Be advised that if you sand pressure treated wood that you will be producing some pretty nasty sawdust. It might not even be legal, I don't know. You would need to take great care to make sure that you don't breath it in, that it doesn't get breathed or injested by children, especially and that it is disposed of in a safe and legal manner. Also, the rental shop may prohibit this practice and you would need to be sure that the dust bag and all of the equipment was clean and free of poisonous dust. This wood can contain arsenic or other toxins.