When I bought my first second-hand foil, it came with a 1 or 2mm rubber "gasket" (just a piece of rubber cut to the same size as the mast plate with holes that match the screw holes of the plate).
When I upgraded my foil kit (also second-hand kit) I went to the hardware store and made my own gasket. I have had one occurrence where the middle screw in the mast plate to fuselage has come loose and has rubbed and marked the gasket and without the rubber would have marked the board.
As I have never bought a new foil do they come with a "gasket" thingie?
Do you make your own or not use anything?
Thanks.

Made something very simple sound very complicated and stuffed up what I was talking about.
From the top, it goes
board
rubber gasket
mast plate
mast

Do you use something like this?

Mines metal plate to board. Rubber gasket is going to allow for movement as the rubber compresses under loading. I want connections as rigid as possible. JMO

Henners said..
When I bought my first second-hand foil, it came with a 1 or 2mm rubber "gasket" (just a piece of rubber cut to the same size as the mast plate with holes that match the screw holes of the plate).
When I upgraded my foil kit (also second-hand kit) I went to the hardware store and made my own gasket. I have had one occurrence where the middle screw in the mast plate to fuselage has come loose and has rubbed and marked the gasket and without the rubber would have marked the board.
As I have never bought a new foil do they come with a "gasket" thingie?
Do you make your own or not use anything?
Thanks.

I'd be more concerned about any screw working loose. I've seen it recommended elsewhere and would concur that Tef-Gel, besides its corrosion protection, inhibits screws from working loose.

Can't say for all makes but my NP foil did but has holes in the gasket for the screws connecting the plate to the mast. I would imagine many aluminum ones do as it makes assembly easy as the gasket is glued to the plate. The situation may be different for carbon fiber foils with integrated head plates.

When I used the slingshot mast (with a lip around the mast head) I didn't put anything. If I were you, I would use a very hard and thin rubber or plastic shim. The other option would be a very soft (and thin) shim so it can get compressed easily. Otherwise you might run the risk that mere use will compress the shim and the screws can get loose.

no real need. I get some scratches from sliding the foil mast around, but i think you would get those with a gasket anyways. You are likely to do much more damage to the nose of your board with your mast than your foil will do to the bottom of your board

Axis come with a rubber gasket fitted standard to the mast plate. Works really well and I think it does a lot of good for the board in terms of protection.