Varnishes

Varnish has long been considered the best finish for fine furniture by furniture finishers. Because it was always slow in drying and required careful application by brush, it never was popular with furniture manufacturers.

Natural Varnishes The natural varnishes used for many years were a combination of oil and natural resin, and the different names you may have heard — spar varnish, bartop varnish, church pew varnish, gymnasium varnish, piano varnish — really were references to the percentage of oil used in the formulation. The more oil in the mixture, the more durable and flexible it was. But an increase in oil also increased the drying time.

Thus, varnishes intended for tough use, such as spar and bartop mixtures, had more oil and had to be given long drying periods. Varnishes that needed to be hard or intended for a beautiful hand-rubbed finish were made with less oii. They dried quicker and harder, but were more brittle and scratched easily.

Synthetic Varnishes Then paint chemists discovered how to incorporate manmade resins into varnish formulations, and everything changed. Manufacturers were able to control hardness, flexibility, drying times and so on, to produce formulations that would satisfy the special needs of the spar maker, the piano maker, the furniture maker and the church pew maker. You can still find natural varnishes in specialty stores if you are intent on duplicating the finish of an old and valued piece, but the great majority of available varnishes are made with man-made resins, and generally are referred to as synthetic varnishes. There are four basic synthetic vamish formulations: alkyd, phenolic, urethane, and plastic.

Alkyd varnish The alkyds arc available in glossy and satin (matte) finishes. This formulation is excellent for producing good hand-rubbed finishes. The varnish tends to be somewhat yellow in color and darkens any wood to which it is applied. Nor does it brush on as easily as a urethane finish. You will find some formulations that combine alkyd and vinyl, to produce increased flexibility. Drying time is relatively slow and varies from maker to maker.

Phenolic varnish Usually available only in glossy finishes, the phenolics have

Many people don't take the time lo do it. but we have found thai applying a limsh to all surfaces ol a drawer, inside and out, makes sense. It seals the drawer againsi moisture and cuts down on swelling and cracking

the reputation for being tough and weather resistant. For this reason, they are extensively used in exterior applications around the home and on boats. Phenolic varnishes are quite yellow when applied, tend to darken wood, and they get yellower as they age on the wood. This means that you must start with a lighter stain to achieve the color you want, and you should be prepared lor further darkening over the years. Drying time is on the slow side.

Urethane varnish The urethane combinations are probably the best for furniture work. They are the easiest to brush on, and faster drying than either the alkyds or the phenolics. They arc the clearest (least yellow) of the varnishes and don't darken after application. They do. however, darken the wood to which they are applied, so be sure to color-test them over the stain you arc using. They rub out to a handsome finish, and are available in gloss, semi-gloss, satin and flat. You can find spraying versions of urethane varnishes if you intend to spray instead of brushing the finish on. Drying times vary considerably with the brand, so check the label and follow application instructions carefully.

In our opinion, the urethane varnishes are the best for furniture finishing. They are easy to apply, rub out nicely for a beautiful final finish, resist water, alcohol and general wear, and look good. You can achieve either a deep gloss finish or a satin finish without difficulty.

Vinyl varnish Most furniture people won't call a vinyl finish a varnish. Instead, they refer to it as a plastic finish. The vinyls certainly have totally different characteristics than the three varnishes already mentioned. For one thing, they dry in 15 minutes. They are absolutely clear and don't change color after application. They have good resistance to water and alcohol, but they suffer from abrasion so you don't hand rub them at the end of the finishing process. Vinyls can be brushed on or sprayed on, come in gloss and semi-gloss, and generally are thought of as fine finishes for wall paneling.

The old varnish had a glossy surface As a result, we had to sand both sides of the tray to break the gloss so that there would be enough tooth for a new coat to catch hold.

Next, we appl ed a coat of varnish to the damaged area. When this dried, the entire tray was varnished to fully restore the tray.

We tried finish remover on the bad spot but it didn't work. The finish appears to be a heavy coating of polyurethane varnish Ouroniy choice now is to sand out the bad spot as far as necessary to remove any discolored wood. Fortunately, not much sanding was required, so the surface ol the wood remains unharmed

The first step is to test the finish, using first denatured alcohol, then lacquer thinner, to find out what type of finish was jsed Neither of these chemicals affected this so we believe the tray probably is varnished

This is a solid mahogany tray that someone has lefl a very hot. wet pot on Our job is to attempt to restore the surface.

We tried finish remover on the bad spot but it didn't work. The finish appears to be a heavy coating of polyurethane varnish Ouroniy choice now is to sand out the bad spot as far as necessary to remove any discolored wood. Fortunately, not much sanding was required, so the surface ol the wood remains unharmed

The old varnish had a glossy surface As a result, we had to sand both sides of the tray to break the gloss so that there would be enough tooth for a new coat to catch hold.

HOW TO APPLY The first rule in ap-A VARNISH plying any modern

FINISH varnish is: Read the label first! The second rule is: No matter what we tell you here, follow the instruct lions on the label.

The reason for these rules is every formulation today is different in some degree from its neighbor 011 the shelf. Since no two are exactly alike, every varnish can require special rules of application. We can only give you generalized instructions. The manufacturer is extremely interested in helping you obtain good results with his product, so his instructions generally are the best.

Wood Working for Amateur Craftsman

Wood Working for Amateur Craftsman

THIS book is one of the series of Handbooks on industrial subjects being published by the Popular Mechanics Company. Like Popular Mechanics Magazine, and like the other books in this series, it is written so you can understand it. The purpose of Popular Mechanics Handbooks is to supply a growing demand for high-class, up-to-date and accurate text-books, suitable for home study as well as for class use, on all mechanical subjects. The textand illustrations, in each instance, have been prepared expressly for this series by well known experts, and revised by the editor of Popular Mechanics.

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