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How to remove heavy mineral deposits from pontoons.



Kevin Sageman
OCP – Oxford County Pontoon and Powersports Inc. asked:

Like most pontoons that don’t get cleaned on a regular basis we have a few in stock that have a lot of mineral build up on the bottom half, below the waterline, of the tubes, which cleaner works best and how well will it work on mineral build up in some cases looks like concrete.


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Mineral build up from lack of prevention and poor maintenance is similar to limestone or marble. The prime components are calcium and magnesium, which are difficult to remove. Strong acids can dissolve this, if allowed to work for long periods of time and if kept wet or immersed. The problem is that these acids also attack aluminum and can often eat through the aluminum before the limestone and of course it’s impractical to build an acid bath so that the pontoons can be immersed in the acid for long periods of time.

The only solution for removal that we know of to-date is abrasion with sandpaper. We recommend wet sanding over dry to reduce dusting and to get better life from the sandpaper. It’s important to sand horizontally with the grain so that if any scratching of the pontoon takes place is will be less perceptible. 600 to 800 grit will be close to the mill finish grain in the aluminum. If you have heavy build-up, you may want to start with a more coarse grit to knock down the heavy stuff and switch to the finer grain as you get close to the metal. When you get close to the metal, you won’t be able to get the growth out of the grain without severe metal removal so when the metal starts to peek through, finish the job with Algex bottom cleaner made for cleaning aluminum. Spray it on, let it work for 20 to 30 minutes and pressure wash it off.

When sanding use a pneumatic linear sander to save time and your arms. It’s a lot of work. If you must do it by hand, use a long board.

After you get the pontoons clean, it’s a good idea to restore the finish by removing any stains and streaks and protecting the aluminum against future marine growth and staining. It’s just too much hard work doing this job each year otherwise. If mineral deposits are a common problem in your area, I suggest that you sell a protection package to all of your customers ASAP. They will thank you for it.

To remove stains and streaks, you may be able to simply spray on Alumabrite CBX and rinse it off to reveal the original aluminum finish. Alumabrite CBX is a marine grade aluminum brightener that turns the aluminum silver, instead of white like industrial cleaners.

If the aluminum is still stained, for example from acid washing, or streaked from improper cleaning, salt pitting or staining from industrial pollution, you will need to buff them with Alumabuff until shiny again. With Alumabuff and a linear buffer, you can typically buff out a pontoon in less than 60 minutes.

Once restored, protect them with Alumetron and VS721.

Alumetron is a protective clear coat that can last up to 10 years and comes with a 5 year warranty. It’s easy to apply and no special equipment is required. Just wipe it on and let it dry. It will resist staining and can withstand attack from strong acids. It keeps the pontoons clean and shiny for many years with a minimum of maintenance.

VS721 is a clear protective, super slippery coating that resists the attachment of marine growth and makes clean up much easier. When slime starts to form on the pontoons, if you wipe the slime off with a sponge, the pontoons will remain free of marine growth and mineral deposits. If the pontoons are not maintained, cleanup is usually a matter of pressure washing. VS721 is an annual application.

Protecting the pontoons in this way will prevent the heartache of trying to clean and restore them every year. For you convenience, use our Pontoon Calculator to determine the square footage that you need to work with and the quantity of products that you will need.

We can supply complete kits of product or Starter Packages for Marine Dealers. Call our order department at 1-866-214-3444 for more information.

Thanks for your question,

Captain Aurora
Richard Kittar

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