That works to, I think.
I would go for the fiberglass build up as suggested by Will. Strong. Easy to mold and work up. It will bond to the existing material. While HDPE feels attractive the lack of bonding ability limits some of it's use. Even for backing board they have identified G10 or even fiberglass over plywood to be better as backing board then HDPE.
I would go for the fiberglass build up as suggested by Will. Strong. Easy to mold and work up. It will bond to the existing material. While HDPE feels attractive the lack of bonding ability limits some of it's use. Even for backing board they have identified G10 or even fiberglass over plywood to be better as backing board then HDPE.