Objective: The objective of this article is to demonstrate attaching a Luan board (the plate) to a frame made of canvas stretcher bars then coating the plate with Gesso.  In the example used here the stretcher bars were purchased from Amazon and are low quality.  But since this is all about a board and not canvas, high quality stretcher bars are not necessary.

Oil painting on a Luan board is much easier than on a canvas.  On canvas, painting can become an exercise in frustration due to the rough surface of the canvas.  Also, Canvas is difficult to prep with Gesso and can easily rip if you attempt to scrape. A durable board can be made out of 1/4 inch Luan plywood mounted on  a  wood frame.  The process is simple, but it does take time.  However, there is a great sense of satisfaction in doing a painting on a board that you constructed. Construction of your own painting surface greatly enhances the opportunity for injecting yourself into the painting.  Make the boards only as you need them, that way each board becomes your personal craft rather than an assembly line of crap and the time used to construct the board gives you time for reflection on what you will paint.

Luan is not quite the same as normal plywood due to how it is made.  Normal plywood is literally layers of wood glued together with an external veneer.  Luan has an AIREX ® solid foam core with an external veneer glued to the core. It is much lighter than normal plywood.  A board made of normal 1/4 inch plywood, if warped, can bend the board’s frame.  Luan does not have the strength of normal plywood and will easily conform to the frame’s flat contours.

The real advantage to making a Luan  board is that it is so easy to scrape or paint over.  This saves money and you are not stuck with a painting taking up space.  With one board you can easily experiment with paint and when something does not work scrape it off, wash down with mineral spirits, lightly sand then spray over with a high grade oil based primer.   When done correctly this type of board is extremely durable and will not change shape as can happen with canvas on a frame.  Many problems occur with canvas because they are fragile and incur problems when moved around such as shipping.  A Luan board is so durable that it simply is not effected by movement.

The major hurdle in using Luan is that it has a mahogany veneer which has a rough open grain surface.  This surface grain has to be filled in order to have a smooth glass like surface.  The simplest method for closing the grain and achieving a smooth surface is by careful application of Gesso.  How the Gesso is applied makes a big difference in  the final result.  Essentially this comes down to understanding Gesso.  It is a goopy substance with properties that are designed to be used as a grain filler as well as a barrier between the wood and oil paint.  However, it must be applied in very thin layers and each layer must dry completely before applying the next layer .

There are two sides to the Luan board: the front side has mars, scars and other marks filled with wood filler and is somewhat smooth, the bottom side is rough and scars and are not filled. However the front side is not completely free of scars. The following picture is a very rough piece of Luan. The toothpicks are pointing out the tiny flaws on the front side.

 

 

Both Lowe’s and Home Depot will cut the size you need.  However, don’t expect perfection in the cut.  The saws used are for rough cutting and the precision of the measurement is not all that great: it can be off a bit.  Usually these stores will have a rack of 2 foot x 4 foot rough Luan half sheets. You can purchase highly finished and smooth Luan, but it can get expensive.  The rough Luan is very inexpensive (less than 7 dollars) and these half sheets  (24 inches x 48 inches) are usually seconds in that they have a lot of patches etc.  But these patches do not effect the utility of the board, since the board is eventually covered with Gesso. When the board is cut to your requested size make sure that it is cut with saw blade turning into the front side.  As the saw rips the material the edges shatter as the saw blade bursts though the plywood.  Tell the person cutting the board that you want the least amount of edge damage to the front side of the board.  These store blades are coarse and therefore there will be some damage to the edge of the front side but these are easily repaired.  Any major damage to corners can be easily repaired with epoxy glue.

 

Essential Tools:

 

• Elmer’s Carpenter Wood Glue
• Small hand plane
• Small (5 inch) Random orbit sander  ($30.00 Black and Decker Home Depot Use 120 grit paper {hook & loop} only. )
• 120 grit paper for orbital sander
  
  Note: The small hand plane and orbital sander are essential.  Without them you are wasting your time and money.

• Hammer
• Small wire cutter
• 1  inch brads (in the picture below it is next to the dime on the small piece of wood)
• Metal 2 inch paint scraper
• 3 inch sponge roller
• Elmer’s Wood filler

 

 

 

Canvas Stretcher Frame

The stretcher frame  presented here is 20 x 24 inches.  They are easily put together and make an excellent frame for the Luan plate.  These low quality stretchers will  NOT make perfect square corners.  But that is not important for our purposes.  What is important is that the Luan plate has perfect square corners, and that is accomplished at the time you purchase them by having the store cut the size you need. 

Step 1.

Assemble the stretcher bars, BUT DO NOT GLUE THEM TOGEHER!  Once assembled and laid on a flat surface you may notice that the frame does not lay flat.  If that is the case disassemble and try putting it back together in a different order.  This often helps.  If it is a total wash out attempt to locate which stretcher is producing the problem and replace with a new one.   These stretcher bars are readily available in such places as Michael’s Art Supplies. 

 

20 x 24 frame made from canvas stretcher bars

 

While you may find a perfect set of stretcher bars that make square corners the reality is that the wood you had cut will have perfect square corners but not the frame you assembled from the stretcher bars.  However, the frame will be close but you have to sort of nudge and fudge the bars to fit to the square corners provided by the Luan plate.  This means that after the frame is assembled you will have to tap out some of the bars to meet the dimensions of the plate.  This results in gaps at the corners but not enough to cause problems.  In the following photo notice the gap made after tapping out the bar to meet the perfect corner of the plate.

