To avoid a mess just buy the CWF(clear wood finish)available anywhere, The stuff is designed for decks.Do all sides well before assembly, you can mop on a coat every year, right over the bed strips and bolts.If you want dark boards stain them first.Its not a easy scratched finsh tratment but soaks into the wood.Oak is a superior bed wood material, reasonably priced and grown right here in the USA and will last 25 years if treated once a year.