Retrotechtacular: Making Porcelain Insulators

Here is a silent film produced by General Electric that depicts the making of many kinds of porcelain insulators for power lines. Skilled craftsmen molded, shaped, and carved these vital components of the electrical grid by hand before glazing and firing them.

Porcelain insulators of this time period were made from china clay, ball clay, flint, and feldspar. In the dry process, ingredients are pulverized and screened to a fine powder and then pressed into molds, often with Play-Doh Fun Factory-type effects. Once molded, they are trimmed by hand to remove fins and flashing. The pieces are then spray-glazed while spinning on a vertical lathe.

Other types of insulators are produced through the wet process. The clay is mixed in a pug mill, which is a forgiving machine that takes scrap material of all shapes, sizes, and moisture levels and squeezes out wet, workable material in a big log. Chunks of log are formed on a pottery wheel or pressed into a mold. Once they are nearly dry, the pieces get their final shape at the hands of a master. They are then glazed and fired in a giant, high-temperature kiln.

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Vintage Kegerator

Vintage Kegerator

[Kerber] got his hands on a classic 1950’s General Electric fridge, and converted it into this classy vintage kegerator.

As his build log shows, it took an intensive restoration process to get this fridge back in shape. He completely stripped it down, scraping off the sixty year old insulation, fibreglass, and glue. Then the chassis was sanded down to a smooth finish and painted black. R-19 insulation was added to replace the old stuff.

Next up was electronics. An Arduino, DS18B20 temperature sensor, and a solid state relay were used to regulate the temperature and prevent frozen beer. There’s also a Guruplug server that reads data from the Arduino every minute. It makes this data accessible through a web page, so the temperature of the kegs can be monitored from anywhere. [Kerber] admits that this is overkill, but leaves room for future expansion.

The kegerator draws about 180 Watts, and runs for about 6 minutes per hour to keep the temperature regulated. This is pretty impressive considering the age of the fridge. The final restoration looks great, and serves up data along with the beer.