 

   

 

 

To get an alignment first assemble the bars then lay the plate on top to see what corners on the frame need to be pulled apart.  When completed some parts of the frame may actually extend beyond the plate.  In the following photo a pencil line shows this extension. This part will be trimmed after gluing using the small hand plane.  None of this is hard to do but it takes a bit of patience.  Notice that all corners have an original marking of numbers.  This keeps things consistent should you have to pull the frame apart.

 

 

This particular frame has a ridge on both sides that is used to keep canvas tight.  A bead of Elmer’s wood glue is place on the ridge.  You can purchase stretchers bars that are flat on one side which would give a wider gluing surface.  However, gluing to flat surface of a ridge provides plenty of gluing surface.  YOU CANNOT GLUE TO A ROUNDED RIDGE.

 

 

The Luan plate is then laid into position  and tacked down with wire brads. (Remember that the frame was nudge to conform to the corners of the plate).  Use a liberal amount of brads to make sure that the plate is tacked down at all contact points with the plate (1 brad every 4 inches or more if necessary).

 

 

It takes about 40 minutes for the glue to be dry enough to remove the brads.  Remove the wire brads carefully by using a wire cutter to grab the brad at the base and roll the cutter over onto a metal paint scraper.  This keeps the cutter from digging into the soft wood while you roll out the brad (always roll out in the direction of the slant of the brad if any).

 

 

Fill in the holes left from the wire brads and any deep fissures or mars on the plate with Elmer’s wood filler.

 

 

 

After the wood filler is completely dried sand down the board till smooth using the random orbital sander.

 

 

Using the hand plane trim the edges of the bars that extend beyond the plate.  Be very careful not to catch the edge of the plate as it will easily tear.

 

 

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GESSO

 

The goal of Gesso application procedures is to achieve a completely smooth painting surface that does not have the hills and valleys that are part of canvas weave.  This goal requires a minimum of 7 applications of Gesso.  The final result is a glass like painting surface that allows for fine detail.

 

Applying Gesso: Step 1 (Three thin coats-light sanding between coats))

 

Objective: to apply thin even coats of Gesso with plenty of drying time between coats.

 

Drip Gesso onto the board and using a 3 inch sponge roller:  roll out the Gesso (rolling with the grain) onto the plate.

 

 

 

Sand between each coat.  Apply  3 thin coats (do not use a brush: use a sponge roller only) and sand between each.   The first thin coat should dry for at least 24 hours.  Each remaining coat should have at least 12 hours of drying.  

How you apply the Gesso will affect the outcome.  During the first two or three coats it is fine to press down a bit on the roller.  This pushes the Gesso into the fissures on the plate.  However, subsequent coats should be done with minimal pressure on the roller.  The result is a speckled effect.  When it dries there will be an abundant amount of little beads on the board.  Which means the coating is a bit thicker and is now covering the fissures.  These beads are easily sanded down so that the final product is a smooth finish.  This takes a bit of practice to determine how much Gesso and roller pressure to use.  

 

Make sure you coat the edges of the frame and plate with Gesso.  This is important especially for the plate.  Plywood edges are fragile and the Gesso is a good protection for them.

 

 

Applying Gesso: Step 2 (Two thick coats- heavy sanding between coats)

Objective: Apply liberal coats of Gesso to cover the open grain that may be present on the plate.  This step is primarily a layering of the Gesso using liberal amounts of Gesso and pasting it on the board.  Think of how a cake is layered with frosting.

 

Step 2 requires application with a soft brush or sponge brush (DO NOT USE A ROLLER).  This is a bit tricky, but the idea is to drag liberal amounts of Gesso over the fissures cause by the open grain of the plate.  A roller cannot do this because the roller will simply continue to press the Gesso into the fissure but never bringing it to the top of the fissure.  This requires using a brush that does not press the Gesso into the fissures.  Don’t try to paint down the ridges between the brush strokes.  The must always be in the direction of the grain.  Each coat should be sanded with 120 grit.

 

Applying Gesso: Step 3 (two or three light coats- no sanding between coats, light sanding of last coat)

Objective: To produce a smooth surface across the entire board.  It is at this point that some patching may be necessary prior to using the roller.  Any remaining valleys should be lightly filled with Gesso, applied with a soft brush and allowed to dry prior to using the roller.

After repairs are made on any scars or valleys a roller is used to applied the last few coats of Gesso.  Do not sand except for the last coat.  Just prior to sanding the entire surface should be even with a speckled look. 

 

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The next step is to spray paint over the Gesso with a oil based primer ( as well as the back of the board).  This has to be an oil based primer!  The spray paint should be enough coats so that you have a slick surface to paint on. This will protect your brushes from tearing if there are any rough areas of Gesso left after sanding.  A few thin coats of white primer can save you a lot of time and money. No matter how smooth the Gesso surface it is still extremely hard on brushes.

Apply the spray paint in thin coats.  The paint will fill in any remaining mars and leave a smooth surface.  The number of coats simply depends how smooth you want the surface of the board.  Make sure you apply some paint to the frame edge.