Sintra is PVC foam board. A 1/4" Sintra weighs less than 1/8" ABS. Sintra is carried by sign and plastic suppliers try to find one local to avoid shipping fees. A 4'x8' piece of Sintra cost me $100. It has a very fine almost smooth texture on both sides. I have used ABS in the past it works, but the Sintra works and looks better. It is stiffer than the ABS and you can sand the edges round with regular wood type sand paper.

 

looks good well done