How would i make a set of sandbags that i could stack up and secure together to make a foxhole or a small barrier?
Self hardening clay or sculpy. Roll it out, flatten to shape cut to size, reshape and stack. Get the arrangement right disassemble, then follow the instructions to harden. Once that is done reassemble.
Just to add to Gerald’s post, you can use an old cotton t-shirt to press the texture to the clay.
I just build them (w/Sculpy) on a piece of foil on a cookie sheet and bake them in place…