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Catalin vs Bakelite


Strictly speaking, Catalin and Bakelite are both tradenames for the same compound: phenol formaldehyde. However, the terms are often used to distinguish cast phenolics (Catalin) and molded phenolics (Bakelite). Which terms are used largely depends on the circle in which you run. Radio collectors refer to the brightly-colored cast phenolics as catalin, despite the cast radio parts being manufactured by Bakelite, Catalin, Marblette, Monsanto, and Knoedler. Vintage Mah jong collectors refer to opaque game pieces as bakelite and more translucent or swirled pieces as catalin. Jewelry collectors refer to all phenolics as bakelite. Below, to avoid confusion, I capitalize the company name and leave the generic referral uncapitalized.

In "Plastics History U.S.A.", a comprehensive history of the plastics industry between 1890 and 1950 by J. Harry DuBois, Catalin receives little more than a footnote, despite a great deal of detail of the processes used to manufacture the phenolics, and the people involved in their development. After reading this book, I get the distinct impression that the term "catalin"probably receives more use than it merits.

In order to produce the molded phenolics, phenol and formaldehyde were mixed and heated with an alkali catalyst. The resulting resin was cooled, powdered, and mixed with a filler such as wood flour, powdered walnut shells, or asbestos. That mixture was then placed into a heated, pressurized mold which produced the final product – telephone receivers, electrical parts, camera cases. The original resin was amber-colored, and therefore this was best suited for darker plastics.

Bakelite Corporation was making a cast phenolic long before its patent ran out in 1927. A special interest of one of the company's chief chemists was this transparent colored form, from which Bakelite made pipe stems, billiard balls, and jewelry. When the patent for bakelite ran out in 1927, the Catalin corporation, among others, began making their own cast phenol formaldehyde plastic. To make a cast phenolic the initial resin was kept liquid, dyed the desired color, and poured into molds to harden with heat and hydrostatic pressure. By mixing different batches together, they could produce pieces with swirled or marbled patterns. The lighter color of this resin allowed it to be more brightly-colored and translucent.

Molded phenolics, by virtue of their filler material, are opaque, stable and very tough. They are resistant to chips and cracking. Cast phenolics are colorful, weaker, and over time can warp and crack. See more under Identification of Plastics. I have looked at many Mah Jong tiles, and they do give me pause. Some are obviously translucent, swirled cast phenolic. But the rest are variably opaque, and if you sand them down are light ivory inside. Most have had their designs pressed into the surface of the plastic. The light interior suggests casting, the pressed design and opacity suggext molding. If anyone knows the method of their manufacture, contact me. I'd love to know.

When it gets down to brass tacks, it seems no less accurate to call all phenolics bakelite than to make a distinction based on color or translucency. If I wanted to be strictly accurate, I would call everything either "cast phenol formaldehyde" or "molded phenol formaldehyde". But I would get carpal tunnel sydrome from all the typing, and frankly I don't feel the need to be that precise. Through the rest of the website I call most phenolics "bakelite", but throw in "catalin" from time to time just to be difficult.

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