Fluffy White Corrosion In Cabin

dread

New member
I have a 2006 25' Cruiser. Suddenly this year (I bought it in 2012 and moved it from SoCal to the Bay Area - kept at the dock both places) there was fluffy white corrosion where one grommet screws into the window frame. The white fluffy powder falls down and collects on the shelf below the window. Then the same kind of corrosion appeared on two cockpit cushions stored in the v-berth, where the tab meets the zipper. What's going on, and what do I do about it? I tried removing the screw and putting silicone sealer in the hole, hoping that it would separate incompatible metals, but it hasn't helped. I keep the boat attached to shore power. Would that have an impact?
 
From what you describe, the wind frame is aluminum, and there may be a Stanless steel screws. Generally these types of corrosion are just from the salt air and the dissimilar metals. The forward cushion, sounds like an aluminum zipper slider, which is common, even thought the zipper teeth are plastic . Salt water will cause corrosion of unprotected corrosion. In this case, it is not related to either DC or AC power. Unfortunately the zipper slider can be ruined and make the zipper useless. I use a dry silicone lubricant, and then sipper grease to keep the zipper teeth and slider from fusing with corrosion. Working the zipper regularly helps to prevent this. Keeping salt water off, or salt spray (even salt in the air) will help to speed this corrosion.

As for the aluminum frame, I would remove the screw, clean up the aluminum with a small SS brush (in a Dremel tool, may be best), and then try to paint it. If there is significant metal loss, then I would clean the aluminum, fill the damaged part with Marine Tex, and smooth and fair the epoxy, and then drill new holes, and put the SS crew (304 alloy is best) with a never seize compound. Wash the boat well after each exposure to Salt water.
 
For isolating dissimilar metals (aluminum and steel, for example), if I have a larger flat surface (like a hardware base), I'll use a sheet of thin plastic. But for small fastener connections, there is an isolating compound you can use called "Tef-Gel." Good stuff, in my experience.
 
I had a the same problem, removed all screws from window frames and replaced with new ones coated with Tef Gel, problem solved!
Roger
 
Thanks for the suggestion. I ordered some online. When it came, it was labeled "thin" -- almost as if were written on the label with a sharpie. The official website says "thin" is also available, but I wonder if "thin" will have the viscosity and durability that I want. Any thoughts?
 
I would stick with the regular kind, it's a pretty stiff gooey product that comes with a small bristle brush for application. Be sure to get it up under the head of the screw where it makes contact with the aluminum. I used Truss Head Phillips screws.
Roger
PS: I did have 3 of the old screws break off rather than come out, not bad when you consider how many screws there are!
 
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