How to stretch oil paintings

How to stretch an oil painting canvas. If you are a bit D.I.Y. capable then stretching your own painting is a good way to save on costs. The tools required are either a staple gun or a hammer and small carpet tacks; some sort of pliers, the wider the jaws the better to spread the grab. Also a way of making sure the corners are square, this can be a set square as shown, but a large book or even the edge of a table can be used just as well.
	Stretcher bars are sold in pairs, so for example if you want to mount a 8x10 inch painting, you would buy a pair of 8 inch and a pair of 10 inch (1 inch = 2.54 cm) stretcher bars. They should cost under $10 or £7. Paintings over 40 inches need either heavy duty bars or an extra strengthener in the middle. Stretching over 40 inches does require a bit more expertise.
	As the edges slot into each other, they must be square, each corner must be checked and tapped into alignment. The overall size now needs checking, if - as above - the painting is 8x10 then that is the size your stretcher bar frame should be. When you buy a decorative frame for your mounted painting it will have a groove cut in the back for the oil painting to slot in, this will normally be 2 times 1/8", or 2 times 4mm, larger than the 8x10 to allow for the thickness of the canvas.
	You will notice a raised groove around the outside, this is the front, or painting side, the purpose is to keep the canvas of the wood, otherwise the wood may show through as a dark shadow border. It is advisable to staple the corners to stop them getting out of square later. If making your own bars, a small half round bead can be glued on for this purpose.
	The painting and stretcher frame now seen from the back. The next step is to align the painting on the frame and pop in the first staples. This can involve a lot of up's and down's getting it aligned. Tip Check the longest lines on the painting, ie; is the loch level? is the side of the building straight up and down? There is an order that should be followed when stapling, or pinning, this is to try and spread the stretch, avoiding waves on the canvas.
	This is stretching the canvas for staple number 2. Canvas pliers have wide jaws which lets you get a good pull without wrinkling the canvas. A normal pair of pliers can be used ideally with wide jaws, be careful not to tear the canvas.
	This is a suggested order for inserting staples. How many you use depends on the length of side. In riveting the distance between rivets depends on the "sphere of influence" which is how much area the rivet grips. Same with staples or tacks this varies with the thickness of the canvas. You will have to use your judgment.
	If you have to re-staple, at any stage it is not a big thing, it will not de-value your painting.
	Your painting should now be looking something like this.
	1 first corner 2 Pull tight but make sure you do not damage the front face. 3 Pull one side in tightly 4 Fold down and staple.
	Finished corner. Sticking out slightly on the fold, it depends on how thick the canvas is as to how neat the fold can be. As long as it fits the groove, you can tap it a bit flatter if required.
	Ready to go.

How to stretch an oil painting canvas.