Mast shoe question - corrosion prevention

JoJo - SV Uku

New member
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Arizona
I've got a deck stepped mast. The aluminum mast slides into an aluminum shoe (think mortise and tenon), pretty standard setup.
I'm wondering if it would be prudent to coat the shoe with some Loctite LB8023 that I have on hand... Yay or nay?
I'm sure it isn't necessary but also figure out couldn't hurt. Or could it?

20221123_110335.jpg
 

mgs

canoeman
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maine
I wouldn’t do it. It’s aluminum on aluminum the corrosion will be from something else. That Loctite has some other metal in it and is a right bear to keep things clean.
 

El Borracho

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Pacific Rim
Well … @slug zitski and @mgs that LOCTITE 8024 has NO metal in it. (Ask me how I know) :)

As for helping the mast shoe? It might. Probably not. Apply monthly? Not likely.

Where aluminum fits tightly it is going to corrode because it wears, is wet, etc. Many boat parts are meant to be renewed after a few decades of service. A new shoe and a refreshed mast foot are not uncommon.
 

slug zitski

Super Anarchist
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Well … @slug zitski and @mgs that LOCTITE 8024 has NO metal in it. (Ask me how I know) :)

As for helping the mast shoe? It might. Probably not. Apply monthly? Not likely.

Where aluminum fits tightly it is going to corrode because it wears, is wet, etc. Many boat parts are meant to be renewed after a few decades of service. A new shoe and a refreshed mast foot are not uncommon.
I get in the habit of using tefgel on all metal mating surfaces …probably not needed
 

mgs

canoeman
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272
maine
Well … @slug zitski and @mgs that LOCTITE 8024 has NO metal in it. (Ask me how I know) :)

As for helping the mast shoe? It might. Probably not. Apply monthly? Not likely.

Where aluminum fits tightly it is going to corrode because it wears, is wet, etc. Many boat parts are meant to be renewed after a few decades of service. A new shoe and a refreshed mast foot are not uncommon.
You expect me to read carefully?
 

El Borracho

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The ingredients of Loctite LB 8023 are listed in its MSDS.

Is there a chemist in the house to interpret it?
Tar, grease, soap, graphite and quicklime. Interesting. Graphite and aluminum are at opposite ends (bad) of the electrochemical series, right? That seems suspicious. But graphite is common in other goops. Quicklime is a voracious consumer of moisture. Like plaster. Whatever quicklime does in that concoction will be over in a few hours on a wet boat.

Complicated chemistry. I’d stick with lanolin or Tef-Gel. They seem more inert. Less active.
 
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longy

Overlord of Anarchy
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San Diego
First - make darn sure that water can drain from inside the mast. Second - once the mast is stepped, fill the crack between the spar & the base with silicone, get it as far into the joint as possible. Why silicone? it's waterproof, low strength, & does not conduct electrons.
Water & (especially) salt are what will cause corrosion
I watched a yard crane trying to pull the rig out of a Columbia 50 which had the same set up but down in the bilge (keel stepped). They had lifted the boat up a foot where the crane could not lift any more. They attacked the joint with a gas torch, they beat it with sledges. Finally they had to cut the mast just above the step cup.
 

slug zitski

Super Anarchist
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Hm
First - make darn sure that water can drain from inside the mast. Second - once the mast is stepped, fill the crack between the spar & the base with silicone, get it as far into the joint as possible. Why silicone? it's waterproof, low strength, & does not conduct electrons.
Water & (especially) salt are what will cause corrosion
I watched a yard crane trying to pull the rig out of a Columbia 50 which had the same set up but down in the bilge (keel stepped). They had lifted the boat up a foot where the crane could not lift any more. They attacked the joint with a gas torch, they beat it with sledges. Finally they had to cut the mast just above the step cup.
hmm

ive seen hoist issues with Spar tight

crane lifted the mast and the boat came out of the water

imbedding a “ cheese cutter “ cord into the pour ,to saw split the spartight Chocking , is standard , especially when the partner walls might form an upside down funnel shape

and water drainage at mast butts , steps is very important

drill another hole in the mast , mast step if you think it’s needed

as to the tefgel , locktiite, coating …before all these speciality products became available aluminum was protected with Lanolin

works well..
 
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SloopJonB

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Great Wet North
Something that hasn't been mentioned is to change the shoe from a cup the mast sits inside to a cruciform base that sits inside the mast.

I had to build a new step for my Columbia 43 and did it like this;

18c Mast step after.jpg


Due to the corrosion from the existing cup style step the foot of the mast needed to be trimmed to eliminate the corrosion so I increased the height of the new step block by a corresponding amount.

The alloy plate cruciform fits inside the tube and was scuppered in the corners to eliminate standing water. Much better than sitting inside a cup.
 

SloopJonB

Super Anarchist
70,051
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Great Wet North
many layers of ply and glass mat laminated with epoxy.

Just for fun, here's what it replaced.

That mess actually kept the mast standing for a trip by the PO from Santa Monica to San Rafael.

17a Mast step before.jpg
 

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