Pitting, those small holes that form in metal, is a type of corrosion caused by a process called depassivation. Depassivation involves the deterioration of protective coatings around a metal due to contact with a chloride. In the case of aluminum on a boat, the main culprit for pitting is salt water. Listed below are some tried and true methods for removing this common and annoying corrosion that has plagued many a boat owner.
Step 1: Wash
Start by rinsing off all the dirt from the aluminum surface. A power washer can be pretty useful for blasting away grime, but you can also use a hose. Next, wash the surface with a soap that has mild alkalinity. Common dish soap can have high alkaline levels that might end up stripping the wax off of the surface you’re cleaning. Once you’re finished washing, thoroughly dry the surface with a microfiber towel.
Step 2: Abrade
The next thing you want to do is remove the corrosion. Listed below are a few different methods you can try:
- Method 1: Dry Sanding– Begin with a higher grit (200-400) sandpaper and work your way to a finer grit (600-800). Use the more abrasive sandpaper to remove the deep pits, and then switch to the finer paper. Do two or three rounds of sanding, using finer grit than the last for each round.
- Method 2: Wet Sanding– Some people prefer to use a wet sanding method for pitting removal, because it does not produce as much dust and does not clog the sandpaper as often as dry sanding. For this method, sand using sandpaper specifically for wet sanding (dry sand paper will fall apart). Start with a grit of around 200-400, mix a bowl of water with a few drops of dish washing liquid, wet the paper, and sand the pitting off the aluminum. Finish using a fine grit of around 600-800 (just like the dry sanding method).
- Method 3: Razor blade– Some boat owners prefer to use a razor blade to scratch off hard to remove pitting from aluminum. For this method, take a straight razor blade and lightly scratch off the damaged areas.
Step 3: Buff
Use a rotating buffer or fine steel wool and buff the sanded area. Rub the surface until it appears smooth and free of all pitting. If you still have problem spots repeat step 2. Finish by wiping off all debris with a clean microfiber towel.
Once you’ve smoothed out the aluminum surface apply an aluminum polish and sealer using a clean cloth. BoatLIFE’s aluminum cleaner is a very effective aluminum polish and protectant, that not only brightens, but defends the aluminum from further oxidation and pitting.
Do you have a method for the eradication of pitting? We’d love to hear about it! Please leave a comment in the comments section or shoot us an email. Be sure to grab some BoatLIFE aluminum cleaner and start fighting corrosion today!