Salt Water and Aluminum

[rpatton]

Simple question. Does saltwater hurt or corrode aluminum.

 

[GA_Boater]

Not with proper protection. Plenty of aluminum boats sail the Seven Seas.

 

[dls322]

Yes, it does. Even the salt in the air will corrode the aluminum on your boat. After dealing with disasters with saltwater and pontoons i am under the opinion they do not belong in salt water.....coat it with as much stuff as you want, it will still splash up and cause issues....think of it as placing your boat in acid

 

[dingbat]

Salt water DOES NOT corrode aluminum!

You may have noticed that you never see aluminum corrosion in lakes, pools, food packaging products, etc. Typically, if you have seen corroded aluminum, it was in or near the ocean. While it may seem logical to draw the conclusion that the salt water must be corrosive to the aluminum, it is not. Salt water does not corrode aluminum because of its neutral pH. A saltwater solution can, however, be a major facilitator for galvanic or dissimilar metal corrosion, a more complex corrosive process.

http://sheetpileeurope.ch/uploads/CMI technische documenten (engels)/aluminum_corrosion.pdf

 

[Capt Sully]

Not with proper protection. Plenty of aluminum boats sail the Seven Seas.

Yep, even Stealboats in the Seas.

 

[WaterDR]

Salt water DOES NOT corrode aluminum!

You may have noticed that you never see aluminum corrosion in lakes, pools, food packaging products, etc. Typically, if you have seen corroded aluminum, it was in or near the ocean. While it may seem logical to draw the conclusion that the salt water must be corrosive to the aluminum, it is not. Salt water does not corrode aluminum because of its neutral pH. A saltwater solution can, however, be a major facilitator for galvanic or dissimilar metal corrosion, a more complex corrosive process.

http://sheetpileeurope.ch/uploads/CMI technische documenten (engels)/aluminum_corrosion.pdf

Salt water actually is a required ingredient to "crevice alum corrosion" which can cause a boat to fall apart.

You are correct that the safe pH for AL is between 7 and 9, but that does not mean that it can't corrode in different ways such as pitting, crevice, and under deposit corrosion. All conditions that happen in salt water and where salt water can accelerate the process.

 

[WaterDR]

Keep in mind that Aluminum corrodes to AL(OH)3 which forms a protective barrier to further corrosion. If any part of the metal surface can not form this layer (which is what happens under a crevice), than that unprotected area becomes anodic. Because the majority of the surface is covered in Al(OH)3, you have the perfect formula for a disaster....a very large cathode and a very small anode. When this happens, you have rapid metal loss at the anode and BAM. Trouble. Salt water is an ingredient to fuel the reaction. No salt water, no reaction. Its the conductivity of the water that's the problem. Not the pH.

 

[dls322]

Salt water DOES NOT corrode aluminum!

You may have noticed that you never see aluminum corrosion in lakes, pools, food packaging products, etc. Typically, if you have seen corroded aluminum, it was in or near the ocean. While it may seem logical to draw the conclusion that the salt water must be corrosive to the aluminum, it is not. Salt water does not corrode aluminum because of its neutral pH. A saltwater solution can, however, be a major facilitator for galvanic or dissimilar metal corrosion, a more complex corrosive process.

http://sheetpileeurope.ch/uploads/CMI technische documenten (engels)/aluminum_corrosion.pdf

Are you splitting hairs? Yes, it does facilitate corrosion. Lets compare 2 of the same aluminum pontoons, one docked in saltwater and the other in fresh. After 3 years which one has more corrosion....saltwater guaranteed. Why to people apply special paint to the toons to protect them from saltwater, if saltwater does not corrode? I am at a loss with this logic. Having owned a pontoon used in salt and another used in fresh, I do know the horrors saltwater can have on aluminum

 

[staydry]

Going on the 9th year of ownership...live well hinges completely disintegrated ...alum perimeter trim separating floor from railing has severe pitting but only on the rear of the boat..... toons themselves, railing, bimini all in great shape..... think they must use different grade alum for diff applications...mainly saltwater use....