Have you done any research on the best means of cleaning an aluminum mast? Im having other work done to mine and thought it would be a good time for a cleaning.
Bob Pendleton
Via e-mail
If your mast just needs a good cleaning and polish, then a non-abrasive cleaner/wax will work fine.
Our most comprehensive report on cleaner-polishes was Metal Cleaners (PS June 2006 online), in which we tested 16 different products. Wed opt for one of the liquid cleaner-waxes like Collinite No. 850 Metal Wax, a non-abrasive cleaner-wax is in the same family as Collinite No. 885 Marine. Other products that matched the Collinites performance in restoring and protecting metal were Meguiars Mirror Glaze Professional All Metal Polish, Mothers California Gold Chrome Polish, and Star brites Chrome and Stainless Polish. Star brite also makes Ultimate Aluminum Polish, which we have not yet tested.
There are more than a dozen such products on the market, but we can’t speak to their effectiveness. Avoid using a power tool for this job, and steer clear of abrasive cleaner/polishes. The anodized surface is very durable, but over-aggressive polishing will shorten its life.
If your mast is extremely weathered, you might consider coating it. While coating aluminum is tricky, its not too difficult for a confident do-it-yourselfer-or a classic car enthusiast who has restored a few old MGs.
There are two approaches here. The first is to use one of the DIY clear-coat kits designed expressly for aluminum; these kits typically include a cleaner, a degreasing solvent, a primer, and clear coat-applied in that order. The second option is to use a high-quality linear polyurethane (LPU) paint.
We have not tested any of the clear-coat kits. However, based on our experience with similar products, clear coating would be a two- to three-year solution, where as an LPU job can last 10 years or more. For both of these projects, the bulk of the labor is in the meticulous prep work required, so the longer-lasting LPU makes more sense to us.
Prepping the mast for LPU is a big project. For a proper job, youll want to remove as much hardware as possible. Then you need to wash, degrease, and prime (typically with a zinc-chromate primer) the surface before painting. Applying an LPU is not much different than painting a hull.
The Inside Practical Sailor blog post online Painting Your Boat Like a Pro (posted Oct. 5, 2016) has links to our LPU paint tests and related how-to articles. Marine-maintenance guru Don Caseys This Old Boat covers the basics of LPU painting as well and is available in PSs online bookstore.
It is important to remember that when you re-install any mast hardware, the hardware and screws or rivets must be isolated from the painted aluminum. For bedding, use a UV-resistant polyurethane sealant; for rivets (monel is preferred) or screws, most riggers use Tefgel, Tuffgel, or Duralac. If you skip this step, the paint will fail at the hardware interfaces within a couple of years.
If you have the funds to hand the project to a pro, you could have the mast re-anodized. Unpainted masts are protected from corrosion through anodizing, an electrochemical process that converts the metal into a shiny, anodic oxide finish.
Most cities will have an anodizing facility, but anodizing requires that the mast be immersed in an acid-electrolyte bath, and not all of them will have a tank to fit a mast. Charleston Spars, in Charleston, S.C., has a large facility that specializes in masts, and there are others around the country that also do this work-but youll definitely want to get references.
Powder-coating the mast (often with anodizing) is an option, and you can find powder-coating services in almost any big U.S. city. The facility you choose should have plenty of experience in powder-coating surfaces for the marine environment; Charleston Spars also does this work.
Collinite 850 says “medium cut”, doesn’t that mean it is abrasive so not suitable for a mast?