The most common questions I receive pertain to what polish products I use and what specific techniques I use with those products. The truth is that I have used a variety of different products over the past half dozen years and my techniques have evolved and continue to evolve. Nevertheless, there is a common theme with many of the aluminum polishing systems.
Each of the systems I used have several “grades” of polish ranging from a coarse grit, to a less abrasive grit to a finishing product that is used for the final step. The actual number of individual grades varies from as little as three to as many as a half dozen. The specific grade you begin with depends on the condition of the metal at the time you begin the process. The coarsest grits are generally used for airplanes that have not been polished for an extended period of time or for removing scratches and other imperfections.
In general, the grades of polish prior to the final step are applied with a variable speed automotive style 7 inch buffer with a wool buffing pad. The final step in the process is normally performed with an orbital buffer, preferably a dual head buffer like the Cyclo. Following the specific procedure recommended by the polish manufacturer is obviously a good initial approach. Those techniques can be refined and even modified as you become comfortable with the polishing process. Like most learned skills, you need to be able to walk before you can run. Becoming really proficient requires practice and a reasonable degree of experimentation to see what works best for you.
Following are a couple of key items I have learned while polishing NC17634.
- There is a tendency to move to a less coarse grade of polish prematurely. When you do so, it is unlikely the next grade of polish will improve the situation.
- Never allow any traces of one grade of polish to be carried forward into the next step. The best way to assure this happens is to thoroughly clean the surface with mineral spirits after each step in the process.
- What works today on one section of the airplane may not work equally well tomorrow on the next section. If you are working on an older airplane, there is a reasonable chance certain sections of skin have been replaced in the past. Many of the aluminum alloys used in the 30’s and 40’s are no longer manufactured. That leaves the possibility that some sections of your airplane have one aluminum alloy and other sections have a different alloy. With appropriate effort, they can be made to appear identical, but the process for getting to that point many be different from section to section. Your techniques may also need to be tweaked slightly when working in cold or humid conditions.
- If what you are doing isn’t working, continuing to do the same thing will probably not make things any better. In most instances, you will likely find that you need to go back one or more steps in the process. That is particularly difficult to do when you are in the final stages, but it may be unavoidable.
- Make a concerted effort to use the quantity of polish recommended for the particular system you are using. Polish is most effective as it is heated with the buffing action – – the last few seconds as it disappearing from the metal. Too much polish prolongs the time it takes to get to that point, creating some needless effort.
- CAUTION – – While the preceding item indicates it is necessary for the polish and the metal to get warm during the polishing process – – DO NOT LET IT GET SO HOT THAT IT BURNS THE METAL! Touch the metal frequently with your hand to test the temperature. If it is getting too warm for you to touch it, stop polishing and let it thoroughly cool.
- While you will be polishing the airplane indoors, don’t wait until you are finished before you bring it out into the sunlight. The harshness of the sunlight will show every flaw. It is much better to pull it out into the sunlight on a regular basis to check your polishing progress.