TrekboxX
Supporting Vendor
Trust me, I understand the need to fulfill every need/eventuality, I'm famous for over thinking stuff. But I've come to realize it's better to do it one way, and do it well. Decide how you'll normally use the top and design it for that.
The HDPE is pretty good stuff. Easy to machine, but I doubt anything will stick to it (epoxy, etc.). It's not incredibly rigid, so for your application I'd go with 1/2 or better, and that can get somewhat heavy. There are better materials IMHO, and I'm actually incorporating one into my new design, but they are expensive, hard to machine, and a total PIA to obtain in anything less than a truckload. You'll probably be done before I have any, but if not I'd be happy to send you some. Pm me if you like.
edit- if you go with HDPE, get Starboard. It's textured HDPE with pigment added and much more UV stable, if I understand correctly.
The HDPE is pretty good stuff. Easy to machine, but I doubt anything will stick to it (epoxy, etc.). It's not incredibly rigid, so for your application I'd go with 1/2 or better, and that can get somewhat heavy. There are better materials IMHO, and I'm actually incorporating one into my new design, but they are expensive, hard to machine, and a total PIA to obtain in anything less than a truckload. You'll probably be done before I have any, but if not I'd be happy to send you some. Pm me if you like.
edit- if you go with HDPE, get Starboard. It's textured HDPE with pigment added and much more UV stable, if I understand correctly.