yeah i just did mine with the clear plastic corner guard and small strips of weather stripping for the spacers. I painted it first. this is the shit! thanks.
Most home improvement stores will probably be your best bet and you can use light duty tin snips or heavy duty scissors.
I hate to be a buzz kill on an excellent DIY thread... but whenever I get in this mode, I have learned that I need to take a step make and see what is out there, because most likely, I'm trying to reinvent the wheel.
I did just that... and here's what I came up with:
http://www.adorama.com/DKL8.html
Pre-fabbed 8"x 8" darkroom vent... now for me, I'd rather save the time, effort, frustration, and mess of cutting and painting the DIY version... that, at the end of it all, doesn't have a mounting flange.
However, in the DIY's defense... it is very scalable... If I had to make something larger than an 8" x 8"... then this method starts to be a whole lot more cost effective.
Just my $.02! ...rock on...
how much would it affect the airflow if you put some breathable cloth of some sort over the outside of the vent to block the little amount of light thats getting in?
Its all good but I'm not convince that this block 100% the light!
How do you mount it on your cab?