Published in the
July 2012 issue of
Digital Paint Magazine
STEP BY STEP CANVAS STRETCHING
Assemble all materials and tools before starting.
(Step 2 through 4 are optional)
We will use Elmer's Wood Glue to bond the stretcher bars ends together. Because we are using pre-made stretcher bars that come ready to assemble we may need to sand rough edges that have resulted from the cutting tools used during the manufacturing process.
(Step 2 through 4 are optional)
Apply a small amount of glue to each end as shown. Repeat this for each of the stretcher bars before continuing to the next step.
(Step 2 through 4 are optional)
Using your finger, spread the glue around the surface of each of the cut ends as shown. Repeat this for the remaining stretcher bars.
Begin mating the stretcher bars.
Make sure that you fully seat the stretcher bar ends. If you see a gap along the seam where the ends meet, then you have not fully mated the two bars.
In this view, all four stretcher bars shown mated together. However, we need to ensure that all four corners of this assembly are square before the glue sets. (i.e. A, B, C, & D)
If you used glue (as shown in steps 2 through 4) wipe off any excess glue that has squeezed out during the mating of the stretcher bars.
Measure the distance between corner A and corner B.
Measure the distance between corner C and corner D.
Compare the two distances against each other. If the distances AB and CD are equal, you are square. If they are not equal, you are not square.
(In our example distance AB was .125 inch larger than distance CD, and we need to make adjustments as shown in steps 11 and 12.)
While firmly holding the stretcher bar assembly, tap the corner with a mallet that had the largest measurement.
(In our example we will tap corner A.)
Recheck all corners to make sure they are square. We can use the tape measure method shown earlier, or we can use a square ruler method as shown here. Hold the square ruler as shown and check that both inside edges of the ruler run flush along the surface of each stretcher bar. If the ruler lifts off on one side (not running flush along the entire surface) then your not square. Repeat this check on all the remaining corners. If your stretcher bar assembly is square, then you are ready to start the canvas mounting process.
Using light grade sandpaper, gently remove any rough or broken wood from corners.
Ensure the corners are thoroughly sanded and no rough edges are remaining.
Before laying down your giclee canvas print make sure there is no debris or wood pieces (that may have fallen off during stretcher bar assembly) which could damage the printed surface. A soft cloth work surface minimizes the chances of causing small scratches to your giclee canvas print.
Lay down your print (face up) and make a final close examination to ensure it does not have any damage.
At this point turn over your giclee print, so the image is face down. You are now ready to position your stretcher bar assembly.
Place your stretcher bar assembly over your giclee canvas print as shown.
Starting with the right side, carefully lift the canvas print and ensure that the image is wrapping around the front face of the stretcher bar. Repeat this on the opposite side, moving the stretcher assembly left or right as needed until you see the image wrapping equally around both sidebars.
Once you are sure that you have centered the stretcher bar about the printed image, draw a reference line along each side as shown. This reference line will come in handy later if the stretcher assembly moves out of position and you need to realign it.
As we did in Step 18 for the side positioning, we now want to center the stretcher bar assembly along the top and bottom bars. Carefully lift the canvas print and ensure that the image is wrapping around the front face of the bottom stretcher bar. Repeat this for the top stretcher bar, moving the stretcher assembly up or down as needed until you see the image wrapping equally around the top and bottom bars.
Once you are sure that you have centered the stretcher bar about the printed image, draw a reference line along each side as shown. We have now centered the stretcher bar assembly in both the vertical and horizontal directions concerning the printed image. We are now ready to begin the canvas stretching, wrapping, and stapling processes.
Starting with the top stretcher bar, wrap the giclee canvas print around the stretcher bar as shown. Be sure that the stretcher assembly has not moved out of the reference lines we drew earlier.
Holding the staple gun squarely on the canvas and stretcher bar, staple the canvas to the stretcher bar in the center of the bar as shown.
Check that your assembly looks like this - having one staple in the center of the top stretcher bar.
While firmly holding the canvas pliers, grip the canvas in the center of the bottom stretcher bar opposite from the first staple in the center of the top stretcher bar.
Using the stretcher bar as leverage, rock the canvas pliers forward (compare images from step 25 and 26) until canvas has stretched - notice that the canvas tightly wrapped around the stretcher bar.
