well it takes a lot really drift wood has drifted in the ocean for a long time before comming to rest on the beach. trying to make it wouldnt work the same as free floating in the ocean. not sure exactly what it does to the wood but soaking it in water for a long period of time will just rot it. the soaking part your seeing is to get all the brown and particulate matter off the wood. as it has completely dried out before we get it once it goes into water again it will absorb the water and turn the water a muddy brown.
I say if you want drift wood its better to buy unless you have a beach close to you that it washes up on.
Mike