Sunday, January 30, 2011

How To Stretch a Canvas

“How To Stretch a Canvas for Painting”. Stretch your dollars, define your dimensions….and then canvas your world.

canvas pliers (I recommend the ones that have a rubber grip)
Heavy-duty staple gun. “Powershot” is my favorite.
Wood Stretcher Bars: 4 total, (2 pair- each of duplicate length).
Canvas or linen.
tape measure

All stretcher bars come with at least one side that has a raised ridge along the edge (some bars are raised on both sides). If your bars have only one side with the ridge, make sure they are fastened together so the ridges are all on the same side. This matters.

Step 1:
Your support (stretcher bars) for the canvas must first be put together ;each length has a 45˚ angle on each end. Once they are joined you will have a frame (support) square or rectangular with 90˚corners.
Measure to insure you have a perfect right angle (90˚) on each corner. To check this -measure each diagonal with a tape measure and confirm the diagonal lengths are the same . The example below shows each diagonal to be 17.5 inches.

Once you are confident the bars all have a 90˚ angle, staple each corner of the wood bars to secure them. If you wish to use canvas keys later (small wooden wedges), you can remove these staples once the canvas is attached.

Step 2:
Linen and/or canvas can be purchased either in a roll or by the yard. I think the roll is a better value, but if you are trying this for the first time, you might want to buy your canvas by the yard for your test trial. I will use the word “canvas”to represent both canvas and linen. Notice there is a gesso side and a raw side to your canvas. You will want to do your painting on the gesso side.

Amount: You will need your fabric to be a minimum of 4” larger than the dimensions of each length of your desired canvas size. As an example – a canvas size of 16”x20”, would require a swatch of canvas to be no smaller than 20”x24”, or as another example an 8”x10” would require a sample of 12” x 14”.

Step 3:
Layout: Important- do not fail to pay attention to this step. Make sure that when you measure and lay out the fabric, the woof (weft) and warp is perpendicular and parallel to the stretcher bars. ( Basically the threads that run horizontal must line up with the horizontal bars. The vertical threads must be parallel to the vertical bars. If the threads do not line up with your bars, your finished canvas will have puckers or ripples.

Step 4:
Cut the fabric so you have 1.5” or 2” beyond each stretcher support. This will allow you to have enough fabric to grab the canvas over the wood bars with your pliers. Example:

Step 5: Lay canvas -Gesso side down. Place your stretcher bar support on the raw unprimed side of the canvas. The raw fabric side should be facing up toward you. Make sure the wood support frame has the raised lip facing down against the raw canvas.

Once your support and canvas are properly aligned, lift one edge of the canvas and staple it to the support. Do this with care, so you don’t disturb the layout position of the canvas and support.

Step 6: On the opposite end, use your pliers to stretch the canvas over the support, so now you will have 2 opposite ends stapled.

Step 7: Now rotate your support (wood frame) and canvas and stretch a 3rd side and staple along end.

Step 8: Repeat on the 4th unattached length. You should now have 4 sides stapled. It will have a diamond shaped pucker on the gesso side of the canvas. example:

Step 9: Now you will pull and staple the canvas on the left side of the existing staple- and then the right side of the first staple. Keep your staples evenly spaced, approx. 1” apart. Rotate and repeat this process until you have staples all 4 sides. The diamond shape pucker on the front of your canvas will get larger and less pronounced as you work toward the edge of your support. NOTE: you are only putting 2 staples in at a time and then rotating. Do not attempt to staple an entire length or side all at once. You must keep rotating after you have added 2 staples.

Step 10: Repeat step 9: 2 staples 1” away from each existing staple -and rotate. 2 staples and rotate, 2 staples and rotate, until you have completely fastened the canvas across the entire edge of each length. The diamond pucker on the front should be completely gone now. Your canvas should look like the example and have no puckers. (If you have puckers, go back and check what is off. Either the canvas was not true to woof & warp, or your stretcher bars were not at true 90˚ angles. You will need to remove all your staples and try again).

Step 11: Securing the corners and finish: fold one corner over, make a pleat and fold over again as shown. Then staple the corner down.

You’re done! Bravo.