Reclaiming the Screen
After the screens are cleaned of all the plastisol and other debris, the emulsion must be removed. Emulsion is nothing more than photosensitive glue and can be very stubborn at this point. Emulsion removal is accomplished by washing the screen with a mild acid. After brushing both sides of the screen, the acid should be left to work on the emulsion for a period of no more than 5 minutes. Special care should be taken to rinse the emulsion remover within a short period of time and not allowed to dry.
If the emulsion remover dries on the screen it tends to act as a bonding agent which makes the cleaning process more difficult. Clean-out is best accomplished with a pressure washer. We use one that is rated at 2300 psi. The emulsion usually washes out easily at this point. Once the screens are dried a good soap is used to neutralize the screen. There are many good specialty soaps on the market for this purpose. The screen must be completely dried out before it can be returned to the storage rack where it can be used once again. It is a good idea to store the clean screens where they will not accumulate dust or dirt.
Coating a clean screen with emulsion
Some emulsions used to coat the screen are made of glue and photo sensitive chemicals in liquid form. There are many different type of emulsions on the market; some require the end user to mix the glue and photo sensitive chemicals, while others come premixed. It took us nearly four years of constant trial and error before we found the one we liked and continue to use today. The price of the emulsions can range anywhere
from $20.00 to $75.00 per gallon. The cost is all relative compared to the amount of screens that can be coated with that one gallon. The emulsion is poured into a trough like dispenser that is used to coat both sides of the screen. There are many formulas for coating. Some people coat one time on one side and three on the other. We like to put two coats on both sides of the screen.
Once a screen is coated it must be placed in the rack to dry. A dehumidifier that does not blow much air around the drying rack is suggested and helps speed up the drying process. With a dehumidifier and a high quality emulsion, we expect our screens to be ready for re-exposure for the next image within one to two hours. Without knowledge of all the gimmicks a screen may take up to twelve hours to dry.
Talk with you soon!
Prince Denny