So with the powder coat colors chosen for the CB160 engine is was time to start the coating process on the good engine components. The plan was to shoot the cylinders, head, and valve cover with matte black. The upper and lower engine case will go HD bead blast silver and the side covers will be colored with anodized aluminum.
I am still very new to the whole powder coating process and have learned quickly that one similarity between anodizing and powder coating is the extensive prepping process required to ensure good results. In the case of the engine components I want to ensure that everything is out gassed and then surface prepped properly.
The first step involved an extensive amount of good old fashioned cleaning using a solvent tank and pressure washer. Once I had as much grease, oil, and dirt off the components as possible I proceeded with the out gassing. I fired the powder coating oven up to 550 degrees Fahrenheit and baked all the engine components for 2 hours. It was certainly evident from the smoke and the oil that leeched out that the out gassing process was accomplishing its intended task. I made sure that I bolted the cylinder to the cylinder head before out gassing in order to prevent the cylinder sleeves, and head inserts, from coming apart.
Once everything was out gassed I headed over to the glass bead blast cabinet. With all the important casting sections either taped off or plugged I proceeded with blasting everything clean. As with anodizing it is important to ensure that none of the blasted components have oil on, or in, them as the blasting tends to drive the oil and grease further into the pores resulting in a failed finishing process. This is why the out gassing is performed before the blasting.
With the blasting completed it was time to give everything a major bath and scrub it all down with hot soapy water. Once clean the time consuming process of taping off, and plugging, of crucial sections of casting could begin. Components with gasket surfaces got taped using high temp tape and all the bolt holes, and studs, were covered using silicone plugs.
I wanted to lay the powder onto the finned engine components with the fins in a vertical position. If I sprayed the powder onto to them horizontally I feared that I would get too much powder build up in between the fins. I welded up an adapter that would allow me to suspend the head and the cylinders vertically and would also give me a way to rotate the assembly as I sprayed.
So with all the prep work done there was nothing left to do except lay on the powder and hope my rookie endeavor will experience a successful outcome. Over the course of the next few evenings I was able to get through all the engine components and complete the coatings. There were lots of lessons for me to learn and some flaws in the coating that defines my ability however overall I am very pleased. The finishes all flowed out nicely and the overall effect is great. The coverage is good and the color was what I expected.
So with all the engine components now coated I will be able to send the cylinders and the head out for machining. While waiting for their return I should be able to start reassembling the bottom end.