I have just started using a new product called Frederix Archival Canvas Board which I like. Now I can start a painting without taking the time to make my own panel. I was able to get a 12 pack at Jerry's Artarama for a fairly good price.
Although when I frist started painting I used stretched canvas, all my current paintings are painted on canvas-masonite panels that I make myself.
My first problem was cutting the masonite. At first I used my husband's power saw, but, not only am I afraid of power tools, but I never cut it straight anyway. I finally solved the problem by cutting the masonite in a similar way to how I cut mat board.
Mark out the size of the panel you want in pencil on BOTH sides of the masonite. Make it 1/16 less than the actual size because you will be putting on canvas.
Put the masonite on a table with the edge of the masonite sticking out over the edge of the table
Clamp a stainless steel edge which is long enough to go across the entire width of the masonite (which is about 24") to both the table and the masonite.
Using a box cutter with a FRESH razor blade, lightly score the pencil lines about 20 or 30 times. BE CAREFUL TO KEEP YOUR FINGERS AWAY FROM THE BLADE. Turn the masonite over and score the back the same way. Usually this will get you all the way through the masonite. If you want an 18 by 24 panel, you don't have to trim any more. If you are making a 16 x 20, do the same thing as above for the width of the panel
Cut out a piece of UNPRIMED canvas at least 1 inch bigger on all sides than the panel you are making.
For an adhesive, I've always use Acrylic Gel. This makes a very strong bond and is compatible with alkyds. I use a wide paint brush and brush the gel over the entire panel. I smooth out the piece of canvas I just cut out making sure that there are no wrinkles. I turn the entire panel over and paste down the edges to the back of the panel.
I use Acrylic gesso to prime the canvas. Make sure to let this dry at least 24 hours. Otherwise, some of the water from the gesso might get into the paint.