Small pieces and thin gauge metals can be easily cured with special lamps. The operator has to closely monitor the light distance and the temperature to prevent the powder coat from burning out or discoloring. In some cases, the operator will be necessitated to position the light closer to the surfaces to acquire high temperature and speed the curing process. The key to successful curing is constant supervision of the temperature. It is quite easy to monitor temperature with hand-held equipment.
When using hand-held equipment, you will note that the temperature can rise beyond the specified point in less than five minutes. When the temperatures exceed the limit, you pull back the light a few inches from the surface to maintain the recommended temperature.
Temperature requirements: Infrared cure lamps are used with infrared thermometers to obtain precise temperatures. The lamps have an adjustable stand which gives you the power to shift the light around the item for complete curing. Different colors and powders have different temperature requirements. For instance, if the coater uses specialty or translucent powders, he/she must operate with a minimum of 3650 F and a maximum of 4000 F for 25 minutes. When working with clears and solid colors, you should operate with a temperature range of 3200 F and 4000 F for 15 minutes. Curing at higher temperatures is acceptable on condition that you maintain the specified time.
The difference in time and temperatures are dictated by the chemical composition of the powders. The curing lamps come with a chart that specifies the temperature for various powders. To get quality output, it is recommended that you use the average cure temperature indicated on the chart. If the temperatures exceed 4000 F, the powder is at risk of getting burned, particularly for light items such as sheets that get heated up quickly. Additionally, some colors for example solid white and reds are prone to get burned at extreme temperatures.
New users should use the recommended temperatures. However, as they familiarize with the infrared lamps, they can increase the range of temperatures to hasten the curing process. Most of the powders can resist to over bake provided the temperatures do not exceed 4000 F.
Distance specifications: Before the powder is applied, the lamp should be positioned 4 inches from the surface. If the temperatures exceed 4000 F, move the equipment away by one to two inches. Closely monitor the light distance especially for light materials that get heated up quickly. Due to good heat absorption qualities, heavier materials get heated up slowly and retain constant temperatures. Though the temperatures will be much stable, you will still be required to monitor regularly.
To get a fine coating, cure from the bottom up and then top-down until you get the desired output. For small pieces, cure from one end to the other and back to the other side. Once your surface has obtained the recommended temperatures, set the timer and monitor the conditions until the piece is cured. Remove the powder coating lamp and let the piece cool down.
Testing the cure: After the curing process, test if the cure was complete by rubbing the surface with a soft rag. If the color is easily transferred to the rag, the cure is incomplete. Ensure you use the chart well to get a complete cure.