Step 13: Filling and Sanding
Chances are you will have one or two nails that didn't go quite the whole way. Just get a fine screwdriver and place it on top of the nail and hammer it in very carefully, then continue filling as normal. Once you have all of the holes filled, let them dry for an hour or two or ten or however many it says on your package.
After everything has completely dried, you are ready to sand. Woo hoo! You can use whatever kind of sander you want, or you can strap a piece of sandpaper to a block of wood for all I care. Take the 220 grit sandpaper and put it on the sander of your choice. sand each surface smooth going back and forth with the grain of the wood, rather than side to side. You can also smooth out the corners slightly and the edges that meet up on the bevel. Unless you are a very good woodworker (and I'm sure some of you are), these edges will need a little refining. Don't get too ridiculous though, you still want to have nice crisp corners. Do this to each piece until you are satisfied with the finish. Make sure you sand the entire surface. The point is not to smooth it out (the planks are already pretty smooth from the initial planing phase these boards go through), but rather to roughen each surface to an equal texture, that stain or paint can be applied to it easily.
After you have sanded all of the pieces inside and out, you should probably go have a drink or something. Speaking of which, you should be doing this work outside or in a woodshop, but I hope you figured that out already.
The last step in this process is to clean clean clean each piece, making sure there aren't any stray particles or dust specks floating around. This can ruin your finish if it is not cleaned completely.