I'm installing a mantel that I ripped out of old [ 4 yrs ] Doug Fir logs. They are rough and will have the wayne of the log facing the room. Their dimensions are 6x10. My question is about staining. If I use a sanding sealer, should I also linseed oil the end grains? We're planning on a natural stain. Another concern is heat and it's long term affects on the finish. I will not have access to commercial products. Just Verathane,Minwax and the like.