We manufacture custom electronic enclosures. We recently installed a powder booth due to our customers' requirements for powder coat finishes. The problem that we are facing is that our customers do not want to see fasteners after painting. We have not been able to find a suitable putty or filler to hide pressed-in fasteners, countersunk rivets, etc. It seems that the available fillers are not rated for the temperatures required for curing the powder coating. We have resorted to painting, sanding, and repainting until the fasteners disappear. Are there products available for this process, or what would you suggest we do to hide the fasteners? J.D.
There are two things you can try. First, try using textured powder coating formulations. These coatings are designed to hide metal defects and are available from most powder coating suppliers. Their applied coating thickness is 3-5 mils, normally enough to hide most surface defects like scratches and rivet heads.
There are only two fillers that I know will work under powder coatings. One is called Lab-Metal (available from Alvin Products); the other is called Durabond (available from Dura-Chem). Their contact information is available through the supplier directory on www.pfonline.com. Both of these fillers will withstand the heat required to cure your powder coating. Both can be sanded to provide a smooth finish, but only Lab-Metal is conductive for powder coating large areas. However, if the filled areas are just large enough to hide the fasteners, you should not have a problem using either of these fillers.