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Re: [BKARTS] glue



I am sorry to contradict the author of the reply to this question, but maybe my comments will open a discussion that will benefit everyone:
Maybe I am wrong, but I don't think that the strength of a water-based adhesive has anything to do with warping or "pulling" of one material against another. It is my understanding of the adhesives and the paper materials, that it is the expansion of the paper before it is applied to the another material that is the important factor. In other words, if a paper is being glued/pasted to another sheet of paper or board, as that paper is being glued with animal glue, PVA, wheat paste, or whatever 'water-based' adhesive, that paper will expand. And when that paper is applied to another surface, even a 3/4" thick sheet of plywood*, that paper will dry and shrink, thus pulling the other material in a concave manner.
Depending on the amount of water in the adhesive, AND depending on the length of time that the paper is allowed to expand, COUPLED with the type of paper, all of these will affect a degree of 'pull' of that paper when it is adhered to another material.
* I had a 26" x 40" sheet of 3/4" plywood that was laminated on one side with "Formica". That plywood had bowed/pulled because moisture could get into the reverse, non-laminated side. To counteract that, I took a sheet of kraft paper with the grain running the right direction and used wheat paste because it holds more water that other adhesives. After the paper had thoroughly expanded by applying the paste, I pasted it again, and maybe even a third time --- I did this to insure that the paper had expanded as much as it could. That sheet was adhered to the plywood and allowed to dry. To my surprise, that pasted sheet of paper had pulled to plywood to almost flat. That plywood has been in my shop for many, many years and is still almost flat. Moral of the story: paper has a great deal of 'pulling' strength when it is fully expanded and still wet, and then adhered to a surface, and then allowed to dry.


In my opion, there are two possible alternatives to the original question --- the second might work, depending on the type of paper and circumstances:
1) The easiest solution is to use a non-water based adhesive so that the paper fibers cannot expand. The archives of this list has a number of alternatives, such as acrylic transfer adhesives from 3M that should work.
2) This next idea may work in some cases: Size the side of the paper that will be adhered with a thinned PVA; allow that paper to air dry so that it can shrink to its fullest extent. As it dries, it will start to cockle, so it may need to be placed between sheets of Reemay (spun-bonded polyester that will not stick) and under boards with a light weight for short periods of time so that the paper is somewhat flat. After the paper has fully dried, the PVA 'size' should provide a sufficient barrier to most of the water in the PVA that would be used to adhere the paper. Since the paper cannot expand very much, it should not pull the other material. Hopefully, this will work. It may even work with wheat paste, as long as you do not allow the moisture from the second pasting to get into the paper thus causing expansion again.


If anyone has a better explanation or clarification of this 'pulling' process, I would be interested in seeing that, even if it means that I will have to change my understanding of what happens.
Bill Minter



On Apr 3, 2007, at 9:39 AM, Lee Churchill wrote:


I've been happily using pva glue for some time in making hardcover
books,
but am currently trying to make a soft-cover book from handmade paper
with a
label attached. My question is this: can any of you recommend an
adhesive
that won't cause paper to warp when you glue another piece of paper to
it?

Hi Barbara,
When you say the paper is warping, what do you mean?
Because there could be a couple of issues, the first is too much water,
but it could also mean that your adhesive is too strong and when it
dries it is pulling the paper out of shape.
If it is simply that the PVA is too 'wet' there are a couple solutions,
brush on the PVA and simply wait a bit so the moisture partially absorbs
into the labels and partially evaporates then apply it. Or wheat starch
paste would work fine, just make a dry batch - say 1 part starch to 4
parts water - then brush it very thinly onto the label, giving the label
a little time to absorb some of the water, then lay it onto the cover
and gently but firmly burnish it down, I usually use my bent finger.
If the glue is too strong and is pulling the paper as it dries you need
to make a much weaker glue or paste. I would try making a very thin
paste, mix up 1:12 then thin it as you sieve until it is the thickness
of cream or less then brush it on the label with blotter underneath to
absorb water.
******************************


William Minter Bookbinding & Conservation, Inc. 4364 Woodbury Pike Woodbury, PA 16695 814-793-4020 Fax: 814-793-4045 Email: wminter@xxxxxxxxxxxxxx

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