Uploaded October 2020 | Updated September 2026, 1 week ago
Complete instructions on how to fix a corroded propeller that has been used on a rescue vessel in salt waters for 18 years. The outboard propeller was sitting on a Tohatsu that uses identical propellers to Honda, Suzuki, and Evinrude motors.
The first steps show that sandblasting with aluminum oxide is a great way to clean off not only dirt but also the small fragments of white paint that were still left on the propeller, the propeller was then exposed put into an alkaline wash containing mainly potassium and sodium hydroxide, providing a pH over 10. This reaction only needs to start and one will see how effectively these alkaline chemicals etch the surface when the hydrogen gas is evolving. The same reaction can be made with traditional sodium hydroxide toilet cleaner from the supermarket. After the alkaline etching that removes all the grease and organic dirt/residues, then the propeller was rinsed and brought into a nitric acid bath with only 20% concentrated nitric acid. Here the reaction shows only vaguely as some harmful nitrous gas may be formed so good ventilation is always required when one uses nitric acid in similar cleaning operations, as always. Nitric acid is also possible to purchase in hardware stores and there is no need to have any super-strong acid since also a weaker acid will allow the dissolution of aluminum oxide on the propeller surface. The acid etching made the propeller surface super smooth and at this point, all finger contact should be avoided since it would inevitably grease the propeller instead was up for a zinc powder coating primer before the chrome powder coating was applied.
A few words of advice: all propellers have a rubber section inside them, alongside the splined tubing. This is heat-sensitive to some extent so it’s recommended to avoid leaving the propeller in the oven for more than the required time to cure the powder coating. Du to the very heat conducting nature of aluminum, this was not a problem since it easily reached 180 Celsius in 3 minutes in the oven, while the rubber takes more time.
Please post any questions, and Good Luck with your propeller restoring. Following the instructions in this video will make your propeller look like new. If I would do it again, I would coat a thinner layer with the powder coat. That was the lesson learned and the issues with coating slightly too much can be seen in the less uniform coating on some spots of the blades in the final sections of the video.
All the best and have a nice day!
#restore
#boat
#propeller
#KenSweden
Complete instructions on how to fix a corroded propeller that has been used on a rescue vessel in salt waters for 18 years. The outboard propeller was sitting on a Tohatsu that uses identical propellers to Honda, Suzuki, and Evinrude motors.
The first steps show that sandblasting with aluminum oxide is a great way to clean off not only dirt but also the small fragments of white paint that were still left on the propeller, the propeller was then exposed put into an alkaline wash containing mainly potassium and sodium hydroxide, providing a pH over 10. This reaction only needs to start and one will see how effectively these alkaline chemicals etch the surface when the hydrogen gas is evolving. The same reaction can be made with traditional sodium hydroxide toilet cleaner from the supermarket. After the alkaline etching that removes all the grease and organic dirt/residues, then the propeller was rinsed and brought into a nitric acid bath with only 20% concentrated nitric acid. Here the reaction shows only vaguely as some harmful nitrous gas may be formed so good ventilation is always required when one uses nitric acid in similar cleaning operations, as always. Nitric acid is also possible to purchase in hardware stores and there is no need to have any super-strong acid since also a weaker acid will allow the dissolution of aluminum oxide on the propeller surface. The acid etching made the propeller surface super smooth and at this point, all finger contact should be avoided since it would inevitably grease the propeller instead was up for a zinc powder coating primer before the chrome powder coating was applied.
A few words of advice: all propellers have a rubber section inside them, alongside the splined tubing. This is heat-sensitive to some extent so it’s recommended to avoid leaving the propeller in the oven for more than the required time to cure the powder coating. Du to the very heat conducting nature of aluminum, this was not a problem since it easily reached 180 Celsius in 3 minutes in the oven, while the rubber takes more time.
Please post any questions, and Good Luck with your propeller restoring. Following the instructions in this video will make your propeller look like new. If I would do it again, I would coat a thinner layer with the powder coat. That was the lesson learned and the issues with coating slightly too much can be seen in the less uniform coating on some spots of the blades in the final sections of the video.
All the best and have a nice day!
#restore
#boat
#propeller
#KenSweden