Before releasing the canvas pliers, press your thumb onto the canvas. Holding your thumb in this manner will maintain canvas tension during staple insertion.
While maintaining tension by firmly pressing your thumb on the canvas, insert one staple. Hold the staple gun squarely on the canvas and stretcher bar and staple the canvas to the stretcher bar in the center of the bar as shown.
Check that your assembly looks like this - having one staple in the center of the bottom stretcher bar.
Once you have inserted the first two staples into the top and bottom stretcher bars as shown you should notice a slight tension pull on the canvas between the two staple points (i.e., points A and B.)
Using the canvas pliers, stretch the canvas starting on the left side and hold tension, applying firm finger pressure. (...I am keeping the pliers away from my body, and this provides less stretching and leveraging control. Because I'm not applying tension for the first side staple, I chose to use the pliers in this way. However, when you are stretching opposing sides it is recommended to hold the pliers so that they are facing toward your body as shown in images 25 through 28)
Insert one staple in the center of the side stretcher bar.
Repeat the stretching and stapling process as shown in steps 25 through 28. Be sure to firmly hold canvas with your thumb before removing the canvas pliers.
Be sure that when stapling opposing sides you stretch the canvas so that it does not droop or sag. Our assembly should now have one staple placed directly in the center of each stretcher bar as shown.
Flip over the assembly so that you are looking at the printed image on the front. Check that the image is centered both vertically and horizontally - you should see the image wrapping equally around all sides, and no 'white' border should be visible along the front face. Check that the image has not rotated clockwise or counter-clockwise so that it is no longer square with the stretcher bars. Also, check that the canvas is not overly loose or sagging. In the next steps we will tighten the canvas as we stretch, wrap, and insert the remaining staples, but now is the time to remove the staples and make adjustments if the position of the image is off or the canvas is very loose and sagging.
Beginning with the top stretcher bar (1), stretch canvas using canvas pliers and hold tension by applying pressure with your thumb.
Insert staples starting from the center staple and moving left with each new staple until you reach the left stretcher bar as shown. Use canvas pliers as needed.
Moving to the bottom stretcher bar (2), stretch canvas using canvas pliers and hold tension by applying pressure with your thumb.
Insert staples starting from the center staple and moving right with each new staple until you reach the right stretcher bar as shown. Use canvas pliers as needed.
Repeat the previous step for the left (3) and right (4) stretcher bars in that order. Remember to start from the center staple and move in the direction of the arrows (as shown) as you staple the remaining two sides. Use canvas pliers as needed.
Now we begin applying more tension when stretching the canvas using the pliers. Always have the canvas pliers facing away from your body during the final stretching and stapling steps for maximum tension and leveraging control. Starting closest to the center staple on the bottom stretcher bar (1) stretch the canvas, maintain pressure with your thumb, and insert two or three adjacent staples starting from the center staple moving left.
Move slightly to the left of the staples you just inserted in step 41, use the canvas pliers to pull the canvas tight, apply thumb pressure to maintain canvas tension, and insert two or three more adjacent staples moving in the left direction toward the left stretcher bar.
Reposition the canvas pliers closer to the left stretcher bar, pull the canvas tight using canvas pliers, maintain pressure with your thumb, and insert several adjacent staples.
Repeat this process until you reach the left stretcher bar.
Your assembly should look like this after inserting staples along the bottom (1) stretcher bar.
Repeat steps 41 through 44 for the top (2), left (3), and right (4) sides - in that order until your assembly looks like this.
A good test to see if you stretched the canvas enough is to tap the center of the canvas with your finger and listen to hear a drum-like sound. If the canvas was improperly stretched and is loose then it will not have this sound and will flop around as you tap it. Also, if you see ripples in the canvas then you have an uneven tension problem - the canvas is not tight.
Now we must fold and secure the four corners. Hold the corner of the canvas material as shown.
While applying tension, wrap the corner around the stretcher bar as shown so that the fold is on the side of the assembly. The fold should run at a 45-degree angle as shown.
While continuing to apply tension on the canvas material, fold it around the back face and hold securely in the position shown in preparation for stapling.
While holding the corner in position, insert several staples as shown.
Repeat steps 47 through 50 on the remaining three corners. Be careful that your folded edges are always on along the side stretcher bars. Your finished assembly should look like this when viewed from the back. Use your hammer to fully inserted all staples.