[woodnthings]

Actually, wood is not very durable unless maintained well. I would consider Lexan, or Plexi-glass or steel. The metal would require a water jet or laser cutting. Theplastic you can do on your CNC. You can combine materials as well.
Trex is another plastic material used for decks that will hold up well in all types of weather. The boards can be trimmed so they butt together without the "V" grooves for a flat surface.

 

[woodnthings]

I've got a bunch of 8' Trex boards off the old deck

Wondering how I could make a panel. Mount to angle iron? I researched glues that work on Trex a while back and couldn't come up with anything surefire.

Thank you WNT.

To make a panel, trim off the tongue and groove joints to a get a flat edge or use a 1/2 lap joint so there's smooth surface without any small grooves.
A waterproof adhesive like Liquid Nails will hold them together if you want both sides visible and no fasteners showing. An angle iron frame or wood frame will also work.
The real question is what paint will adhere to the plastic surface? A call to Trex may help?
My Trex boards are two colors, red on one side and black on the other.