What Grade of Aluminum for Masthead Arm?

[Patrick_DeepPlaya]

I want to use a 3" wide piece of Aluminum flat bar to install a Maretron WSO100 on my masthead. The reason for the 3" width is it would allow me to drill through and use the WSO100's three screws for attaching to the bar and it won't impinge on the humidity sensor which sticks out slightly from the bottom.

Are any of these grades available at Online Metals acceptable?

• 2024-T351 ALUMINUM RECTANGLE BAR
• 2024-T4 ALUMINUM RECTANGLE BAR
• 6061-T6 ALUMINUM RECTANGLE BAR
• 7075-T6/T651 COLD FINISH ALUMINUM RECTANGLE BAR

In terms of thickness, what is available differs by the type of Aluminum. I have a piece of 2' piece of 1/4"x2" here that seems stout enough, it's just not wide enough to get good purchase on the WSO100 so I'm planning on going with 1/4" or 3/8" depending on the material. If anyone feels strongly about the thickness please chime in on that as well.

Thanks!

[hellosailor]

Patrick, I'd think whichever alloy has the greatest resistance to salt corrosion is the one you'd be looking for. But at the same time...if you have a local plexi supplier, how about a piece of 3/8" or 1/2" plexi or lexan? Should be locally available, won't corrode or need paint, and if you're lucky they'll have a piece available in white, if you'd prefer. Better cheaper faster?

[GordMay]

Any of the Heat treated "T6" alloys.
6061-T6 is what your mast is probably made of.

[Weyalan]

I'd choose the 6061... it is very commonly used by the builders of commercial aluminium vessels.

[delmarrey]

5052 or 5056 is commonly use in the marine industry for hull construction (corrosion resistant) but the top of a mast 6061 T6 would be stronger.

2024 is for extrusions (moldings-soft) and 7075 is a hi-grade aircraft material.

[Patrick_DeepPlaya]

Thanks everyone for the tech info, exactly what I needed!

Lucky for me, Online Metals is right here in Seattle, WA and they have will call pickups!

-p