Stripping, plane and simple

A new system for dry stripping paint work using plastic media is discussed. Plastic media blasting (PMB) is similar in some ways to conventional blast cleaning, more technically known as the impact treatment process. Plastic granules are introduced into a pressure air stream and ejected at considerable speed from a nozzle. The stream of particles is directed at the surface to be stripped. Where the systems differ is that with PMB the air blast pressure is usually much less than that used for conventional blast systems, maybe less than 20 psig, and the technique is different in that the angle of attack is very shallow, 15° to 30° to the surface rather than around 90°. The system uses a feeder, called the Precifeed, which has a conveyor belt four inches wide. The rear roller is barrel shaped, while the front roller is concave in profile. They are around 12 inches apart. In the middle of the belt, at the back of the feed tube, is the puddle roller, a doughnut shaped wheel, which creates a depression or 'puddle' in the belt. There are also a couple of small rollers on either side of the belt to help maintain the shape of the 'puddle'.