[sthom21]

I couldn't tell from this post if you ever used a drum sander so I would like to put in my two cents just in case. If you have never used a drum sander with 36 grit, I suggest trying it on a couple pieces of old decking or a piece of plywood before using it on a customers deck. 36 grit will take alot of wood very quickly if you are not careful. It is very easy to leave divots and end up with an uneven surface. Practice is key to getting a smooth surface with a drum sander. Even 80 grit can get away from you if you haven't done it before. The processes mentioned above are definitely the right way to go, but be very careful as it is easy to take alot more wood than you may think are taking.
A possible alternative: It will take quite a bit more time, but if you have a belt sander, it would be alot easier to contol than a big drum floor sander, and alot easier to fix any problem. Good Luck!!