Need Advise on Building Large Arch Gate
I am trying to make a large arch-like gate out of foam. It would be about 8' high, it would have to stand on its own, it would have to be able to be broken apart into pieces and needs to be able to last in the elements. I was thinking of buying wet foam blocks (foam used by florists) and binding sets of them together and using spray foam to cover the outsides and paint it grey to make it look like rocks. It would be held together with dowels through each set of foam and have an anchor at the bottom using dowels hammered into the ground.
Inspiration for this design came from the vault from the Borderlands game series
I wanted to know if anyone has seen guides for making a fake stone arch or if anyone had ideas for making this (Especially if the ideas aren't too expensive)