Q. We are in the process of remodeling the old paint line in our plant. I am an industrial engineer responsible for investigating modern painting and curing methods and designing the new facility. What are the pros and cons for using gas or electric to heat a typical automotive supplier curing oven? I’m familiar with gas convection ovens, but have never used electric fired ovens. This would be used for curing exterior painted plastic components. R.H.
A. Simply stated, heat is heat. In essence, the paint doesn’t care if the heat comes from an electrical resistance heated oven, or from gas, coal or even wood-fired ovens. The big difference will be in the cost of operation. This is especially true if you are considering indirect fired ovens in which the flames are contained in a heat box and the oven air is heated while passing over a heat exchanger.
On the one hand, in indirect gas fired ovens, the flames and products of combustion are contained in the heat box. With that in mind, electrically heated ovens using resistance heating would behave in the same manner. On the other hand, in direct fired ovens, the flames heating the oven air are in the curing chamber along with the products of combustion which could cause appearance problems on the coating’s surface.
However, if when you said electric ovens, you were referring to electric infrared (IR) ovens where painted parts are heated by radiation and the air is heated slightly, there could be gains in efficiency owing to fast heat-up rates. There are also black surface gas-fired infrared ovens. Infrared ovens are particularly suited for curing powder coatings, because there is little air movement around the coated parts. This minimizes disturbance of the uncured powder particles. IR ovens are frequently used to cure liquid coatings