Wood Finish from old Records

Next time you’re working on a project that needs a durable wood finish, don’t grab the polyurethane. Follow [Victor Ola’s] advice and raid your grandparent’s record cabinet for some old 78 records. Modern records are made from vinyl. The stiff, brittle old 78’s from the 1960’s and earlier were made from shellac. Shellac is a natural material secreted by the female lac bug. It can be thought of as a natural form of plastic and was used as such for years until man-made plastics became commodity items.

Older 78 RPM phonograph albums are usually made entirely from shellac. [Victor] started by taking a few old cracked records and pulverizing them with a hammer. The shellac crumbs were then poured into a mason jar along with some isopropyl alcohol. The alcohol dissolves the shellac, creating a thick goo. More alcohol will thin the slurry down to a paintable consistency. The mixture is then ready to be painted on any wood surface. Wiping off the excess will reveal the wood grain.

Shellac is normally amber in color. Records are black because carbon is added to the mix. This makes the shellac stain dark and makes it a flat finish. While it would be fine to leave it this way, [Victor] added a coat of lacquer over his shellac stain to achieve a glossy finish on his upcycled gramophone.

If you’re getting into woodworking, don’t worry – anyone can do it. Just make sure you have sharp tools.

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Retrotechtacular: Wax On, Wax Off: How Records Are Made

In this 1942 tour of the RCA Victor plant in Camden, NJ, we see the complete record making process from the master cut production to the shipping of multiple 78RPM shellac pressings. The film centers around a recording of Strauss’ Blue Danube waltz as performed by the 1940s equivalent of studio musicians, the Victor Salon Orchestra.

The master record starts life as a thin layer of molten wax poured on to a hot circular plate in a dust-free room.  Bubbles and impurities are blow torched out, and the wax is left to cool under a steel dome. This perfect disc is carefully passed to the recording studio through a special slot, where it is laid carefully beneath the cutting stylus.

Unlike today’s multi-track recording sessions, the master was cut from the performance of a complete band or orchestra all playing as they would in concert. The sound engineer was responsible for making fast changes on the fly to ensure sonic  and groove width consistency. 

After cutting, the delicate wax undergoes several phases of electrolysis that form the metal master. It is bombarded first with pure gold and then twice with copper sulfate to build a sturdy disc. The copper ionization process also ensures high fidelity in the final product.

Although mighty, this master won’t last long enough to make all the necessary pressings, so a mother matrix is made. This is a negative image of the master. The mother is formed by electrolytically bathing the master in nickel, and then adding a thin film of some indeterminate substance. Another copper bath, and mother emerges. As soon as possible, the master is separated and whisked away to the storage vault.

Since a positive image is needed for pressing, a stamping matrix is made. Mother gets a nickel bath for durability, and then a copper bath to form the stamping matrix. Many stampers are created so that several records can be pressed at once. These images get a chromium plating to help them last through many pressings.

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