I was fortunate to have the finishing shop available to me this Sunday. We normally run six days a week. I showed up at about 5:00 am so I would have enough time to prepare the parts before the painter showed up. I'm qualified to run nearly all the processes in our shop except for Shot Peening and Painting. Shot Peening requires certified operators and good painting technique is a learned art. The first step in preparing for the Alodining of all of the cabin sheet metal is to remove all oils and ink markings. I accomplished this by an immersion alkaline cleaning followed by a 3-stage flowing rinse. After verifying a water-break-free surface the parts are then alkaline etch cleaned. After rinsing the parts are immersed in a nitric acid desmutter/deoxidizer. The etch process imparts a black smut to the surface that the deox removes. In order to get the best Alodine job the etch and deox step is necessary. Aluminum when left exposed to an oxygen environment will develop an aluminum oxide layer that serves to protect the substrate. This layer must be removed so that the Alodine can chemically react with the surface. If you are not fortunate enough to have access to a process line, Scotch-Brite, elbow grease and MEK will also work
