Home Anodeiseing

Here iam trying to anodeise the jack shaft, its in a bath of sulphuric acide with 12v being past through it, forming hydrogen at the lead cathode and oxygen at the aluminum anode wich combines with the aluminum to form aluminum oxide, accept it didnt as when i put it in the dye tank it picked up no colour , The reason i now sumise is that the acid was way to dilute,
Ive got some stronger now and will try again.