I use free broken foam boards or scrap , that I get free from jod sites

After I rough cut the pieces , I glue them togeather with glue designed for foam

After the glue drys I use a belt sander mounted to a bench to carve the blocks into decoy bodys ( out side )

I inlet a strip of pressure treated wood to atach the keel to later
I then burlap the foam bodies and add a Trex keel with SS screws

After I paint them I add a head that I buy

BTW if you use the right paint
It will not eat the foam

John