Welcome to SEMicro!
Our gaskets are made of an RTV material that is fairly resistant to abuse. However, should your gasket become chipped on the outer diameter or torn it should be replaced immediately.
Note that in most cases you may service your piston/gasket yourself. You may want to do so if you notice that the piston pressure no longer increases in a smooth manner but is rather jerky. To service, remove the gasket from the piston, clean it with soap and water, place in a ziplock bag with a small amount of talcum powder and shake the bag. Your gasket is now clean and lubricated, ready to provide you with smooth, controlled adhesion tests.
If you are using our F-20 piston, you may wish to purchase only the F-8 or F-12 gasket if only one needs replacing. To replace both gaskets, choose 'F-20' from the drop-down menu above (you will be charged for 2 gaskets in this case as shown when selecting 'F-20').