Bronze cleat, aluminum boom

[Warren Kaplan]

I have to replace a few corroded cleats on my boom. I'm thinking of using bronze cleats...small ones. If I use a nice glob of LifeCaulk bedding between the bronze cleat and the aluminum boom as insulation, will I have a problem with dissimilar metals? I'll also put some LifeCaulk around the stainless steel mounting screws. Any problems with this?
Thanks
Warren



Setsail728@aol.com

[Larry DeMers]

There will still be contact by the threads cutting into the aluminum hole, which will conduct electricity, setting up corrosion, albeit slower than if no isolation were used. You might want to use a dielectric grease on the threads, as well as the Lifecaulk bedding compound (allow the lifecaulk to dry a bit before tightening the screws down. This will keep it from squishing out (another glorious technical term!) from underneath the cleat). While the threads will still be in electrical contact with the aluminum while using dielectric grease, the chemical makeup of this grease seems to be preventing the corrosion that normally would occur at the thread site when aluminum is in contact with the S.S. screws.
Did you see any corrosion of the aluminum when the cleat was removed? I would be concerned if it was more than a little bit.

Cheers,

Larry DeMers
s/v DeLaMer
Cape Dory 30

I have to replace a few corroded cleats on my boom. I'm thinking of using bronze cleats...small ones. If I use a nice glob of LifeCaulk bedding between the bronze cleat and the aluminum boom as insulation, will I have a problem with dissimilar metals? I'll also put some LifeCaulk around the stainless steel mounting screws. Any problems with this?
Thanks
Warren

demers@sgi.com

[Mark Yashinsky]

Dont know if Lifecaulk can be considered an antisieze compound. Another Cd'er (Goldsmith, Second Chance) has gone the Tef-Gel route w/ any screws into anything metal on his CD27. He has also put two layers of quality electric tape between anything metal mounting to anything metal (except for the screws). He had a lot of corrosion between the boom/mast and any other metal parts (stainless(!), and aluminum(!)). Most of the corrosion was of the attached part and not the boom/mast although the anodizing was breaking down in a number of area. While your at it, check any other metal attachments and their attaching device for corrosion.

[Art Pedersen]

When we commissoned our cd36 we took everything off the boom and mast and reinstalled them with thin mylar gaskets between the cleats, winches etc. I coated the screws with life caulk. Its been l0 years and we still don't have any corrosion. Its also a lot less messy than using bedding compound. I think you can get the mylar at art supply stores



pavnsail@aol.com

[Larry DeMers]

It absolutely is not an antiseize compound..I was not suggesting that, although my msg. could sure be read that way..sorry. No, I meant that the Lifecaulk should be used for the bedding, and an antisieze compound applied to the screw threads. Separate products entirely.

Larry DeMers
s/v DeLaMer

Dont know if Lifecaulk can be considered an antisieze compound. Another Cd'er (Goldsmith, Second Chance) has gone the Tef-Gel route w/ any screws into anything metal on his CD27. He has also put two layers of quality electric tape between anything metal mounting to anything metal (except for the screws). He had a lot of corrosion between the boom/mast and any other metal parts (stainless(!), and aluminum(!)). Most of the corrosion was of the attached part and not the boom/mast although the anodizing was breaking down in a number of area. While your at it, check any other metal attachments and their attaching device for corrosion.

demers@sgi.com

[Leo MacDonald]

I have to replace a few corroded cleats on my boom. I'm thinking of using bronze cleats...small ones. If I use a nice glob of LifeCaulk bedding between the bronze cleat and the aluminum boom as insulation, will I have a problem with dissimilar metals? I'll also put some LifeCaulk around the stainless steel mounting screws. Any problems with this?
Thanks
Warren

Hi Warren,

Yes, don't do it. The voltage potential between the aluminum & bronze with the mounting screws acting as conductors will start galvanic corrosion. Recommend stainless or aluminum cleats.

Fair Winds,
Leo



macdore@aol.com

[Bristol Bronze]

I have to replace a few corroded cleats on my boom. I'm thinking of using bronze cleats...small ones. If I use a nice glob of LifeCaulk bedding between the bronze cleat and the aluminum boom as insulation, will I have a problem with dissimilar metals? I'll also put some LifeCaulk around the stainless steel mounting screws. Any problems with this?
Thanks
Warren

Dear Warren,

Any contact between dis-similar metals is potentialy dangerous. Non-conductive materials can help but if it is not done right it could cost you a new boom. I have customers wanting to do the same thing that you are all the time. The best way would be to make a small wooden pad or island out of some nice nautical wood such as teak. Attach the pad to the boom with stainless steel screws and attach the Bronze cleats to the pad with Bronze screws. I have had a number of customers do this with great success.

Roger W.
Bristol Bronze
401-625-5224



rogerw@meganet.net

[Warren Kaplan]

Thanks all for the help. I haven't mounted anything yet but I'll consider all suggested. I noticed in this year's West Marine Catalog 2001 on pg 948 that they also show nylon and Maralon cleats. Seems to me that these would eliminate corrosion other than that between the mounting screw and boom. I've never used these cleats but nobody suggested using them. Are they weak under load as compared to similar sized metal cleats? Ugly? Do they melt in the hot sun? What's the "knock" on these type cleats?
Warren
S/V Sine Qua Non



Setsail728@aol.com

[Leo MacDonald]

Thanks all for the help. I haven't mounted anything yet but I'll consider all suggested. I noticed in this year's West Marine Catalog 2001 on pg 948 that they also show nylon and Maralon cleats. Seems to me that these would eliminate corrosion other than that between the mounting screw and boom. I've never used these cleats but nobody suggested using them. Are they weak under load as compared to similar sized metal cleats? Ugly? Do they melt in the hot sun? What's the "knock" on these type cleats?
Warren
S/V Sine Qua Non

Hi Warren,
The nylon or Maralon cleats would be an option. The 'knock' might be dependent on the load. The ones I have seen are two bolt affairs. (No melting and are a black color, looks like aluminum.)
Fair Winds,
Leo MacDonald, Heather Ann CD30K



macdore@aol.com