Aluminum Corrosion

bayhoss

bayhoss

Member III
When refitting the mast on my 28 I noticed that the tapped holes that hold the top pulley assembly for the jib and forestay in place were lacking in strength. So I used two plates of drilled and tapped aluminum behind the mast (on the inside) to reinforce the attachment. In my haste I forgot to use anodized aluminum. I've had people say that with the aluminum inside the mast and 35' up from the water, little or no corrosion should take place. Others (myself included) feel that there is plenty of salt in the air 35' up and corrosion is a concern.
Any imput would be greatly appreciated.

Best Always,
Frank
E28 Valinor
 
Loren Beach

Loren Beach

O34 - Portland, OR
Senior Moderator
Blogs Author
Over the years I have used silicone sealant to isolate metals from each other on spars, and over a larger surface, a piece of thin mylar.
One place the corrosion starts is always around the fastenings, especially ss into alum.

Altho, anytime you put metal against other metal, with salt getting in, or even just atmospheric (acidic?) crud in my fresh water environment, the interface will show oxidation when pried apart years later.

I can say for sure, based on personal experience, that fittings that I have bedded in a lot of silicone sealant on the spars came apart totally clean after over a decade. Keeping all moisture and contaminants out the interface must be the most important part.

As they say, YMMV.

Sidebar: Perhaps not so much has changed in last couple hundred years, after all... Our ancestors had to take extraordinary measures to "keep their (gun)powder dry" and with modern highly-refined metals the advice is still similar.


Loren
 
bayhoss

bayhoss

Member III
didn't get the flavor

Got the aluminum from a friend - wish I knew more. Do you know a source for tel-gel?
Best,
Frank
 
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