Stretching Pre-Primed Canvas
 

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

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.

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.

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!

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.

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.

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.

:exclamati 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!

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.

After the painting is finished...
 

As I just stretched a canvas with the portrait already on it, I would like to know if anyone else does this regularly. Are there any problems that I should know about before I do it again? Thank you for any and all advice.

I would think there would be great potential for distortion in doing that, if there is the least bit of uneven tension in the stretching process.

Carol, I usually glue mine to panels when I have a "keeper" on unstretched canvas. I varnish after I glue it to the panel, though I'm not sure it would make any difference if you varnished first. I think there's a thread somewhere on the Forum about gluing linen to panels.

Carol,

That is a definite NO!

The stretching process creates innumerable fissures in the surface of the paint that could lead to cracking in the future.

Never, ever!
 

Thank you, Sharon. I will NEVER, EVER DO IT AGAIN!!!

This is a very interesting thread Garth, someday I'll try to use pliers, sometimes I stretch many canvasses on the same day.

I don't use tacks, I use a stapler instead, do guys see any problem about it?

Hi everyone,

Here are my two cents worth on the stretching after-the-fact issue, if I may...

Sharon,
If the painting is new and if it has been painted on pre-ground canvas (both of which are my assumptions regarding Carol's painting) then I think the after-the-fact stretching shouldn't cause any problems, so long as it was evenly done and didn't distort the image. As you know, paintings are removed from stretchers and then rolled for shipping and then re-stretched all the time. Of course, the initial thing was already stretched. But, really the same would apply to pre-primed canvas which is factory-stretched. The key to doing it, as I said, would be to take considerable care in uniformly stretching and not to over-stretch. Young oil paint films and grounds are quite flexible. Perhaps you've had a bad experience with this, yourself, but I have never seen fissures develop in the paint or ground layer from stretching an after-the-fact oil painting done on pre-primed canvas, and I've seen a fair number of such paintings.

Linda
I'd say that gluing after varnishing might present at least one problem; as you normally have to apply pressure to the surface to let the glue do its work, that could scar or mar the varnish. That's about it, though. What do you think? Also for anyone who uses a lot of heavy impasto and surface effects in their paint, gluing after-the-fact is not a good idea because that same surface pressure may flatten out their sought-after paint effects.

By the way, I use those tacks, too. I've even applied them cosmetically to a panel painting just for their nice look!

Best.

Juan

A big, "whew".
 

Juan, thank you , thank you, THANK YOU. I had planned to glue the canvas to masonite instead of stretching it. HOWEVER, its size seemed a bit too large to do that (17 " x 18 ") and the buyer is older (hmph..not too old!) and conservative. (a retired cop and his wife). It was recommended that the conventional canvas would be more easily accepted by the "Commish". And (...drum roll...) it WAS. I was so very concerned that the belated stretching would be a problem, that your post was a real relief as I didn't want to do it OVER. The canvas was taut and evenly stretched as my helpful husband helped while I "supervised". I thought it looked perfect and the "Commish" loved it. It looks as though I may be doing a number of other police officers from the same area. As an outcropping of this, I find that I would enjoy doing a series about officers in their work environment. (showing the brotherhood so frequently portrayed in the fire fighter genre).

Thank you again. I am seriously enjoying your articles in International Artist on drawing.

Carol :thumbsup:

Carol,

You're most welcome, and thank you for the compliments on my articles.

Best of luck with your "Boys, and Girls, in Blue" series.

Juan

Hi Juan,

I don't use too much pressure when I glue my panels to my completed paintings; I just throw on some big art books. My paintings are neither super-smooth nor super-chunky so I don't see scratching of varnish or flattening of impasto. (I use Gamvar varnish with some wax medium to dull the shine a litte, maybe this helps?)

Primed linen taped to a board is great for open studio settings. I am really picky about placement on paintings and I get upset at myself when I'm off an inch or so. I can recrop later to a square, oval, horizontal format, even a circle if I feel like it later on.

I have a closet full of rolled up paintings on linen. How old is too old to stretch, do you think?

(And I love your IA series, too!)

Great suggestions everyone, in the nick of time for me. I have a few additional questions:

Can one request the help of a spouse and still remain married after completing the stretching ordeal?

I need to ship said stretched 6'x4' canvas overseas. What is the best way to do this? Remove, ship and restretch?? after all that? OR...Crate??

help.

Stanka,

If I vere to trust anyone to do the job of restretching such a finished painting I would search for a person from an art supply shop. Many shops have a person that handle stretching of new canvasses for sale in the shop. Maybe your client could persuade such one to do the job. Or a framer.

Allan

Thanks, Linda. Yes, I guess that care and moderation are what counts in gluing-after-the-fact. Like you, I am fussy about placement, and I have taken table-saw-to-panel quite a few times,well after a painting is finished and varnished, and am about to again. In this recent case, I have, in fact, removed the varnish but that is because I am repainting a bunch of stuff, but that's another story.

Juan

Stanka, most people I know that have stretched canvases of that size would roll them for shipping, and have a trusted person on the other end, re-stretch them. It is much less expensive to ship, and I assume that is the main reason to do it.

Linda and Garth may recall that Paul Newton had his award winning painting at the PSA conference rolled up to ship from Australia. He rolled it back up and took it on the plane home, too. It was a commission, so it was indeed something that he needed to be careful about. I'm sure it was done on commercially pre-primed acrylic gessoed canvas. Anyway, it wasn't too old.

Oh, yes, Linda, as far as "what is too old" goes, I don't really know. But, I imagine you can get away with a lot, depending on the thickness of paint and on the particular ground. I have a couple of paintings from when I was 12 years old that are rolled up and, when unrolled periodically, do not show any cracks whatsoever. They were done on canvas paper (whatever that is). On the other hand, I have 6 year old pre-primed canvas from Rigacci's in Florence, Italy, on a wide roll that is all cracked and fissured. It is useless. Paintings done on it are very crack prone already. The priming is some sort of glue-chalk concoction, and no matter what the claims of flexibility are by the manufacturer, it isn't.

Juan

Thank you Allan and Juan.

I suspected rolling would be the most feasible option. Its always so tricky when you're dealing with commissions. I like to at least act like I know what I'm doing ;)

Regards,
Stanka

A picture guide to canvas stretching
 

To all,

I have added a picture tutorial here in another thread .

I hope it proves useful. It relates to the initial post of this thread with the written instructions.

Garth

Or you guys can just use stainless steel staples and call it a day!!!
Richard Schmid uses cheep staples and varnishes them so they don't rust...

Beats cracking your fingers under a tack hammer!

I'll second Tony on the stainless steel staples. Regular staples rust.
The staple gun is a wonderful invention! I can handle the canvas stretcher tool and the stapler, and do the whole thing myself (but not six foot canvases!).

I would assume that one purpose of the copper tacks is to look pretty for the client?

My husband and I stretch my canvases together. One of the problems we had using a staple gun (electric) was the varying hardness of the stretchers. Sometimes the wood was so hard the staple would not go in all the way or it would be too soft and the staple would go too far and cut the canvas. We couldn't tell what to expect, even on the same stretcher bar, because sometimes the wood is pieced. So we switched to tacks and it works much better.