When I first started painting on wood I was out of work and simply sitting around waiting for rejection letters. I took my last spare money and priced out some material to work on so as to put my time to something more constructive than worry. I found that Masonite was quite a bit cheaper than canvas. So I bought a sheet and had it cut down. I bought some wood, borrowed a friend’s chop saw and started building cradles to support the Masonite.
Over the years I have studied and refined my techniques. I now use birch plywood as I wrote in a previous post and my panels are lighter and stronger than ever. At the outset, there wasn’t a lot of information published on how to create a good panel. I got most of my information from an antique book which I have since lost, but the internet is now rife with different advice and styles of construction. I’m not the best woodworker in the world by any means, but I have gotten pretty good at lap joints. They’re simple and a lot stronger then a mitre corner. People like the mitre because it’s hidden – but sanded down and painted over, any joint is almost (if not totally) invisible.
I cut half laps for the corners with poplar finish wood. Poplar is fairly light, strong and inexpensive. It’s sometimes hard to find good straight pieces and I occasionally have to visit more than one store to obtain a good stock.
I then cut laps for the center pieces. For 1/4″ plywood I don’t like to have the supports more than about a foot apart.
For gluing, I used to use Gorilla Glue, which is a urethane glue. It is fantastic if you have gaps to fill between pieces, but for this kind of work I now prefer Tite Bond. I read an article in Fine Woodworking Magazine (which is only available to subscribers) on the strongest wood glues. They tested the market leaders using a bridle joint which they then stressed to the breaking point. Tite Bond came out way ahead. I finish construction by gluing one inch deep feet to the inside of the cradle so that when the finished painting is hung, it will appear to float about half an inch off the wall.
Once the glue is dry and cured for at least 24 hours and the clamps come off, I coat the entire panel with whatever ground I am using for the medium of choice. It’s good to coat the back as well as the front to prevent the wood from breathing unevenly. For acrylic I use either white or black acrylic gesso — at least four coats. For oils I use Gamblin Ground — at least two coats. Gamblin Ground is amazingly white, tough and if you want to sand it, it can be made as smooth as the finish on a car. There’s an excellent video of how to apply it on Gamblin’s site. Also, those promotional credit cards I get in the mail all the time make excellent trowels to spread it on with.
In the olden days they recommend not touching paint to wood until the cut, uncradled wood had aged in your barn at least 10 years. Modern materials are a lot better than classical ones and, though wood itself hasn’t changed, most of us can’t afford to keep a back stock for that long. Also, I do not have a barn.