Stretching a Perfect Canvas

(Acrylic Gesso Ground)

Covered in this article
• Materials
• Preparing the canvas for stretching
• Pre-Gessoing the canvas
• Stretching the canvas onto stretcher bars
• Folding the corners
• Final coat(s) of gesso
• Detailing the surface
• adding tension

Making your own canvas is a very rewarding experience. Like painting, it is an art that takes practice and one that a remarkably few painters can do well, if at all. Being able to make any size and depth, using any canvas or linen with your choice of grounds gives the artist total control of the painting surface. While the initial cost to start may be more expensive than buying some pre-stretched canvas, the skill will quickly pay for itself.

Most of the pre-stretched canvas you buy in the store uses cheap, inferior materials and has a cookie-cutter look that says “I was made on a machine in a sweatshop in Thailand.” When you make your own, you have the option of purchasing sustainable materials, such as FSC Certified Lumber, organic cotton canvas and linens and even hemp canvas, which also has mildew resistant properties.

These step by step instructions will help you create the perfect painting surface with a beautiful hand-made look and feel. This article has more than enough information to help you stretch your best canvas yet.

Materials needed

Part I

• Gesso brush
• Gesso
• Canvas
• Staple Gun /staples
• Lint brush
• plastic bag or wrap

Part II

• Staple gun /staples
• canvas pliers
• hammer
• sharp razor blade
• pre-gessoed canvas (from Part I)
• stretcher bar assembly (frame)

Part I – Preparing the canvas for stretching

1. Tear the canvas down to size.

I like an extra 2.5 inches all the way around plus the width. So if you you have a 20 x 20 x 2 inch stretcher bar assembly, you will need a 29 x 29 piece of canvas. The extra little bit of canvas will allow you to get a better grip on the canvas with your canvas pliers and help you get a tight stretch.

Start the tear by making a 1/2 inch cut, then tear the rest. Tearing the canvas instead of cutting it will give you square corners and straight edges. You can also prep a big piece for multiple canvases and tear it down later.

2. Stretch the canvas on a wall or board

If you have a pre-gessoed canvas you can skip to Part II.

Pick a side to gesso. Sometimes knots in the canvas strings are more prominent on one side than the other. Staple to a wall or thick board such as drywall or homosote. Starting from the middle of the edges and working towards the corners, insert a staple every 3 inches. Pull the canvas as you staple to give a gentle stretch. Don’t pull so tight that the staples pull out. You want the canvas stretched taught, but not to tight. When you apply gesso, the canvas will shrink, if you don’t have enough give, the tension will pull out the staples.

3. Remove any lint or debris on the canvas using a lint brush or roller.

If you bought a folded canvas you will probably need to iron the creases out. You can use some spray starch to help the ironing. It is better to buy canvas by the yard or roll as ironing is very time consuming. If the canvas is severely creased or wrinkled you may wash the canvas in the washing machine and tumble dry on low, then iron the canvas as soon as you take it out of the dryer. Buying a roll of canvas, or buying it by the yard and rolling it around a cardboard tube at the store will save you time and frustration. Gesso will straighten the canvas a little bit, but usually the creases are too severe without ironing.

4. Apply the first coat of gesso

With a dry brush, apply gesso from the middle of the canvas all the way out to the staples. Applying gesso all the way out to the edges will add some strength to prevent tearing during stretching and hold the threads together so the edges don’t fray. Work the gesso into the canvas with your brush and keep the coat thin enough so you don’t see many brush marks.

If the gesso is too thick you may need to thin it down a bit with water in a separate container. You want the gesso thin enough so it is easy to apply and will soak into the canvas a little bit to adhere properly, but not so thin that the gesso soaks through and adheres your canvas to your board or wall. The thinner the gesso, the more coats you will need. If you apply to gesso too thick you may get adhesion and cracking problems.

Dragging the brush lightly and perpendicular to your previous brush strokes should get rid of most of the brush marks. Gesso shrinks a little bit when it dries, which will diminish the brush strokes slightly, but don’t expect miracles. If you have problems with the gesso being too thick, you can scrape some of it off with a spatula. If it is difficult to spread, you may need to thin it down with some water or acrylic matte medium.

Allow the gesso to dry fully. At least an hour in warm weather, overnight in cold or damp weather. You may use a hairdryer or heat gun to speed the process. Remember a hairdryer will dry the surface first, so the gesso may be dry to the touch but still wet underneath.

You can wrap your brush in a plastic bag until you use it again. It will be fine for a week or two. this saves time and water.

