From cake to crater

When playing miniature wargames I have found out that one
thing to get the right gritty and worn down feeling you need
the right type of scenery. Ruins are under construction but
I have never tried to make craters. My wife is a very skilled
woman and has a former career in the cake and pastery-
profession and from time to time I am invited to taste her
masterpieces. :) Not so long ago I ate some of her muffins
and cupcakes and after this lovely experience I sat down
with the leftovers and discovered that the aluminium-forms
would be a good frame to build up a crater from a grenade-shell.
I use the small craters for 100kg bombs and the big for 250kg
bombs. The pictures show the stages when making the craters
and I start with two plain layers of pva and after that
another two with mixed pva and sand.
To chamfer the space and the sharp edges in the ridge of the
big bombcrater I have use polystyrene as a base under the
layers of pva and sand.  
Last and final stage in this process will be the lick of paint
and shading(next report). I will also use som black in the
paintjob to symbolize burn out and dirt after an direct hit.