But it can be made independently. Just take a piece of sheet rubber with a thickness of 3 mm. And do not groan that it is also not at hand. Rubber of medium hardness can be found in any house. It can be car rubber, and the sole of old shoes, etc.P. Since the laying itself has small sizes, you will need a piece of rubber not large.
Lay a strip of rubber on a wooden plank, and on top – a gasket extracted from the tap. Using a sharp knife, cut the part of the desired diameter out of rubber. Then, with the help of a special survey (metal tube) with a suitable cross section of the internal diameter of the gasket, a ring of the desired size is stamped. So that the surplus is acute enough, the end of the tube should be sharpened on a grinding circle or using a file.
You can go in the other way – put the gasket blank in the valve and only then pierce the hole in it with a nail. Then the valve with the gasket should be put on a spindle centering ledge, previously lubricated with machine oil, cream or household soap.