Hi im trying to build an Israeli dio depicting a Merkava mk3 patrolling the separation wall. I want to use a plastic tube for the watch tower bur would like some tips for applying the best concrete effect over it. I am also using thin plywood for the wall and would like to use the same technique for this too. Thanks Andy

A couple of ideas pop to my mind.
1. House hold spackle/wall putty may work - depends on how smooth you want it.
2. There are textured spary paint cans here in the US. They are a combo paint and course texture. The color wouldn't be a show stopper because you could paint over it.
3. A sheet of sandpaper cut and glued and painted may work too - provided you can find the right grit/grain.

Thanks
Would the spackle / paint adhere to the plastic ok?

I would roughen the plastic and mix in some white glue