Gas and electric dryers offer different advantages for screen printers depending on budget, required capacity, available floor space, and the cost of gas versus electricity.
Gas dryers have an open flame that heats the air within a chamber and transfers the heated air to the area the garments pass through. The heat is then transferred to the ink by air convection. This is the equivalent of heating food slowly in a gas oven. By contrast, an electric dryer uses infrared radiation that causes the ink molecules to vibrate, generating heat that quickly raises the temperature of the ink without heating the air around it, similar to heating food in a microwave.
The primary advantage of a gas dryer is its ability to maintain a constant temperature and avoid overheating the ink. Primary disadvantages are longer dwell times and long dryer lengths that can increase cost and consume floor space. Additionally, thick insulation is needed to prevent the outer walls from attaining dangerous temperatures. As a result, gas dryers are generally recommended for large print shops, providing that natural gas or propane is available and less expensive than electric locally.
By comparison, infrared dryers are small and less expensive because they do not require insulation and are shorter in length due to the reduced dwell times. Infrared radiation attains ink curing temperatures more rapidly and efficiently than heated air, particularly when curing plastisol inks. However, if items are conveyed through an infrared dryer too slowly, the ink can overheat and break down chemically.