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Re: [BKARTS] Chiming in, Reflections on double fan binding



Here is a bit more from Rupert Evans
I agree with Peter's observations below.
If you are interested in experimenting with notches in double fan glued
bookbinding, here is a method of doing it with minimum equipment, assuming
that you have one of Peter's double fan gluing presses:

Make a top clamp for his press. Take two pieces of 1/2" or 3/4" birch plywood
or hardwood, 18 inches long, and as wide as the part of the text block which
extends above Peter's clamp. Bevel the edges of these two pieces at a ten
degree angle, so that the end view forms a parallelogram. Fasten the two
pieces together with two 5/16" x 4 inch long carriage bolts and wing nuts.
Clamp the protruding text block between these two boards. About 1/16" of the
text block should extend above the clamp.

The number of notches and their spacing is not critical, though the spacing
should be approximately the same from head to tail of the text block. However,
the depth of the notches should be uniform. Otherwise you will have a crooked
gutter. To keep the depth uniform, clamp a depth guide made of two pieces of
hardwood, about 1/4" x 1.5" x 15" long, on each side of a back saw, so that
about 1/16" of the saw teeth protrude. For a trial, these guide pieces may be
clamped on with two C (G) clamps, but for permanent use, they should be bolted
through two 1/4" diameter holes drilled in the back saw.

An earlier note suggested hammering the set out of a back saw. A much better
way is to use a new (sharp) mill file. Used flat against the side of the saw,
this will remove the set in a few seconds, without the danger of kinking the
saw with hammer blows.

I would be interested in Peter's microscopic observation of the action of the
adhesive and paper in a notch. When the book was opened flat, would the paper
split vertically below the notch?

