. Now after the varnish has had a little time to set, the time from the first brushful until the last, you can tell pretty well whether too much has been put on and whether there are going to be any runs, sags or wrinkles. It is well to take your varnish brush when empty, wipe it out more on the pot and with it go over the entire surface to pick up any excess of varnish which may be in evidence in the form of folds, runs or sags near mouldings, corners, etc., brushing with the grain of the wood. Long, light strokes are best for this final brushing, and be very careful not to do this work too late, after the varnish has set so much as to become sticky. Let your brush strokes run up to and over the edges of boards, panels, cabinet tops, etc. Inspect the surface against the light reflections to find any skipped placed, "holidays" as the finishers call them.
¶ The first coat of varnish should always be brushed out thinner than later coats. Put on less varnish and brush it out until a thinner film is distributed than is wanted for the finishing coat. But on any varnish coat it is better to brush it out too thin than to leave it too thick. If too thin it will dry perfectly, as long as you have not skipped any places, and if greater depth of varnish is wanted another coat or two can be put on. But if too thick a coat is spread it is likely to develop such defects as runs, sags and wrinkles which will mar the beauty of the finish. Heavy-bodied varnish should be thinned about 25% with pure turpentine for the first coat only. Then it will sink into the wood cells better, dry harder and more quickly and make a fine foundation, firmly attached, for the future coats.
¶ Allow plenty of time for the first coats of varnish to dry hard. Time cut short on the drying of the undercoats must be added to the drying of succeeding coats and a poorer finish results, too. Each coat of varnish spread stops the drying of the varnish or other coatings under it. On jobs which have as many as four coats of varnish it is well to let the first two coats dry bone hard. The third coat should dry hard enough to rub safely, but not so dry as the first two. Then the last coat will fuse into the varnish body below it and fill up any abrasions where the rubbing might have cut through a little. If the third coat is bone dry and very hard any rubbed through places may show up ia the finish. Of course, it is far better to do the rubbing so carefully that there will be no rubbed through places.
¶ When brushing panels it is well to deposit your first brushful in the center near one end. Then coat-in the corners and across the ends, following up by filling in the centers. That method prevents laying on an excess of varnish on the edges and in the corners, "fatty runners" as they are called. When it comes to laying-off with the final strokes with the grain of the wood, brush the whole panel first with the length of the grain, then across the grain and finally with the grain again. These final, light, long strokes should start in the center of the panel and work both ways toward the ends. They should not start at the ends and finish in the middle as is sometimes done. That method often drags the varnish from the ends and piles it up in the center where it will run, sag and wrinkle.
¶ Finishing coats of varnish are as a rule flowed on a little thicker than the undercoats, but as has been said, if there is any doubt about how thick to flow the varnish, put it on too thin rather than too thick. And when flowing any coat of varnish do not take small brush loads and spread them on small areas. In that way the varnish will set before you can get enough on the surface to cover it and distribute it evenly. Take full loads in your brush, spread it out vigorously and decisively, aiming to get enough varnish on the surface quickly and then you will have more time to distribute it evenly and lay it off to a fine finish. Varnish must not be rubbed-in but applied with a firm stroke.
¶ When varnishing table and cabinet tops or any projecting surfaces be very careful to run your brush up to the edge, but not over the edge. When you scrape the brush over the edge an excess of varnish is left on those places and that excess will run or form a fat edge.
¶ It is well to keep close watch on any varnished surface for a few minutes after the brushing has been completed. Often you can catch up runs, sags and wrinkles with the brush before the final setting and so prevent a disfigured surface. This must, however, be done very deftly to avoid roughing-up the partly dry varnish about the runs.
¶ Buns in varnish after the varnish is dry can sometimes be made less conspicuous in this way,wet a cloth, rub it on a piece of hard soap and then rub the varnish run which is dry and hard. Then take up a bit of pumice stone on the same cloth and gently rub the defective spot. The soap enables you to rub down the excess of varnish without having the pumice stone lodge in the varnish film.
¶ In Picture 15 is pictured the varnish cup with strainer attachment which is commonly used by the automobile finisher. This is a most excellent tool which deserves wider use among other finishers. It permits one to pour out a small amount of varnish at a time, thus preventing the exposure of the large supply. It permits you to strain the varnish often and so remove the grit which the varnish brush is bound to pick up on the surface.
¶ A bit of common cheese cloth, silk or muslin is used each time for straining, is quickly placed between the upper section and the cup and may be thrown away each time the varnish is strained.
Next Page: Applying Varnish by Rubbing.
This is Brushing on Varnish.
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