Whats the best fitting for items going on a new mast

[FionaJC]

I am being supplied a new mizzen mast for me to fit various items and then its being stepped for me later.

What are the best fittings to use? Aluminium rivets, stainless self taps (don't like the ide of fraying halyards so Ill blunt them), Monel rivets, Wrigley's gum - no seriously! I want to minimise corrosion as I had a radar head falloff one year.

I am fitting: VHF masthead antenna, USB WiFi antenna, TV/FM Triax UFO, LED Deck light, SW active antenna, NASA Navtex, NASA LED anchor light.

(NASA is a UK based marine equipment manufacturer, they have an arrangement with NASA USA, they each stick to their own and NASA UK doesn't do space exploration).

[sailingharry]

Our mast, made by Offshore Spars, has several items attached with machine screws. It is now 20 years old, and I have had some screws that I have been able to remove. But then again, I have a 4-year-old outboard where machine screws have permanently bonded to fittings.

I can suggest these.
https://www.grainger.com/product/GRA...Shoulder-4DCP7
I first saw these on my Watt&Sea, they do a very effective job of insulating aluminum from stainless. I just used several of them to mount aluminum framing to my stainless steel arch to hold up solar panels. Absolutely zero dissimilar contact. Not entirely sure how well they would work for your mast mounting, is they are most ideal where you have a through bolt arrangement with a nut on the other side.

There is the longstanding recommendation to put some agent on the threads. Lanocote, Tough Gel, or the cheap but effective alternative of Blue Loctite.

[Matt Johnson]

Monel and Tef-gel works great. If you can put a hard plastic sheeting under the fitting as a gasket, that helps too. Just don't use anything porous that can hold moisture against the aluminum.

Matt

[Manateeman]

TIG weld a plate pre drilled and tapped. Tef-Gel the bolt threads. We like big monel pop rivets. As stated above, keep the water out.
Even the black plastic degrades in the sun. Not big on plastic or rubber. Lots of other gasket materials will work with 5200.
You can always have stuff done with Cera-Kote.
Experimental aircraft guys have interesting solutions.
Happy trails.
Mark and the manatee crew.

[Benz]

Drill and tap threads for SS machine bolts. Use tef-gel. If worried about rattling out, use loctite.

[Patrigo]

Rivnuts! Rivnuts, and use suitable insulation/sealant. They cannot pull out or come undone on their own.
Patrigo.