Leather Cups, water pumps

[frankss]

Hi;

are there recommendations for the best leather for piston cups,

as well as how to form same ?

Thanks frank

[Kevin]

I would use a piece of vegetable tanned leather because it can be molded and hold the shape after it dries. Make a male and female mold and use a clamp to apply the pressure and leave it alone until it is dry. The hard part for me is leaving it alone, I have to check and see how it's doing every five minutes.

Good luck,

Kevin

[UKRay]

I would use a nice clean piece of veg tan belly whatever thickness you need to go over the metal washer on your piston and make a sensible seal. The last one I made was for an old brass 1.5" bore boat bilge pump. It worked for three or four years and was still working when I sold the boat so I guess I did something right.

I simply got a bit of wood and carved it to the same size as the washer and pulled the water soaked leather down hard over it to make the cup shape. I tacked it down and left it a couple of days to dry out before cutting to size, greasing it with whatever grease I had handy, punching a small hole for the retaining screw/bolt whatever and them fitting to the boat pump. Having primed the pump it took a day or so for the leather to swell back up again (or whatever it did...) and the pump to work properly again.

I don't know if this is the right way or not but it worked for me.

Ray