I have a leaky faucet in the tub I replaced the cold water valve and need to replace the hot water valve,I am using the shower valve socket wrench,the hot water valve is on so tight that I have stripped three sockets.I have tried turning the water off over night and put some penetrating oil on the back of the valve to try and loosen it up but nothings working?

Yes, indeed, aluminum socket will "strip" easily. If you have part of the stem body sticking out from the wall, take large Channel Locks and loosen stem directly. Or, go to Auto Parts store and buy deep socket to fit the stem. These sockets are well build. Also, you will have the luxury of using ratchet that will give you more leverage. It will cost you few bucks but will accomplish what you want to do.