The Framers Forum

Gentlemen,
I appreciate that I'm not a framer ~ or at least not in the sense that I make a living from the practice.
And I also appreciate that I keep on asking if i can pick your brains ~ but sometimes I do require some help.
Please do say so, if you find this at all unacceptable.

I have not yet done anything at all with canvas.
I have however, bought some artists canvas and some timber for stretcher bars (those, and wedges, I can easily make, to any size)
I have also bought two large(ish) (30" x 20") prints (Grimshaw & Wontner)
With each of these I intent to practice stretching canvas over bars (I've read a lot and viewed some youtube)
The aim is to finish up with the Grimshaw & Wontner of a sufficiently acceptable standard to be able to hang them at home, without too much ridicule from family, friends(?) & neighbours.

The info I've yet to come across, in any conclusive form, is: -
1. Are there any particular framing sections which are designed specifically for use around a stretched canvas package?
2. Or do you just select a appropriate profile, with a rebate sufficient to accommodate the package?
3. Is it acceptable to provide a window mount (single or double) to keep the canvas from the glass, or is the norm, and good practice, to always use a slip?

TIA
Jack

Nothing too difficult about putting a canvas on stretcher bars.

Firstly, because of the nature of canvas (lots of different grades), it is preferable to use bars with expanding joints. You can buy these off the shelf in incremental sizes. They have a double-joint on each end so that they force-fit togther. You should first knock the frame together (there will be a raised lip on one side which should point up). Check for squareness and make sure the opposite sides are equal length.
Once you have done this, offer up the canvas and feel about so the edges of the frame are aligned with the edges of the image. Hold it while you put a couple of staples in the middle of one of the long sides. Then grab a handful of canvas on the opposite side and pull it tight. No need to overdo it. Check that the alignment is still good and put a couple more staples in that side. Repeat this on the short sides.
Then it's a question of working toward the corners. Don't complete one corner and go on to the next. Pull the canvas toward the corner - add a couple of staples and then rotate to the next corner. Keep going round the corners in order. The idea is the get the canvas on without introducing any waves. Once you have reached into all the corners it should be reasonably flat and not flopping about. If you look at it obliquely while facing a window you can spot any bumpy parts. Don't worry about them. The expanding bars have slots to take small wooden wedges. (8 off). Tap them all lightly in. You don't need to get the canvas drum-tight. The term 'stretching' is misleading in this respect. Most of the time you will not need any extra tension at all.
But the wedges should always be put in so you can correct any small bumps or waves or re-tension sometime in the future. Do this carefully. A wave won't always disappear immediately. You'll notice that each wedge forces the joint apart in a different direction. You have to pick the one(s) that will apply force in the right direction to pull out the wave. Don't knock them in too fiercely. A little tap and leave it to relax - repeat until it's flat. Most canvases are fairly tough, but some aren't.
Once it's flat you can fold any excess around the back and staple it down to the backs of the bars. With a bit of practice you can do nice neat corners, but there will always be a slight bunching there. Don't cut bits out of the corners to make it neater.
Because of atmospheric conditions an canvas may go slack later. If it's on expanding bars it's usually a simple case of tapping the wedges in to restore the tension. For this reason the frame should have plenty of elbow room in the rebate. And also why you should never make the frame until you have stretched the canvas. What started off as a 20x30 could easily 'grow' a quarter of an inch after stretching. Most bigger mouldings that are intended for canvases have a reasonably generous width in the rebate. Smaller ones generally don't. Sometimes you have to machine out and extra 1/8" or so to get it in satisfactorily.

There are other systems that have emerged so you can make your own stretcher frames and still be able to have expanding corners. None are as good as the time-honoured system, but they do allow you to make non-standard length bars. Custom sized bars are obtainable - at a price.

As for glazing, that's a matter of personal preference. I never glaze oils on canvas unless there is a good reason. Glass will keep them clean, but a newly painted oil ideally needs to have free air circulation. By newly painted I mean 2 years or less. Oil paints can take 100 years for the paint to dry (cure is a better term).
Others will have different views on this.
Canvas prints are different in that any damage is near impossible to repair. They don't need air circulation so there may be a case for glazing in this case. You can use a spacer on a slip or a small moulding under the glass to achieve this.

Hope that's some help. When you have done a few you'll think it's easy.

There is a "How To" pdf on the Lion website - it is in the "Info Store".

Can be a bit difficult to navigate to so to save you the time here it is:
It is worth finding some canvas and practising.