Primed panels are much less resistant to my painting knife and allow it to glide over the surface of the painting. Gesso creates more of a dry absorbent surface to paint on.
I can make just under 40, 9 x 12 inch panels from a 4 x 8 foot 1/8 inch thick piece of Masonite panel. It is the panel that has the screen like texture on the backside.
I go to Home Depot for my purchase since they will cut the 8-foot panel into 4, 12-inch long sections. Then cut them in half long ways so that they easily fit in my car for transporting to my studio. In my garage I cut the long sections to 9 inches wide with my table saw. This will provide me with a nice 9 x 12 inch panel, ideal for plein air painting.
I lay them all out at one time and a few folding tables and begin priming them. I find that using Kilz Latex Primer works well for me. I let this first coat dry completely. Then the next day or hours later apply a second coat. No matter how thick I paint on the primer, within reason, it will dry almost completely flat.
Two coats seem to be all that I require. I would add a third coat of primmer if I applied it too thinly and could see the original panel through the primmer.
When completely dry I sand the sides of the panel with a sanding block to get rid of rough edges and primer spill over.
Preparing this many panels at one time makes it nice. I will have a supply for several months. Lets compare price; 40 panels for $9.00 or 40 canvases for over $300, food for thought. Okay we thought long enough.
Hope this helps. Questions? Email me at contact@DarylUrig.com
For a beginners Guide to Plein Air Painting purchase my book:
Plein Air Painting for Everyone
http://www.lulu.com/spotlight/Plein_Air
I do the same but I have the HD people cut the panels all the way to the desired size. They have been always happy to do this. All I have to do is bring them home and prime.
They make allowances for blade thickness. I have them cut the masonite into 12 inch strips then they cut them on the cross cut saw to the desired length. Price is perfect and sames tons of time.