Coating Interior Surfaces
We have a requirement to apply a liquid dry lubricant product to the inside of an aluminum gun part that is one-inch ID. Our problem is to find a spray tip or system that will work in this confining space and not result in a course finish. We have the mechanism to advance an extension into the part, but can’t find a tip that will perform.
Q. We have a requirement to apply a liquid dry lubricant product to the inside of an aluminum gun part that is one-inch ID. This coating is a dark gray moly-lube and more difficult to apply than lacquer. Our problem is to find a spray tip or system that will work in this confining space and not result in a course finish. One spray gun supplier tried their 360-degree spray extension in their lab, but we're not impressed and did not recommend buying it. We have the mechanism to advance an extension into the part, but can’t find a tip that will perform. W. M.
A. I’ve had extensive experience coating interior surfaces, but nothing that small in diameter. Unfortunately, I have no magic spray gun to recommend for this application. What you are dealing with here is Izzo’s First Law: “The innate perversity of inanimate objects.”
There are a couple things you can try. If you are using a 360º nozzle that sprays a disc shaped pattern perpendicular to the axis, try using a 360º nozzle that sprays a hollow cone at a 45º angle to the axis. Another approach is using a powdered version of the dry lubricant. Preheat the part and dip it into a fluidized bed of the material. I can’t think of anything other than those suggestions. Perhaps a reader can help.
Choosing the right conveyor system, coating technology, and ancillary equipment.
Masking is employed in most any metal finishing operation where only a specifically defined area of the surface of a part must be exposed to a process. Conversely, masking may be employed on a surface where treatment is either not required or must be avoided. This article covers the many aspects of masking for metal finishing, including applications, methods and the various types of masking employed.
Simply heating up the substrate does not cure the coating. There are many variables to consider when choosing the best cure oven for your application...