SanFran 12 Posted September 3, 2017 Share Posted September 3, 2017 Ali mast, keel stepped on to an ali plate on keel. Looks like electrolysis on base plate. White powdery stuff with pitting on the base plate. Any ideas why? Do I need to run an anode from the base plate into the bilge? Quote Link to post Share on other sites
Island Time 1,245 Posted September 3, 2017 Share Posted September 3, 2017 Pic please? Quote Link to post Share on other sites
SanFran 12 Posted September 3, 2017 Author Share Posted September 3, 2017 Maybe tomorrow... Quote Link to post Share on other sites
wheels 543 Posted September 3, 2017 Share Posted September 3, 2017 No it is corrosion. An Anode won't help. You need to clean it, etch and prime to protect it.Ali does that with Salt water if Salt gets to sit on it. You can totally solve the issue if you were able to remove the plate, and fit with an anodized one. But the base of the mast would be more difficult to do. So you may as well clean, etch and prime.Galvanic corrosion is caused when you have two dissimilar Metals touching. Isolation fixes that.Electrolysis is when you have two dissimilar metals submerged. Anodes fix that. Quote Link to post Share on other sites
SanFran 12 Posted September 4, 2017 Author Share Posted September 4, 2017 Thanks wheels. It wouldn't have anything to do with the boom track being attached with stainless Screws? There were nylon collars but the ss screws go into the mast itself. Quote Link to post Share on other sites
wheels 543 Posted September 4, 2017 Share Posted September 4, 2017 Thanks wheels. It wouldn't have anything to do with the boom track being attached with stainless Screws? There were nylon collars but the ss screws go into the mast itself. The issue you could have with that is the SST screw thread could fuse itself to the Ally and be a right pain in the A to get out. Good practice is to use a coating on the thread before you screw them in. Coatings such as lanacote, Tuffgel, or locktite usually isolate the materials. it is more about keeping the moisture out from between the two metal faces. As soon as water/salt gets between the surfaces, the corrosion starts. Any SST fitting needs to be isolated with some kind of plastic spacer or bedding compound to keep the moisture out and the surfaces apa, or the same will happen. Quote Link to post Share on other sites
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