I am extending the front deck on my tracker and was wondering what I should use to seal the wood.  I was thinking thompsons or something like that.  Thanks for the input.

Most guys use epoxy resin.  Tough stuff and made to last.  

I used outdoor grade paint, like you would use to paint your house.  I haven't seal a whole deck however, and maybe paint isn't good enough.  Maybe someone can help us understand why epoxy resin is the right stuff compared to paint or Thompsons.

Thompson's works extremely well. Epoxy works better but you get to deal with the mess. Whatever you do, liquified wolminizer will eat aluminum at a fairly quick pace, so don't get wolminized wood or aftermarket wolminizer.