I am trying to produce a rigid "jello mold" object, a donut sliced through. OD of 6-8 in./ ID 3-4 in.. My concern is the thinning of the material for the interior hole. Can this be over come? I would plan to use .063 - .094 PVC or ABS, I would open to any suggestions, can not be too heavy and must be rigid. Thanx