Aluminum Mast & Stainless Deck Plate

[mike_hancock]

I am about to put a stainless deck plate under my aluminum mast. Any ideas how to isolate the aluminum from the stainless? Almost anything I can think of will crush under the weight of the mast.

Thanks,

Mike

[David M]

Mike,
For your application, check out the characteristics of Delrin 150 plastic. I use it under a couple cable winches where the bolts are torqued down quite a bit. It is very resistant to deforming under compression. It doesn't really deform at all. Purchase a relatively thick piece that is better able to distribute the load evenly. I think you will be happy with it.

[Cheechako]

It's hard to say without knowing the configuration... you mean just a flat plate? or does it slip inside the mast base...? If the mating surfaces are flat you could just put a thin sheet of anything from nylon to hpmw or whatever to isolate it. thin sheet material is available through Mcmaster Carr. They give a good explanation of UV resistance and strength too. In compression, I dont think you have any issue with crushing strength though...
If it's a painted mast, you may be asking for trouble though. Is there a reason you are putting stainless there?

[David M]

I don't think you want to use any sort of soft or brittle plastic for this application.

[GordMay]

Why not put an aluminum deck plate under your aluminum mast?

[Rex Delay]

If you know anyone in construction, there is a commonly used material for bridge bearings, black rubbery material, forgot the name of it. The stuff is very strong and perfect for you application. Used it many times myself but the name escapes me.

[imagine2frolic]

Imagine has some sort of plastic shoe that fits the bottom of the mast, and the stainless plate for blocks under that......i2f

[Rex Delay]

It is a high density Neoprene bearing pad. Comes in varying thickness and would be perfect for both bearing and isolation pruposes. The size you need would probably be free scrap from any construction outfit that does bridges (large or small).

[mike_hancock]

Thanks for all the suggestions. The mast will rest on the stainless plate. The real reason for using the stainless plate is that it fits - none of the aluminum plates that I found were suitable.

Mike

[Extemporaneous]

I have a similar setup. It's a flat SS plate welded to the top of my compression post. The post then slides through a hole in the deck (plate stays above the deck) and then down into a sleeve which is welded to a shoe/saddle in the bilge on top of the keel. The aluminum mast deck plate/shoe bolts on to of the flat SS plate.
I was just going to coat/paint a couple of coats of epoxy on both of the surfaces.

Would this not work?

Extemp.

[GordMay]

Originally Posted by Rex Delay

It is a high density Neoprene bearing pad. Comes in varying thickness and would be perfect for both bearing and isolation pruposes. The size you need would probably be free scrap from any construction outfit that does bridges (large or small).

Bridge bearing pads are generally meant to accommodate flat (horizontal) plate-to-plate connections, so a hollow vertical mast would require a closure plate (shim) on it’s bottom opening surface. Left hollow, the mast’s vertical edges would cut into the elastomeric isolator.