Summary

I wanted to use 3" by 1" Aluminum for my LED sign but that cost too much.
I had some 2.75" by 3/4" Plastic U channel and I used that instead.
The corners were 3D printed using PTEG for dtrength.
The LD panels were spaced back using 1/2 inch spacers.
This could be easily enlarged to work with 3: aluminum as well.