Canvas Stretching

You will need:

A wooden stretcher or strainer (the stretcher pictured is actually not a stretcher because it has no canvas keys which are the little bits of wood or plastic that can be used to stretch out the frame and make the canvas tighter) Although I will refer to it as a stretcher (confused yet?)

A Staple Gun

Canvas Pliers if needed, these can help if your fingers are not very strong or if you are stretching very large canvases

Canvas, this should be 3 inches larger than the stretcher on all sides

figure a

Begin by placing the stretcher on top of the canvas (figure a) 

 

figure b

Then staple in the middle of each length pulling the canvas tight (but not too tight!) and following the numbers (figure b).

figure c

The second ‘circuit’ of staples starts to the right of the first staple follow the numbers 5-8(c). You need to tighten the canvas at this stage before each staple taking care to keep the canvas fibres parallel The next ‘circuit’ follows the same rationale but to the left of the first staple along each edge (d) repeat this process until you are approx. a hands width from the corners.                                                                

figure d

 

There are a few different ways to fold the corners. I will try to will explain the easiest and neatest. First turn the canvas so the front (the surface you will paint on) faces you, then taking hold of the loose material (e), you need to stretch the material over the corner without putting a hole in the canvas by pulling it over the stretcher corner.

figure e



figure f

Quickly staple one side so you have a free hand (g).

  

figure g

While keeping the tension in the canvas fold the excess material along one edge and tuck the fold underneath itself l so you can’t see it (h). Keep practising this bit if you don’t get it straight away.

 

figure h

The back should look something like this (i). If during painting the canvas becomes loose, you can spray or sponge the back with water this will tighten the canvas back to the same state just after priming.


figure i

 

Priming

The primary reason for priming is to protect your canvas, board or other support from the destructive qualities of oil paint.

 

Acrylic paint can be used straight on to the surface or support (the support is your canvas, board or paper) but you may want to prime or use a transparent glue size (thinned PVA or rabbit skin glue) to give you a non absorbent surface so your paint doesn’t get soaked up into the canvas or board.

 

You will need:

• a canvas or board
• a priming brush
• water and Acrylic primer
• a spare jar or tub

If you dont have (or can't get) an acrylic primer you can make a cheap version using 2 parts emulsion and 1 part PVA Glue.

 

 

 

First you need to mix up a weak solution of primer about half water half primer. This will be your first coat (or size) this is to seal in all the little gaps between the weave of the canvas. 

 

Next, very simply apply enough coats of pure primer until you have the surface you require probably 2 or 3.

 

Be careful to apply each coat in different directions to ensure an even coverage and allow each coat to fully dry before applying the next.

If you have any lumps or imperfections in the surface use fine sandpaper to carefully sand then out.

  

If you are priming a smooth board (mdf or hard board) you may wish to give each coat a light sanding to remove brush marks. Also, if you thin the primer down a little the brush marks will be less distinct. Be aware this also means that more layers will be needed to cover the surface.

More complicated/old fashioned priming coming soon...

Paper Stretching

How exciting the first 'proper post' to The Brushroll. I thought I would begin with a simple bit of paper stretching. Very useful if you paint with watercolour but can also be used for painting with acrylic and oil.

The reason for stretching paper is to avoid buckling or ‘cockling’, which will occur if the paper has not been pre stretched and cause the paper to warp when you apply wet paint. Thick watercolour paper or cartridge paper can be stretched but be aware the more heavyweight the paper the longer you will need to soak it.

Once stretched you can either wait for the paper to fully dry or start painting straight away depending on the effect you wish to create..

 You will need: 

• Gummed paper
• Paper
• a board, a bit larger than your intended paper
• a sponge or large brush
• Water
• Drawing pins or a staple gun

 

First soak your paper, a bath or large clean sink is ideal for this, or you can load up the paper with water on your board using a sponge (making sure to wet both sides if you are using a sponge). Cartridge paper only needs to be soaked for 5 minutes or so, larger watercolour paper could need up to half an hour.

 



a

b

Then, smoothing out any air bubbles, tape down one side of your paper then smooth the paper, using the palm of your hand, towards the opposite side and tape it with the wet gum paper (b).

 

c

Repeat this process with the other two edges before pinning or stapling the corners through the paper and gum tape (d). This will hold the paper down as it dries and stretches it. Always dry the paper horizontally, if you dry it vertically all the moisture will sink to the bottom and stretch unevenly.

d

You can apply wet into wet washes straightaway, but you should wait for the paper to dry before applying any detail because it will act like blotting paper at this stage.

 

e

 

 You could also prime the paper to prepare it for oil painting. (more about priming in a future posts)