There was work published by Kalnins and Detroy in the late 70's in the
American Bee Journal ( I think) that showed paraffin wax was not very
successful as a preservative.
 
Here in Australia, there have been beekeepers who have used paraffin wax for
preserving bee boxes but they did not last more than 4 or 5 years.  There are
several factors to look at when it comes to judging how long something can
preserve a bee box for.
 
Firstly, there is the natural decay hazard existing in your area.  If it is
not high, then even untreated timber will last a long time.
 
Secondly, there is the natural durability of the timber being used.  Here in
Australia, natural occuring hoop pine used to be used for bee boxes.  This has
a lot higher natural durability that the plantation grown hoop pine which is
the most common timber used nowadays.  There is also plantation grown radiata
pine which has a very low natural durability.
 
I have been told by beekeepers who visited New Zealand many years ago that the
beekeepers were first treating their boxes with copper naphthenate before
treating with paraffin wax.  This is why the wax solution was green.  There
has been an article published in Australia that says that boxes treated with
copper naphthenate should not be hot wax dipped in paraffin.  It is something
to do with the volatiles produce by heating the copper naphthenate.
 
In summary, our experience here in Australia is that in high decay hazard
areas, hot wax dipping of boxes with paraffin wax does not extent the life of
the box very much.
 
Trevor Weatherhead
AUSTRALIA