5.Apply the second coat of gesso

In the same manner as the first. This will take less time than the first coat. Stick your brush back in the bag, being careful not to get the old paint in the bag on the dry part of the brush bristles or the handle.

6. Remove imperfections

If you have any chunks of dried paint or brush hairs stuck in your gesso, now is the time to get them out. You can use a razor blade to gently scrape any imperfections off. If you like a smooth surface sand the canvas gently with 400 grit sandpaper. It is easier to start out with a canvas that has a surface texture closest to your desired end result, rather than trying to change the texture with gesso. So if you like a smooth surface, consider a finer weave of fabric, such as portrait canvas or linen.

7. Remove the Canvas from the wall

or board when fully dry and remove staples. The gesso should not be cool to the touch. It is best to let it dry at least overnight on the wall. Gesso takes about 3 days to fully cure, depending on the thickness.

PART II – Stretching the Canvas

1. Square the canvas to the stretcher frame

Begin by placing the canvas, gesso side down on a clean surface (a blanket works if you are working large and on the floor). Line the edges of the stretcher bars up with the weave of the canvas. I find this is easier if I look down the stretcher bars like a rifle. Having the canvas square will make it easier to stretch with an even tension throughout.

2. Staple the long side away from you

Fold the canvas over the edge of the stretcher frame on the long side opposite you. The edge of the canvas should be flush with the edge of the stretcher bar. put one staple in the middle on the back side of the frame (never on the sides). Pulling the canvas gently away from the first staple add 1 or 2 staples to either side of the first. You may also place a few staples on the sides to keep the canvas in place (which you will take out later).

3. Staple the long side closest to you

Fold the canvas over the side closest to you. Using your canvas pliers pull the canvas tight. This is the most important part to get a tight canvas. The harder you pull, the tighter the canvas. Be extra careful not to rip the canvas with the corner of your pliers. You may fold the canvas over so you are pulling a double layer of canvas. You may need to pull the canvas, then hold it in place with your other hand, then pull the canvas again. You may also pull the canvas a few inches to the right and left to loosen the fabric before going back to pulling in the middle.

Place a staple or two in the middle of the bars to hold the canvas in place. Add a few more staples on either side of the first staple. You will need to use your pliers. Also when you pull the canvas, pull a few inches away from the initial staples. If you pull to close to the staples they will come out and you will have to start over.

It is important to watch the weave of the canvas on the edge of the stretcher bar. The weave should run parallel to the bars. If the weave is irregular, meaning it forms a wave pattern or a slope, it will create uneven tension on your frame. Using a pre-gessoed canvas helps decrease the wave patterns as the gesso reduces the elasticity of the canvas and will also give you a tighter stretch when you finish. Keeping the weave parallel means the canvas and the stretcher bars are square to each other, which will make the next steps easier.

4. Staple the first short side

Pull gently with your pliers and staple. Pay attention to the weave between the staples on the long side. The weave should not bow in or out.

5. Staple the other short side

This side you can pull hard. Again the weave should be straight.

6. More staples

Working from the initial staples in the middle of the long sides, pull the canvas with your pliers and staple. The weave will tell you how hard to pull. The weave should line up the entire length of the stretcher bars. If it doesn’t you may have problems having enough canvas for the corners.

Alternate sides, adding a few staples at a time until all four sides are stapled about six inches from the corners.

7. Complete staples on 2 sides

Determine which side you want your folded corners. Continue to staple all the way to the end on the sides you do not want the corners. Tap the last couple of staples in with a hammer. This will keep a lower profile when you fold the canvas over.

8. Staple the corners

Fold the canvas over so the seam is at the corner and the fold is hidden. The angle of the fold will determine how much of a flap you have. If the flap hangs off the edge adjust the angle. The back of the canvas should lay flat without wrinkles. Put in a few staples in the corner. If you have a heavy duty staple gun you can put in 1 or 2 staples in the corner to hold it down. This is really the only area you might need a heavy duty staple.

Repeat for the other three sides.

9. Apply 1-2 more coats of gesso.

1 coat of gesso is fine for acrylic. This will seal all those cracks and give a nice finished look to the corners. If you feel you didn’t do such a great job applying the first 3 coats, you may add a fourth, especially if you are working in oil. If you are planning to paint in oil, your fourth coat may be an oil priming ground (more on that later).If you are using oils and paint the sides, make sure the oil doesn’t overlap onto the raw canvas, as this will cause the canvas to rot.

10. Clean surface