I don't have the lights anymore to check but I believe I used 1/8 inch acrylic on my 4 foot 8 bulb unit. I also used 4 stand offs per side (8 total), not just at the corners, so it was supported in the middle too. The stand offs are threaded for screws at both ends. I took out the bulbs and reflector, drilled small holes in the metal housing and used screws to attach the stand offs to edge of the unit. Then I put the acrylic on the stand offs and marked where holes should go, drilled the acrylic carefully and then used small screws to attach the acrylic to the stand offs.

Does the acrylic slide between the bottom of the stand off and head of the bottom screw?


thanks for the tip