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Old 25-11-03, 03:07 PM
Camilla Camilla is offline
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Default How to fix a hole in a canvas?

When one of my paintings came back from an exhibition there was a hole in it. Of course noone wanted to take responsibility for that, let alone pay for the damages. Now I want to try to repair it myself.
The hole is about 2 x 2 cm and has an angular shape. The paint and the ground is cracked where the canvas has been deformed (I think the canvas has been leaning against a corner or something).
I have tried gluing a piece of canvas to the back of a test canvas using a mixture of wax, dammar and turpentine, but it comes off again easily - not much of a glue effect here. I have considered using rabbit skin glue as an alternative.
I asked two conservation experts who advised against gluing a piece of canvas to the back because this would disturb the way the canvas contracts and expands, which could lead to further damages. Of course both suggested that I let them do the job (for over 200£!).

The question now is: Is there a way I can make these repairs myself?


Camilla
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Old 08-12-03, 12:23 PM
hisstah hisstah is offline
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Dear Camilla,

I'm sorry I didn't see this post earlier and I'm glad you pointed it out to me. I'm very sorry to hear about the damage to your painting. It's been my experience that many galleries and artists themselves have no idea how to properly handle or store artwork. I have to repair a lot of things damaged this way.

In my instructions below, I am assuming that this is an oil painting with either an acrylic or oil ground. If it's an egg tempera, it will likely be much more fragile--mainly because of the chalk ground and you will have to be very careful about using water.

Your conservator friends are indeed correct--applying a piece of canvas to the reverse will restrict the expansion and contraction of the original canvas and affect it adversely. The combination of the additional canvas with the adhesive will cause a bulge in the shape of your patch to form on the front of your painting. In a worst-case scenario, the paint surrounding the patch will crack in a really disgusting way. I think what your conservator friends might recommend is a lining procedure to repair the tear, but it is very laborious and expensive. And may not be necessary at this time.

What you can try to do is this and it will take considerable patience on your part:

Get yourself some very thin, white Japanese Kozo paper (Tengujo is good), a small stencil brush and some archival white glue. Place your painting face down on a cushioned surface--a flat table top with blotter paper and something like glassine on it does very nicely. Since you've already tried to repair the tear with a wax mixture, you'll need to very carfully clean up the area surrounding the tear. Do this by rolling a cotton covered Q-tip dipped ( but not soaked or sopping) in a mild solvent like naphtha or mineral spirits to pick up *all* the wax. Do not soak the canvas and let it dry in between applications as the solvents can dissolve a newer paint film. If you don't do this well, the mend I'm recommending will not adhere to the canvas. (Wax is a weak adhesive which is why it isn't staying attached to the canvas. It works very well for linings, but the type we use is a mixture of pure microcrystalline waxes with special properties.)

If the tear is accessible (not directly behind a stretcher bar) do your very best to flatten the tear and realign the yarns of the canvas so that they match up. You can relax and flatten the tear with the application of a *slightly* damp piece of blotter paper placed directly on the tear with a piece of Masonite and a weight after you've tried to align the yarns. But the heat and moisture from your fingers works well to help relax the fabric, too. Next, re-weave these yarns together as best as you can. If they are too distorted or frayed, carefully clip the pieces you cannot re-weave. (And now you're not surprised your conservation friends want to charge you so much! :) )

Then using a very dilute mixture of an archival, water-based PVA white glue preferably (try not to use hide glue as it moves with environmental changes way too much), reattach the broken yarns together as best as you can. Don't let any of the ruptured yarns poke through to the front. Cover the tear with a dry piece of blotter, a small piece of wood or Masonite (that is smaller than the blotter, but larger than the tear) and allow the glue to dry. Keep replacing the blotter every few minutes so that the glue doesn't stick.

Once the glue is dry, wet cut a piece of the Japanese Kozo paper to a size a bit larger than the tear. Ideally the grain direction of the paper should run perpendicular to the direction of the tear so that the longest and strongest fibers of the paper are holding the edges together. Saturate the paper with the dilute glue mixture, but blot it a bit before application. Place the paper over the now flattened and re-woven tear and tamp it down using the small stencil brush. Use the stiffness of the brush to slightly push the long fibers of the paper away from the edges of the tear as you want to feather out the fibers a bit. Once again, place blotter, Masonite and weights on the area of the tear, changing the blotter every few minutes, until dry. Keep the weights on the tear overnight at least.

A problem with canvas is that it has plastic memory--once deformed, it wants to return to that shape, so you may eventually get a bit of a dent in that area again. Unless you have the painting lined, there's not a lot one can do about that.

If the painting were in my studio at this point, the loss created by the damage would be filled with a water-based spackle and the loss inpainted with dry pigments in a synthetic resin. You can try to repaint that area, but make sure that the cracks and losses are re-gessoed as oil paint applied directly to the canvas will cause it to rot. Because of the crushed paint caused by the damage, there will likely be a bit of a scar. You might be the only one to notice it, especially if you have a lot of texture in the paint.

Good luck to you! I wish you the best. Please let me know if you have any more questions and I'll be glad to try to help.
Sincerely,
Lorraine
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Old 09-12-03, 04:32 PM
Camilla Camilla is offline
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Thanks a lot for your thorough answer. I have a few questions, though.

First of all: What is archival glue? My guess is that "archival" means that it is of a quality that is suitable for stuff that is to be put in an archive i.e. stuff with a long shell life such as art. Is that correct?
I have some wood glue/carpenters glue from Casco. Can this be used? I don't know whether it is PVA glue or not - it doesn't say on the container.

What on earth is glassine? And what do you use as blotter paper?

