Repairing Lionel transformer cases made of Bakelite

Last Updated on February 1, 2022 by Dave Farquhar

Bakelite was the world’s first synthetic plastic, invented in 1907 and was commonly used for everyday objects in the mid 20th century. Lionel used it for transformer cases well into the 1960s. As a general rule, if a vintage Lionel transformer case isn’t metal, it’s probably Bakelite. For example, the highly desirable Lionel ZW and KW transformers used Bakelite casing. If you’d like to try to repair Bakelite transformer cases, read on.

Today, Bakelite is a specialty material. Although it’s generally a strong material, there are other plastics that tend to be more durable in everyday use, and they are cheaper. Another problem with Bakelite is that it is difficult to repair, although it’s not impossible.

Years ago there were Bakelite cements available, but they are no longer in production today. About the only way to find it today is to buy it from an estate, which is very hit or miss.

The best modern substitute when the case is broken into pieces is Devcon Plastic Welder. Use it outside and wear gloves for safety. Keep in mind that the stated working time will be shorter on a hot day, and much longer on a cold day. As a general rule, an increase of 10 degrees Celsius doubles the speed of a chemical reaction. So that means in the summer, the times on the package will be about half as long. In the winter, the times will be about four times as long.

Mix up the adhesive on something disposable such as a plastic plate and apply it with a disposable tool, such as a toothpick. If the case is broken into several pieces, don’t try to glue it all at once. Glue two pieces at a time, then bring the pieces indoors and allow the adhesive to cure for 48 hours.

If some of the pieces are missing, leaving voids in the case, that’s a more difficult and costly repair but still possible. Glue the remaining parts back together, then glue some fiberglass cloth to the inside to fill behind the void. Apply some fiberglass hardener to the cloth. After it dries, apply some epoxy putty into the void, sculpting it to match. Once the putty cures, you can file or sand it level with the case if you aren’t able to completely sculpt it to match.

The epoxy putty will be a lighter gray than the Lionel case. But you can paint the putty black afterward for a closer match. The finish still won’t quite match, but it will look better than a void in the case.

If the case has cracks but no breaks, you can flow some ordinary super glue into the crack to shore it up. Squeeze a drop of the super glue to a scrap piece of plastic. Then use a toothpick to apply it to the crack. Capillary action will help the glue to flow into the crack. Work slowly, repeating as necessary. Once the glue has hardened, you can file it to match the surface. You can disguise the repair further by polishing it with Brasso.

If the case is intact but just dirty and dull, here are some tips for cleaning and polishing Bakelite.

The repair will be time consuming, but with some patience, it’s entirely possible to achieve a high quality, lasting repair.

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