Hi Green,

Although I took care to slowly heat it in a double boiler and kept it well below boiling it never attained a jelly-like consistency (it stayed roughly as liquid as water)

It doesnt gel unless its cold . You dont want it to gel — ive made gesso with RSG and accidentaly formed a gel by using a food processor to mix it with –what a disaster ! It wouldnt brush at all and acted like grape jelly .

After some four hours (before the glue set completely but was essentially touch dry) the canvas began to buckle and warp extensively. I have repeated my initial attempt with a stronger glue and a tightly stretched canvas (my initial attempt was with a loosely stretched canvas) but with the exact same results.

This problem has nothing to do with the strength of the glue . Its simply the hot glue shrinking the canvas .
Try :
brushing it on when its a little cooler,
or washing the canvas first ( a lotta people say this is a must anyhow but i dont do it )
or not stretching yer raw canvas so tight
or using a heavier grade of linen
or use heavier stretcher bars
or just take them off afterwards and re-stretch em .

when you stretch raw canvas you shouldnt see a whole lot of waves in the thread –indicating youve pulled it too tightly . They are sure to cause problems later . Ya have to anticipate firstly the glue size tightening the thing drum tight, then yer prime loosening it . If yer tensions are all imbalanced by stretching too tight in the first place yer bound to have pockets and loose places after everything is done .

hope thats some help …
colin

I forgot to ask how big are these canvases ? Are they big enough to require crossbraces and heavy stretchers, and if so did you use them ? Any dimension over like, 28 inches is almost sure to need heavy bars and a crossbrace … it also depends on the weight of canvas used .

Remember you can just restretch them if they warp after the glue dries — ya dont need to lay another coat . Or even prime them first, warped as they are, and then restretch.

thankyou for the replies so far…

I’ve been waiting to see what replies you get before jumping in since it wasn’t clear to me from your original post just what the problem was. Now you’ve elaborated on it and perhaps I can suggest something.

First of all, are you stretching your canvas in the recommended way – by starting at the center of each side and working outward toward each corner as you tack or staple? I think it’s important in order to get an overall uniform initial stretching.

Secondly, while I’ve not used RSG that often, when I have, as well as when I use acrylic gesso, I have always soaked the canvas or linen from both sides with a large sponge loaded with water. I find it makes whatever size or primer I’m using penetrate the fibers more fully. I’ve never had this sort of “wrinkling” problem and have never witnessed it with other artists I know who use RSG on linen (or on cotton, for that matter). Usually the problem, if it can be called that, is that the RSG tends to form a “drum tight” result with all that implies for the need to have sturdy stretcher strips that do not twist or bend under all that pressure.

Thirdly, and this one only you can answer, is the weave and weight of the linen. USUALLY, a reputable art supplier sells linens and canvas that are best suited to an artist’s uses. OTOH, buying by “price” instead of by physical description could be problematic. You don’t want the canvas or linen to tear loose at the tack or staple positions when it shrinks.

If you’re going to continue using the plates of ‘RSG’ and you have a food processor you can break it down to a powder yourself – you’ll find this will greatly improve the solubility (as it will with anything you’re trying to dissolve) and will make your life a lot easier

FWIW I wouldn’t use a hide glue for sizing if I were you as there are a number of better options available to the artist today.

Einion

sorry, i hadn’t realized this thread was so old.

I want to revive this thread, especially for the last post and question,
I have similar results, stretching two large canvasses of Claessens unprimed linnen 066. the sizes are: 100 x 120 cm and 100×170 cm.

I cut the linnen and tacked them handtight, then applied rabbitskin glue (I chose this over alternatives; for now). After tacking it is fairly tight.

It becomes drumtight after the glue is applied, dries in several hours, but the next day, it is quite loose. More loose even then when I hand stretched it….
What could have gone wrong?

The glue is 1:10 ratio, dissolved and heated to about 40-50 degrees C.
(i/e: quite warm, but not hot). I applied one coat.

That’s how RSG behaves on raw linen.

And, the problem with using rabbitskin glue is that when it begins to sag again, you can’t apply water to the back of the canvas to re-tighten it. Rabbitskin glue remains water soluble after it has dried, and will have a tendency to re-dissolve while you are trying to shrink the canvas with water.