Posted By Lee Ainsworth Robert I know of a process we called "WHITE METAL SPINNING", this is used for oil filmed bearings, where metal is heated up and spun mechanically into pre-machined components. If this sounds the same as you are looking for, I may be able to get some info for you. Let me know. Lee

Posted By Jane Blunt Dear Robert The process you describe goes under several names. 'Flame spraying' and 'Thermal Spraying' are two others. The consumable may be in the form of a powder, wire or cord, and you do not say which. There are two other points that are important - is this the hand held, low velocity version, or the high velocity version? The latter would normally be mechanised and carried out in a dedicated booth with integral fume extraction. The former would not, because the operator is holding the gun in his hand. What follows assumes that it is the hand-held version. The health effects of aluminium are: long term inhalation of aluminium powder or aluminium oxide may cause scarring of the lungs, Aluminium powder is highly flammable, and can form explosive mixtures with air. It reacts with water to form hydrogen. Zinc: zinc can cause metal fume fever, but is otherwise only moderately toxic. The dust is highly flammable, pyrophoric, and can form explosive mixtures with air. It reacts with water to form hydrogen. Thermal spraying relies on the formation of fine droplets of metal to be propelled to the surface and stick there my mechanical contact. Not all of the spray will reach the target, and not all of it will stick, so there is an appreciable amount of metal fume released into the atmosphere. Extraction of the fume is important, even when working on site. Full PPE would also be appropriate, since this process is not mechanised, and the operator is close up. Most thermal spray processes are noisy, and there are associated hazards such as grit blasting to prepare the surface, and disposal of dust from filters, etc. If you collect zinc dust, for instance, you can face the problem of the dust collector going up in flames (seen it!!). There is a Trade Association, The Thermal Spray and Surface Engineering Association, website http://www.tssea.co.uk/ . They have an industry code of practice, written in cooperation with the HSE, which is slightly biassed towards the mechanised processes, but you may nevertheless find useful. It covers flame spraying, plasma spraying, high velocity oxy-fuel spraying and arc spraying. One of the worked examples is a site operation to spray zinc, so is relevant. Regards Jane