Making your own (large) canvas...
Unless I paint smaller sizes, I build my own canvases using a piece of plywood nailed and glued to
a self-made frame (Home Depot) with masonite reinforced corners. All
the parts are nailed and glued together (Carpenter glue) - The glue is
essential. I use roll canvas from Dick Blick. It is quite a production
but at least my canvas won’t warp and I could go up to 4’ x 8’.
A few pictures will illustrate the whole (easy) process.