SnitzerArt.com ~ Classic Oil Paintings & Drawings

Important Note: Try to do your stretching in a dry environment. Humidity shrinks the fibers on linen fabric and as a result, a humid environment will initially give you a very tight stretch, but when the canvas is introduced into a dry environment at a later point, it will lengthen the fibers and as a result, will slacken, sometimes significantly.

Basic Supplies and Setup:

• Canvas Pliers
• Stapler with staples (3/8” or less on staple length) or a Tack Hammer with copper coated tacks
• Stretcher Bars
• Stretcher Keys - Tightens the tension on the stretcher bars
• Canvas - Cotton or Linen
• Pencil - To align and mark frame on canvas
• Razor Blade
• Ruler - To check frame is squared and to measure canvas to be cut

Important Note: NEVER use water to tighten tension on a slackened canvas. Moisture on the fabric is far from a permanent method of tensioning the fabric and can actually rot or damage the unprotected fibers on the back of the canvas. Either use stretcher keys in the frame to restore tension or simply restretch the canvas over the existing frame.

SETUP:

1. Assemble and square up the stretcher bars, either by using a ruler to ensure a consistent measurement around the stretcher frame or by using a known 90 degree angle such as a door jam or a mirror to check the squareness of the corners.

If you have no intention of using stretcher keys or if the frame is having a hard time staying square during the stretching process, you could secure the frame together with either staples or triangle corner pieces that will keep the frame squared and immobile. Keep in mind that if you’d like to use stretcher keys to tension in the future, it may be necessary to remove staples or corner pieces that were attached to the frame.

2. Cut out your canvas, ensuring that you leave a 3 inch or 4 inch margin depending on the size of the stretcher bar frame. Heavy duty stretcher bars can sometimes require more margin in order to get a complete wrap. Always try to error on the side of more fabric than less, as it can present an issue in the future if you need to restretch the canvas. Never cut off the excess material when you are done stretching. Ensure the stretcher frame is centered on the canvas and that the weave of the fabric is in line with the frame. If the weave is angled at all, it can lend itself to uneven tension on the fabric as the fibers pull on the frame.

3. Find a long horizontal side first. This will be the first side to be stapled or tacked down. Place a single tack or staple in the center of this first side. No stretching with the pliers is required at this point.

4. After placing the first tack, go across the canvas to the other horizontal long side and find the center. Now using your pliers, grasp the canvas at the center portion and with slow even tension, pull the canvas tight, but not tight to the point where the canvas face develops small creases or crinkles on the fabric. Place your second tack or staple in the center and repeat the stretching for the other two sides that have not been stapled in the center yet.

5. You should notice a diamond pattern on the front of the canvas. This pattern develops from the tension on the canvas from the first four tacks or staples that were placed in the center of the sides. If you don’t see this pattern at this stage, work around the sides, remove, tension, and secure the centers again with one staple or tack until the diamond pattern develops.

STRETCHING:

These next steps are where the canvas stretching process goes a bit unorthodox from conventional practice. Instead of continuing around the canvas, working gradually from the center out, we will be stretching the canvas from the corners in. This method, I have found, both from experience and quite a bit of research, ensures that a very even tension is applied on the fabric all the way around the frame. With proper setup, this will allow the canvas to have a very taut surface, essentially like a drum. Meanwhile, it also avoids problems that can show up as a result of uneven canvas tension, such as wrinkling or creasing of the canvas during and after the stretching.

6. Rotate to a long horizontal side and move to either corner of this first side. Using your pliers, pull with a slow even tension. Achieve a good tight pull, but not too tight, and place a tack or staple in that first corner.

7. Move across the canvas face to the opposing side and find the corner directly opposite of the first corner you secured. Tension the canvas and place the tack or staple in that corner.

8. Still on that same side, move to the unsecured corner and secure it, then move across the canvas face to the opposing side where you started, find the unsecured corner, tension and secure it.

9. Move to the two remaining sides now and repeat the same process again. First choosing a side, moving to an empty corner, pulling the tension slowly and evenly with the pliers, then securing that corner, moving across the face of the canvas to the opposing corner on the other side, tensioning and securing that corner and finishing off the remaining two corners that need to be secured still.

By this stage, if the tension was applied correctly while securing the corners, you should already have a decently taut canvas face that won’t give too much when pressure is applied by your finger. Don’t worry at this point if it’s not drum tight yet, that will come later when the rest of the canvas is secured.

10. Release the center staples only from the four sides of the frame. We do this step to release the tension on the canvas in the middle, as we will need this slack in the fabric as we start securing the canvas from the corners towards the center.

11. Repeat the procedure you used when you secured the corners. Move in about 1˝ inches from the first tack or staple in the corner and tension and secure the canvas, again moving to the opposing side on the canvas and securing that as well. Work in a Z pattern as you are securing the canvas. Place one staple or tack in the top left corner, then secure bottom left corner, secure top right corner, then bottom right corner.

12. Rotate the frame to the short sides, repeat the same process, again work in a Z pattern, secure one staple or tack in the top left, then bottom left, top right, then bottom right.

Work in this manner across the canvas, placing one staple at a time in each corner area. Check your tension while doing this process as well. As you slowly move closer to placing the center staple or tack, you should notice that the surface should be almost as tight as a drum at this point. If you rapt your finger against the face, a low bass boom should reverberate from the canvas.

FINISH:

13. Wait 24 hours after the stretching is finished, and if the tension on the canvas slackens, you can either restretch the canvas at this time or use stretcher keys to restore tension. The choice is yours and ultimately depends on if and how much the canvas looses tension and whether or not the stretcher frame has been permanently attached together. If the canvas looses a significant amount of tension, a restretch of the canvas may be the only recourse to fix it. If the canvas slackens moderately and the frame isn’t permanently affixed to itself, then simply using stretcher keys will help restore the tension.

Take note that larger canvases or canvases stretched in a humid environment may need to be tensioned after 24 hours or if introduced into a drier environment at a later date. Smaller canvases usually don’t require an immediate retensioning and can be usually be safely finished on the first day.

14. To finish off the final look of the stretched canvas, follow the procedure below to achieve professional looking folded corners:
a. Choose whether to fold in the corners on the shorter or longer edges of the frame first.
b. Release the tack or staple from the extreme corners on whichever two sides you chose.
c. With the edge that is released, grasp the canvas and fold it inwards to farm a parallel edge to the frame.
d. With the excess canvas below the corner, pull the excess material in with your other free hand and ensure that the extra fabric is tucked behind the fold.
e. You shouldn’t have any extra material poking out from behind the flap that was created. If there is extra material, ensure that your edge runs parallel to the stretcher frame and you have properly folded up the fabric into the back of the flap.
f. Tension the fabric with your fingers, place a tack or staple back in the corner where it was removed previously, then place a tack or staple on the end of the flap behind the canvas.
g. Repeat for the three other corners.

15. Secure the remaining fabric to the stretcher frame behind the canvas to finish off with a professional look.