How do I reweave ends that barely meet? Doesn't weaving require some excess to work with?

How dilute is a "very dilute" mixture of glue?

What is it to "wet cut" (the Japanese paper)?

I can't visualize how to "push the long fibers of the paper away from the tear". Wasn't the point that these long fibers were to join the edges?



Camilla
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Old 10-12-03, 02:45 AM
hisstah hisstah is offline
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Hi again, Camilla,

Sorry for the confusion--I always leave something out by accident. :)

Your definition of archival glue is correct. It can also be reversed fairly easily. You want to use a white glue, not a carpenter's glue, which often has hide glue in it. I don't know what name brands are available to you where you are, but you can look here at the glues advertised and might get an idea. Most of the PVA (polyvinylacetate) glues at this site would probably work fine. http://www.talas-nyc.com/

Glassine is a very smooth paper that looks a bit like waxed paper. The idea is to have a very smooth, *clean* surface to lay your painting face down upon. If you have some sheets of newsprint with maybe some rag paper underneath, you can use that. Just make sure that you layer it evenly and that there are no lumps or irregularities in the surface.

Blotter paper is used as a cushion and also as an absorber for water. It's a waterleafed paper, if I remember correctly, which means that it's not sized with gelatine and can absorb water very quickly. It's used a lot in printmaking. You might be able to use a couple of soft paper towels instead of blotter when you flatten the tear--just don't soak them too much. Blotter paper can hold minimal amounts of water easily, unlike a paper towel, which is designed to suck up the moisture.

You should dilute the glue by half with water. Sorry I wasn't more specific at first. :)

If you don't have enough yarns to reweave (wow, they must have done some serious damage) you clip the yarns to where they *can* meet other yarns--you don't want loose threads waving about. The fabric has a woof and weft that weave one into the other, up and over. Clip the ones that don't meet and make sure the ends are adhered securely to the yarns that still remain using the glue. Do this before you put the Japanese paper mend on the tear.

You wet cut Japanese paper by taking a small brush and drawing on the paper with water. You can then easily tear/cut the paper. The Japanese paper has long thin fibers that feather out from the edges when you cut it this way. You want this feathered edge to the paper--hard edges on a patch can sometimes transfer to the front of the painting, though it is unlikely to happen with this. It's just a good practice to get into. :)

When you've got the paper mend placed on the tear and pressed down into the canvas with the stencil brush, some of those long fibers can bunch up at the edges. To avoid that, you use the stiff stencil brush to stroke these fibers outward away from the tear--feather them so you don't get a lump of paper. That's what I was referring to when I mentioned that.

I forget that if you've not done this before, it's really hard to imagine. I hope this is a help to you and please do not hesitate to ask any further questions if I didn't make myself clear. Good luck!!! I sure hope this will work for you--it really should.

Sincerely,
Lorraine
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Old 11-12-03, 02:18 PM
Camilla Camilla is offline
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Thanks a lot again.
I still have trouble understandig the weaving part. When you say "weave" I imagine someting with threads going up and down intersecting with each other, which you can't really do with cut edges. Is you point, that the frayed (and hence slightly overlaping) ends of the threads are put together in an overlapping manner and glued together, and that the ends that don't meet are glued to their neighbour instead?

Camilla
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Old 11-12-03, 02:49 PM
hisstah hisstah is offline
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That's right, Camilla. Just try to put the yarns back into place as best you can. Sometimes it's impossible if they've been distorted or ruptured too badly. If some overlap, clip them so that they meet without overlapping or you'll have a lump there. Just do what you can to make the area as whole and *flat* as possible before you apply the paper mend.

Good luck! Please let me know how it goes. :)
XXXOOO
Lorraine
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Old 11-12-03, 04:35 PM
Camilla Camilla is offline
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I'm going to town tomorrow, så I'll see how many of the materials I can find. I'm not sure about the glassine. If it is what I think it is, then it is not particularly water absorbent. Well, I'll ask.

I think I will try it out on a test canvas, since it sounds like it is a procedure, where the glue might not stick to the surfaces it is suposed to, but will surely stick to all the surfaces it is not supposed to (blotting paper, masonite etc.) - at least when you've never tried it before. :grin:


I'll let you know how it's going. If you get a desperate call at 3 a.m. (that will be about 9. p.m. for you) then it's just me who managed to glue myself to the wall!


Camilla
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Old 12-12-03, 02:24 AM
hisstah hisstah is offline
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Good luck!! :grin: I think once you've tried the procedure on a scrap piece of canvas, things will make more sense and you'll feel more confident about it. It's really not that difficult.

If you can't find glassine, don't worry about it. It's not very water absorbent at all--it acts mostly as a smooth clean surface to lay your painting on so that you won't get any abrasions in the paint.

I saw some of your work posted online--very lovely and quite surreal. I liked your pieces very much! :grin: Keep up the good work!
XXXOOO
Lorraine
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Old 14-12-03, 12:57 PM
Camilla Camilla is offline
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Hi again, again!
So, now I have japanese paper. Now the glue gives rise to further questions (please let me know if you think I ask too many questions).
I checked its data sheet which stated that the glue has a pH between 5 and 6. Does this mean that it contains acid that will cause the canvas to deteriorate?

Camilla
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Old 18-12-03, 02:36 AM
hisstah hisstah is offline
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Hi Camilla,

The pH of the glue is just fine. Linen is slightly acidic anyway--if I remember correctly it's around a 6 or 5, too. Not sure what pH cotton duck is, but I wouldn't worry.

And you are *not* asking too many questions. :) Please ask away! I may not be able to get back with you right away, but I'll do my best to answer when I can.

XXXOOO
Lorraine
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