does anyone have any experience with world war 2 bunkers what should i use ive got this idea of using plaster of paris is there any other alternatives!

Heck, yes! Build your basic out of styrofoam (packing foam) and then cover it with drywall compound (joint compound). Here's a link to a fellow that has done what you would like to: http://members1.chello.nl/~jm.albers/projectse.htm

thanks mike that seems to be a very good idea!

Here's a trick for using the drywall compound. Mix in some acrylic paint the same colour as object your applying it to. That way the colour goes all the way through and chips or nicks won't show white. It also cuts down on painting. If you apply just the right amount of paint in the first place, you might not have to do any finish painting. Just drybrush and weather.

Better still...Use the KFmagee' s Balsa Foam, it 'll be lighter than plaster of Paris...!