Mast fittings.

Ian_Rob

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Is there any reason why non-anodised aluminium washers shouldn’t be used as spacers for mast fittings? The mast is anodised and the fixings through the spacers would be Monel pop-rivets. The spacers would have mastic around them.
 
I don't understand what function this spacer is achieving.

It‘s to fill a 3mm gap between the feet of a radar mount and the mast to which it is to be pop-riveted:

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There would be one under each foot. The mating surfaces of the feet and mast have different radiuses so the spacers would also absorb the different curvatures.
 

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I think I'd be inclined to use nylon wahers.

That‘s interesting- thank you.

I have been investigating Acetyl (Delrin) and produced an STL file [the image above is from this) hoping that I can find a firm who could CNC them for me. To get the size and profile right I have been using the same file to 3D print PLA prototypes which led me onto looking at whether I can have have them 3D printed in Acetyl. Unfortunately, Acetyl is a difficult filament to work with and so far I haven’t been able to find a firm who can do it. I have been offered PA12 Nylon as an alternative but I am a concerned about its UV stability and the fact that it absorbs water - potentially affecting its size. Not sure whether I am worrying unnecessarily?
 

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One point on the diagram, it shows the lower bolts pointing upwards, I would always put them in pointing down if I can, so that they stay in place if the nut comes off. Even with nylocs.
The photo actually shows the mount upside down as it was easier to set up in that configuration but it is a v. good point re the bolts which I hadn't thought about.
 
I liked a simple suggestion read recently on here involving thickened epoxy in the cut-off finger of a glove (or a similar flexi receptacle) that is squished to take up the exact shape, allowed to cure, removed from the glove and used as the spacer.

I was planning this with our Scanstrut (relocating from stern pole to mast), but on closer inspection ours is only a couple of mm off the mast profile at its worst point so a dab of polyurethane should do.
 
I liked a simple suggestion read recently on here involving thickened epoxy in the cut-off finger of a glove (or a similar flexi receptacle) that is squished to take up the exact shape, allowed to cure, removed from the glove and used as the spacer.

Yes, it was an ingenious solution.
 
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