Providing high quality and expert powder coating services across the Midlands and beyond.

Inclusions; Small particles of dust or residues that are visible on the surface of the part. This will be caused by poor preparation of the part prior to coating. Components should be wiped with a clean lint free rag and then just before they are coated blown off with a stream of compressed air. N.B. sometimes around welded areas there is welding splatter that can be mistaken for inclusions. The way to determine this is to scratch them with a screwdriver and see if they dislodge, if they do then they are inclusions, if they will not then it is welding splatter and feedback should be provided to the Welders. There are various solutions available that can be sprayed onto an area to be welded that lessen the effect of welding splatter.

Uneven Coating; This is a Sprayer and/or Gun set up problem. The process of applying an even coat all over a part depends very much on the concentration of the sprayer applying the powder. It is important firstly to have the gun set up correctly so it is discharging powder that is sufficiently dispersed that it can be applied evenly, if too much powder is arriving at the tip of the gun and there is not enough purging air to disperse it into an even cloud then you will get what are called ‘surges’. These result in a build up of powder in one particular area where the gun has effectively ‘spat’ an uneven unbalanced amount of powder out of the tip of the gun tip causing an unsightly build up of powder in one area. This also results in more powder being used and affects the profit/costs of a job.

Also where intricate parts are being coated the sprayer must move the gun in a continuous motion ensuring that the gun does not dwell in a particular area for any reason. If it dwells it is applying a greater amount of powder to an area that will result in an ‘Orange Peel Effect’ which can look unsightly especially when compared to other areas that have a smooth even coat applied.

Areas not coated; when spraying intricate parts it is easy to miss particular area, this is not so apparent when spraying the part in the booth as the area will have some powder applied but not enough to fully flow and cover the component. This again is a sprayer issue, the key word here is ‘repeatability’, the Sprayer should learn the movements and timings needed to spray a part evenly all over and concentrate so that each part is sprayed by repeating the actions of the one before, the same movements, the same amount of powder applied to all of the areas necessary.

Masking not applied accurately; This occurs when the masking is not to the correct specification. It pays in these cases to have a drawing of the component with the areas where powder is not required highlighted so that the person in charge of masking knows exactly where the masking is to be applied and can refer to the drawing if in any doubt.

Under curing of parts; It is not easy to spot under curing and it can easily be missed. The first sign is that the coating looks very glossy. If powder coating is cured correctly it may be glossy but will have a slight ‘bloom’ to it so that it is not un-naturally glossy. Also look for parts of the component that are made of a heavier material, are they more glossy than other thinner parts. A rather crude way is to take a component and hit it sharply with a hammer, perhaps in an area of the part that is not important, if the powder coated surface chips or come away from the substrate then you know that it is under-cured.