80mm Fan + Grid/Filter harness

I am building a sound dampening box for my Printrbot Plus with 2 fans for airflow.
I needed a a strong and tightly fitted harness to hold those 80mm fan and their grid/filter from the inside of the 10mm thick box.
The result is a tigh hold with the whole smoothly lined up with the outside wall.

80mm Fan: Arctic Cooling F8 Silent https://www.arctic.ac/eu_en/f8-silent.html
80mm Grid: SilverStone SST-FF81B http://silverstonetek.com/product.php?pid=269

Don't forget to use supports!
The scr