If you've ever framed a lot of artwork, you know how quickly the expense can add up! I build my own frames to save big time. I begin with small backing boards so that I will have a surface to nail quarter inch thick slats around the artwork. Thanks goodness for power screw drivers!
I use elmer's glue to hold the masonite panels on the backing boards.
And a few small wire brads to hold the panels in place while the glue dries.
Below the slats are in place making a simple frame.