intresting line of discussion . I run 800 odd hives ,two years ago i made up
200  supers from pinus radiata  , this was soft fast growth sap wood ,not
heart wood ,as its much cheaper. i dipped  and painted about 70 of them,
just dipped another 80 and put out the rest in their bare state. I'm just
starting to catch up on my maintenance now and have found the dipped and
painted boxs are in as new condition,
    the just dipped boxs are still sound but the outside surfaces have
become quite weathered and look scruffy redipping and painting when still
hot with water based paint brings them back to new look.( i think the paint
acts as a sun block and stops uv damage to the surface layer)
    the undipped boxs are full of rot and are falling to pieces,the ones
with a little rot spot can be dipped and painted the rot goes hard in the
wax which seals out the air and moisture  which fungus needs to grow and the
heat of the wax kills the fungus spores in the wood theseboxs will last
another 5 or so years.
     i live in a very humid wet warm climate during the sping and early
summer we then have a dry late summer autumn with a wet cold winter ,
moisture is with us most of the time and the only way to seal all the end
grain in a box is to dip it in parafin. I dip all my lids, bases, split
boards(these foam a bit) queen excluders (cleans them up a treat and
prevents rusting) and feeders.

    Shaun Cranfield
 Auckland new zealand