Thermal Spray Gun Maintenance

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The lifeline of your thermal spray coatings facility is needless to say the capital investment in thermal spray coating equipment. It is unbelievable but is true how many thermal spray shop owners pay so little attention to the proper maintenance and care of their thermal spray guns. Many of them operate on a breakdown maintenance schedule where they believe in “If it aint broke, don’t fix it” – that attitude inherently has the hidden implication that “if you try to fix it, you may break it even more”, meaning they have no faith in their thermal spray maintenance personnel or that “if you try to look too hard, you may find other problems that I don’t want to know about ”. In either case, poorly maintained thermal spray guns will end up producing bad coating quality leading to more re-work and unwanted expenditure and in extreme cases can even lead to accidents and injuries. Every thermal spray shop including the very small mom and pop operations must have a thermal spray gun maintenance program in place that they follow meticulously. Developing a written procedure not only documents what needs to be done, but gives an insight into what all could be improved in order to keep thermal spray equipment in good working order so you could have repeatability in thermal spray coating quality. In this article we are dealing only with thermal spray guns. Just changing the nozzles and electrodes when they wear out beyond recognition is no maintenance. Develop a habit ( and a procedure ) to take the gun apart and rebuild it completely, inspecting and replacing parts as necessary every eight hours of operation. If you run the thermal spray booth only two hours a day, ( may be you should replace the salesman and find one that will get more work ), then you can run for four days and then perform gun maintenance; on the other hand if you run your thermal spray booth sixteen hours non-stop, ( make sure your salesman does not quit ), then stop the operation at the end of eight hours and perform a gun change and send the first gun to be re-built. Ensure that nozzles, electrodes, o-rings and seals have been thoroughly inspected and properly re-built. If your maintenance personnel are not very confident, several of the oem equipment manufacturers have classes that they conduct in this regard and it might prove very useful to send your maintenance people to attend these courses. Another key point to note is using replacement components that are not from the oem. I personally do not vouch for non-oem components to be used in your thermal spray systems; sure the look-alike copy from John Doe down the street may look like the genuine original manufacturer’s piece, but what about the chemistry – does the product contain levels of lead beyond acceptability standards – do you know or are you given proper certifications? You know in addition to producing good thermal spray coatings, you are also dealing with liability issues in case there is an accident involving a thermal spray guns in your shop – is the risk worth the saving in using non-oem nozzles and other components? You have to be the judge. In all cases, thermal spray gun maintenance procedures should become an integral part of your operations.