Regarding the query on melting wax in water.  Bee aware that water added to
wax saponifies, i.e. goes soapy, and cannot be retrieved.  The only water
that should be used is rain water or distilled water and even then I would
not recommend boiling the two together.  See my other comment the water
boils easier than the wax consequently an explosive mixture as you found.
Hence the fire.
 
I have melted wax in a steam wax melter and also in double boilers (one old
saucepan in the top of another).  This is by far the best method.
 
Barbara Dalby   England