SPRAY PAINTING.

Press, Volume LXIX, Issue 20919, 28 July 1933, Page 7

SPRAY PAINTING.

RUNNING WATER TO CARRY OFF FIJ.MKS. Probably the majority of motorists know that paint-brushes are conspicuous by their absence in the departments of motor factories where cars are given their numerous coatings of cellulose "paint." The cellulose lacquer—to use the more generally accepted term—is applied by means of air pressure. But drawbacks of spraying from the factory point of view are, first, that the spraying booth must be ventilated in a special manner, to carry off the fumes which arise fjom the spray, and which are distinctly harmful to the health of the operator; and the fresh air, too, must be filtered before it is allowed to enter the spraying booth to clear it of the slightest suspicion of dust. The second drawback is that a certain proportion of the lacquer is wasted, for while most of it after issuing from the "gun" adheres to the surfaces of the car under treatment, some of it, in the form of an almost invisible mist, fiies off, and eventually settles on the floor. It is of interest to learn, -therefore, that at the overhauling depot of the London General Omnibus Company a new scheme has been devised whereby both of those drawbacks are largely avoided. The spray-painting is done over running water. The scheme is based upon the well-known fact that water in a room that is being painted tends, for some reason, to attract the fumes that cause an objectionable odour So the vehicle or body to be sprayed stands in a shallow bath of running water, which is warmed in cold weather. The water appears to collect all superfluous paint, and does this so effectually that there is no need for the operators to wear masks, as is the case where ventilation is sluggish; nor is there need for an exhauster fan to draw off fumes. The waste of lacquer is avoided by collecting the running water in a central gully and carrying it to a separator, where the lacquer floating in the water is recovered for further use at practically no cost, except the small capital charges attached to installing the apparatus.