With lots of money........no really.....You take a piece of clean gear, the higher the better, clean means no stats on it originally, then you place it in your transmuter with a purified fusion stone (19 diamonds + one transmuter charge). This provides you with one clean tier stone, probably tier 4 (depends on the tier level of teh gear). Great now you have a clean T4 stone. Do this three times and place all three in teh transmuter, this gives you a clean T5 stone. There T5's gives you a T6 and so on. By teh time you get to T9 you will have used 729 puries and 734 transmuter charges (and consequently spent about 14,000 diamonds).
And yes, adding three T9 stones to whatever tier weapon be it T1 or T11 will make it T9.
Obviously this is not the way to go.
... 
