There are many uses for an electric oven of the industrial type in small shop and laboratories, where moderate baking temperatures, accurately controlled, are necessary.
Small parts, which have been painted or lacquered often require baking. Damp or wet pieces of equipment may require drying out. Windings, after dipping in insulating varnish, need a certain amount of baking. Then too, an oven may be required in laboratory work of a special nature.
The oven illustrated was built in an electrical engineering laboratory and has proven invaluable.
Measuring 24x18x16 in., this oven is small enough to be used on the bench, yet it will accommodate quite a bit of work. Heat is provided by two 350 watt strip heaters, which are mounted to the inside surface of the oven, at each side and quite near the bottom. Control is provided by a Fenwal Thermoswitch, which is mounted on the end of the oven. This device has a brass 140 tube projecting into the oven space in which thermal contracts are built. With an arrangement of a dial and knob, as shown, it is possible to accurately control a range of settings to 400 degrees Fahrenheit.
The material used for the sides, top and bottom of the oven is ¼ in. asbestos-cement board, known as Transite. Angle iron is used as a framework and the cover is equipped with strap hinges and a wire pull handle. This insulating and heat resisting material is adequate with moderate temperatures of 140 to 150 degrees Fahrenheit. But at higher temperatures there will be too much heat loss through the material and added insulation will be necessary. A temperature of 200 degrees Fahrenheit is about the limit that can be obtained with the wattage mentioned and the insulating material shown.