Stretching Pre-Primed Canvas

Garth Herrick · 01-04-2005, 03:44 PM

Here's some info I just posted over at the nell'arte forum, over the question of how to deal with the difficulty of stretching oil pre-primed linen, and I thought it would be useful here too in this Forum:

When you are using the canvas pliers on pre-primed linen (Garth's personal method):

1.) First make sure your stretcher bars are secured with temporary screws in each corner to keep them from slipping out of alignment or out of square (this will invariably happen if the corners aren't secured). You will remove those screws again when you are finished, so that the keys you tap into the corners can do their job.

2.) Start with stretching accross the shorter dimension, then the longer one. This aids in spreading the tension more evenly taut. Get these pulled very taut, or you may have to reset them more taut on a second try. Doing this, get the canvas positioned and tacked on all four sides, with just the first tack in the center of each stretcher.

3.) Next stretch temporarily to each corner, pulling firmly, and tack temporarily to both sides of each corner (8 tacks total). The reason for this step in the procedure is to pre-condition the pre-primed canvas to behave better in horizontal tautness along the stretcher bar. Without doing this, you will tend to find tension bunching ripples toward the center of each side in the finished canvas, which can't be doctored or removed. This tendancy is always more severe accross the longer dimension, due to the more severe angularity of the stretching tension.

4.) Now you can proceed as usual adding tacks outwards from the center, short dimension first, then long dimension. You may speed things up along the short dimension/long stretchers by adding two tacks to one on the short stretchers, until each row of tacks is made even distance from the corners. IMPORTANT: For evenness of tension, as you pull the canvas taut with the pliers, you must take extra care to match the tension you previously pulled for the last tack... no more and no less! A change in tension will leave a subtle but permanent tension ripple as an artifact of your technique. The way you can judge if the tension is correct is by observing the canvas behavior just in front of the previous tack. If the canvas starts to bunch up before that tack, then you are stretching too taut, etc. Only place one tack with each pull of the pliers, even though the pliers are so wide. Two or more tacks with each pull is asking for uneven tension trouble.

5.) I bet you all know the rest!

You should get excellent, ripple free [drum -tight] results by this method, with the most unforgiving of pre-primed canvasses.

Happy Stretching,

Garth

Sharon Knettell · 01-04-2005, 03:57 PM

Thanks Garth,

Stretching primed canvasses can be a real muscle burning workout, especially in the larger dimensions.

One thing that has really helped me is a very good canvas plier, not the $12-20 cheapos that rip the canvas. I have a $90+ molybdenum Holbein that has a 4" rubber grip that really helps in stretching the canvas evenly.

David Draime · 01-07-2005, 11:23 AM

By the way Sharon, where can one find the $90+ molybdenum Holbein that has a 4" rubber grip ? Sounds great as I've always had trouble with my el-cheapo's.

David

Sharon Knettell · 01-07-2005, 01:33 PM

Quote:

Originally Posted by David Draime

By the way Sharon, where can one find the $90+ molybdenum Holbein that has a 4" rubber grip ? Sounds great as I've always had trouble with my el-cheapo's.

David

Click on the Dick Blick site on the upper right of this page and use the search on the site. Type in Holbein molybdenum plier. $89.95.

I am not sure it is exactly 4" but it is much wider. I had so many of the others break off in my hands while stretching canvas.

Michele Rushworth · 01-07-2005, 07:37 PM

Thanks for this tip, Garth, especially for step 3. Those mid-stretcher ripples on the long sides have always been a pain in the neck!

Linda Brandon · 07-26-2005, 09:45 AM

Garth makes it sound so easy. I'm still not happy with the way I'm stretching my double-primed oil linen.

IIs there a special method for making a '"gallery wrap" canvas (where the fabric folds all the way around the edge)? Also, does anyone have a step-by-step or illustrated method of folding a great corner that doesn't involve cutting part of the (bulky) linen)?

Somebody once stretched some oil double-primed linen for me and ended up using a heat gun on the back of it to soften the ground and make the fabric more stretchable. This probably isn't good from an archieval standpoint, but it worked.

Michele Rushworth · 07-26-2005, 10:19 AM

Next time you're in Seattle I'll show you how I stretch my double primed linen. No need to cut the corners on the fabric, drum tight results. I don't know how to do do gallery wrap stretching, though.

Sharon Knettell · 07-26-2005, 03:07 PM

I, ahem, do a gallery wrap on my big canvasses. Let me tell you, plan to spend a day, lots of sweat and more foul lanquage than you are used to using.

I put a large piece of plywood, bigger than the canvas stretchers, on two saw horses. I have adjustable metal ones so I can make it the most comfortable height for me to work easily.

Cut the canvas about 5" wider than the stretchers-this is good for the 1 3/4" depth Twin Brooks stretchers I use. I usually draw a pencil line the size of the stretchers on the back and front of of the linen to use as a reference to keep it straight. I staple the first staple the usual way, in the middle but on the back of the stretcher, followed by a second and third on either side. I then staple the opposite side pulling the canvas away from me using quite a bit of torque on my molydenum pliers. It takes a bit of practice. I cannot pull from the other side because the canvasses I use are generally too large to reach the other side. You can do a standard stretching procedure if your canvas is a reasonable size.

Follow this procedure on the other sides. You will need the three staples, especially on a larger canvas, to allow you to pull the canvas tight enough without them pulling out.

The Ralph Mayer book has a great diagram on making canvas corners. I do not make diagonal folds on the corners, but I bring the canvas to and over the edge on the sides. I fold the top of the canvas edge so the edge is square to the stretcher edge and pull it over the tucked side edges. It is hard to describe but if you fool with it it works great. I do not cut anything and I always have a canvas to show in a pinch. I paint the edges.

I also work from the center to an edge and start again to the adjacent staples and work toward the corner I just finished. I put the bulky part of the edges on the top and the bottom. It can take a lot of restretching, so don't tamp the staples down until you are sure it is perfect.

I hope this helps.

Linda Brandon · 07-26-2005, 04:10 PM

Quote:

Originally Posted by Sharon Knettell

I, ahem, do a gallery wrap on my big canvasses. Let me tell you, plan to spend a day, lots of sweat and more foul lanquage than you are used to using.

I should have made Garth stretch a canvas for me when I had him trapped in my studio last month.

Sharon, I'm printing out these instructions and I'm going to give it another try, thank you! I just got back from the art store, where I impulse-bought some copper tacks for their Old Master panache. Maybe I'll try this as well but I predict even more foul language if I use them.

Michele, I will take you up on your Seattle offer one of these days!

Sharon Knettell · 07-26-2005, 05:54 PM

Linda,

Alas, you cannot use tacks on this application unless you have three hands, one to grip the canvas, one to place the tacks and one to swing the hammer. You can do it on a smaller canvas but not on a biggie, I have tried. I prefer the tacks myself as they are indeed more elegant.