Oak is a unique wood when it come to the use of stain. If you sand Oak to smooth it will not accept the stain. I normally stop at 150 grit when staining Oak. You may have to let the stain soak in longer than what it says on the can of stain, but don't let it dry. I usually keep the oak boards wet by adding the 2nd and 3rd coats before wiping off the excess. Again you may have to apply stain the next day to get the color you want. I use WATCO Danish Oil to stain my oak, comes in a few colors. Check Lowes, they carry it. The Danish oil will soak in the wood more so than stain. It will leave a hard coat finish, but you still must topcoat it. Helmsman Spar Urethane is what I found the best to use on wood exposed to weather. I used 7 coats on all sides and ends of the boards, sanding lightly between coats to get that nice smooth finish. Check out my cherry wood, purpleheart bed on the web site below. Any more questions, please ask!!!!!!!!!!!
Coach Frank