Spreader advice please.

[JeremyFowler]

I removed the SS “bracket” that holds the 2 spreader arms as I was worried there might be a lot of corrosion problems underneath. There was only a bit.
Now, to re-instate do I:
1. Apply tape to the mast under the bracket to insulate to stop galvanic corrosion?
2. Use any insulating silicone or whatever as well?
3. Only use monel blind rivets, or are SS also ok?
Next question I will put in its own entry.
Cheers!

[nuku34]

I'd advocate using an anti-corrosion paste between the SS fitting and the mast. If you use tape, its likely to still allow salt spray to get between it and the alloy.

In any case, you must do a very good job cleaning up any corrosion before you re-install the fitting. Its also a good idea to apply a good anti-corrosion primer paint to the freshly cleaned alloy before you put the fitting back on. I'd use Monel rivets rather than s.s.

[nuku34]

BTW, do NOT use silicone! A no-no around alloy. If you want to use some sort of "goop" between the fitting and mast, use Sikaflex 5200 and do a good job of completely filing the space between fitting and mast, Use masking tape on mast and fitting so you won't worry about squeeze out of the goop.

[s/v Jedi]

I recommend to use Boatlife Lifecaulk and Monel rivets. Use Tef gel at the fasteners.

[Manateeman]

It’s difficult to see how much corrosion but I’d clean it up and post another photo.
You might want to consider an external wrap of one or two pieces in aluminum that is larger than the area. Then you could rivet it in place set in 5200.
I’m concerned about where this corrosion occurs.
Mark

[Manateeman]

Hi. I forgot to ask. Is the bolt free? I see you have the nut off one side. Is there a compression sleeve around the bolt or do the plates serve that function.
Do you know the spar builder. What are the dimensions please.
Mark

[DeValency]

Originally Posted by nuku34

BTW, do NOT use silicone! A no-no around alloy. If you want to use some sort of "goop" between the fitting and mast, use Sikaflex 5200 and do a good job of completely filing the space between fitting and mast, Use masking tape on mast and fitting so you won't worry about squeeze out of the goop.

+1 on these recommendations, clean really well, prime and paint first with designated aluminum paints, use monel rivets only.

And 5200 coat will definitely strengthen your mast for many years

[JeremyFowler]

Thanks for the recommendation! I should be able to get onto it soon - recovering from a hospital bout after the first Pfizer shot. Chhers.