Corrosion Question

[Sitkaspruce]

Was doing the usuall spring clean and wash and when I took off my side windows, two snaps came off the side of the boat and the rest are corroded as well.

and this is bad one, it is down a few mm into the metal.

Any ideas on what is causing this?? And how can I clean up and avoid this for the rest?? It is also starting to form around my windows, inside and out.

Boat is stored outside, in the yard all year long and is washed after every trip out on the salt.

Cheers

SS

 

[spring fever]

That looks like galvanic corrosion-which is caused by 2 disimiliar metals coming in contact with each other in the presence of salt water. Essentially you have a battery with the salt water acting as the electrolite. Don't think you can totally get away from it but you would lessen the effects if you isolated the metals-say with a ruber or similiar gasket-good paint-can't remember the yellow paint-some kind of oxide. You might try a different type of fastener-say with an aluminium shaft-I.m assuming that your boat is aluminium.

 

[casper5280]

That looks like galvanic corrosion-which is caused by 2 disimiliar metals coming in contact with each other in the presence of salt water. Essentially you have a battery with the salt water acting as the electrolite. Don't think you can totally get away from it but you would lessen the effects if you isolated the metals-say with a ruber or similiar gasket-good paint-can't remember the yellow paint-some kind of oxide. You might try a different type of fastener-say with an aluminium shaft-I.m assuming that your boat is aluminium.

X2 you could remove them all and then wire brush the area and reinstall. You can use heavy tar paper as a gasket and trim it with a sharp knife. I have seen guys use this between there leaf springs and the trailer frame works great.

 

[salmonkiller01]

Use etching primer, it is for aluminum, then paint. Nothing is forever for protection but a proper clean-up and paint and it will last

 

[Gypseas]

That is crevice corrosion. some good reading here http://www.ifish.net/board/showthread.php?t=110222&highlight=aluminum+corrosion

Best to have bare aluminum than painted imho. Had a bit of it with my hewescraft
cheers

 

[Bows Up]

Vinegar and water wash then what salmonkiller said. Cdn Tire sells etching primer.

I think if you run aluminum, it is almost unavoidable.

 

[Sitkaspruce]

Thanks for all the info and links guys. Will follow up with what has been recommended

And yes it is an aluminum boat.

Cheers

SS

 

[NautiGirl]

This can happen anywhere on your aluminum. remove the snaps, buff it down, acid/vinegar wash it, then touch it up with epoxy, which will act as a corrosion barrier to keep the dissimilar metals apart and keep the corosion away next time. check any bilge areas regularly too and when doing any wiring never let any little copper wires drop into the bilge where they can sit in salt water touching the aluminum. they will burn little holes in the bottom of the boat, or cook partway through and roll around pitting your hull. Never lose a penny or a dime from your pocket, and try not to lose any hooks or swivels that will find a salty wet spot to etch into. Vaccuum any bilge areas regularly. I removed my entire floor and lined the inside of my boat with flexible epoxy to guard against corrosion, fill some pits, and to lock tight all my rivets.

 

[staying alive]

Read the article ------now I hate crevice corrosion --------will have to give me boat the once over ----all the problems appear to be where snaps are probably drilled in after the boat was painted which is logical I guess your are not going to mount all the canvas then take apart and paint all the holes then re-install that is something we get to do. I was impressed when I lifted my floor boards and saw the inside of the hull was completely painted. I like my exterior paint job now I guess I have something new to maintain.

 

[Last Chance]

Those looke like aluminium rivets to me, so you have crevice corrosion. I would probably fine a nice way to make a nice bare piece paitn free around them rather then keep coating, will be a loosing battle.