Rupert

>===== Original Message From pete@temperproductions.com =====
>>From: Eric Alstrom
>>Maybe Peter and/or Gary can chime in too.
>
>Okay, I'll try.
>
>Regarding Ben Wiens speculation as to why double-fan binding has
>not been widely accepted:  I believe the answer to that lies in the
>ability to mechanize the process for mass production.  Hot melts
>adapt very well to a mechanized, mass producing assembly line.
>They go on quick and set up almost immediately.  Hot melts do not
>lend themselves to the fan-gluing process and cold emulsion,
>relatively slow-drying PVAs do not lend themselves well to mass
>production.  The superiority of the fan-glued binding is simply
>irrelevant.  The market demands fast, cheap books and the market
>gets fast, cheap books.
>
>The exception to this is the library binder (both big and small).  The
>nature of the library binding business is such that every book is
>potentially different from the last book and has to be handled as a
>separate book.  There is no machine that accepts vastly differing
>materials at one end and spews out bound volumes at the rate of
>thousands per hour.  This makes library binding much more labor
>intensive than edition binding.  The advantage is that the slower
>overall process easily accomodates the fan-gluing process.
>
>Regarding notching:
>
>I am going to disagree with everyone here.  I think the perceived
>effects of notching have nothing to do with the length of the glue line.
>Notching effectively alters the structure of the spine as does sawing
>the spine and gluing in strings.  If you took a piece of paper that was
>15" long (we'll say it is 2" wide)  and added a series of little accordian
>folds across the width about a 1/16th inch deep, at sufficiently close
>intervals such that the length of your "accordianed"  (for want of a
>better word) paper was now 10" long you will have approximated the
>glue line of a notched binding with a 10" spine.  This "glue line" is 15"
>(the length of our unfolded paper)  though the end to end length of the
>"spine" is now 10".
>
>Think about the accordianed folded paper in your hand.  At 15" length
>it flexed easily across the width.  With the accordian folds it is now
>much stiffer across the width.  We have corrugated our piece of paper
>and added rigidity perpendicular to the length of the paper.  We
>experience this type of structural strength everytime we use
>corrugated cardboard.  Notching effectively corrugates the spine of
>the book, adding rigidity to the spine.  This effect is further enhanced
>by the fact that the glue tends to pool in the notches essentially
>creating many small cords.  The advantage of notching over actual
>cords is that the cords remain slightly elastic, the depth of the cords
>can be less than actual string cords, and it is easy to add them at
>frequent intervals.
>
>As for the added length of the glue line increasing strength, I have my
>doubts.  A very close, magnified inspection of the inside gutter  of a
>notched binding frequently shows that with any kind of actual use of
>the book, the cord of glue in the notched area has worked itself free of
>the paper to which it is supposed to be attached.  This makes sense
>since these  PVA cords represent a salient beyond the remainder of
>the glue line which sets slightly back.  As the book opens, the opening
>force can be concentrated on the tips of the notches.  However, this
>brings us back to Gregor's statement that tests of notched bindings do
>show improved strength (though, as I believe he pointed out, notching
>is not always necessary).   So, what does notching do to add strength
>if it is not the length of the glue line?  I would say it is the added
>rigidity.
>
>To understand this we have to back up and try to understand what
>actually happens at the glue line.  When a fan-glued book is opened
>flat there is an inevitable stress where the pages and glue meet in the
>gutter.  The physics of the situation require that if you bend an object
>(the spine in this case) there is going to be compression on the
>backside of the bend (the outer side of the spine)  and tension or
>expansion on the frontside (the gutter).  By maintaining a very thinly
>built up spine you can minimize these stresses. I wrote an article
>some years ago that goes into this in detail.  (The article is posted on
>my website at  www.temperproductions.com/flexible_strength.htm).
>At the time of  my article I concluded that these stresses could be
>resolved with an "Elastic gutter" where the plasticized PVA emulsion
>simply stretched across the gutter of my thin-spined binding.  Several
>years later, with the added analytical benefit of an old dissecting
>microscope on long term loan to me from the St. Bonventure
>University biology department, I came to reject my earlier conclusions.
>With my vision enhanced by 30x magnification I saw that there was
>insufficient PVA between the pages to stretch across the void formed
>when the book fully opened. However, the bindings I designed and
>built on my earlier suppostions generally were very successful, with
>the exception of some coated papers. Somehow the stress was being
>relieved.
>
>Further observation showed that the stress of opening a book flat
>almost always leads to some structural failure.  With uncoated papers
>the structural failure is generally benign, whereas with coated papers
>the failure weakens the page attachment to the point where further
>failure is more imminent.  Uncoated papers suffer from structural
>failure of the substrate (the paper) itself. The paper will actually split
>and feather out along its length to make up the extra thickness
>required of it when the book opens flat to the gutter margin.  The bond
>between the adhesive and the paper remains intact.  Page pull
>strength remains high.  The page is essentially broken in and ready
>for continued use.
>
>Whereas substrate failure tends to be benign, adhesive failure is less
>so.  With uncoated papers   the bond between the pva and coated
>paper is stronger than the internal bonds of the paper itself.  With
>coated papers this is often not the case.  The adhesion between the
>pages fails before the internal bonds of the paper itself.  I characterize
>this generally as adhesive failure though the problem is frequently not
>the bond between the glue and the paper, but the bond between the
>coating on the paper and the paper itself.  The glue will usually
>remained attached to the coating.  The coating will simply detach from
>the paper.  Whether the adhesion fails between coating and adhesive
>or between coating and paper the effect is the same, the pages at the
>opening are left without the line of glue between the pages that gives
>fan-gluing its strength.  Page pull strength  drops off dramatically and
>failure of the page attachment is more likely.
>
>So what does this have to do with notch bindings and rigidity?  As you
>stiffen the spine you inhibit the full opening of the book.  This prevents
>the attachment between the pages from reaching a breaking point.
>With this knowledge in hand I learned that I could increase the page
>pull strength of coated papers significantly by controlling the spine (I
>have numbers but it is Saturday night and this isn't supposed to be a
>research paper) .  The amount of control needed depended on the
>drape (the flexibility) of the paper.  Conversely,  I found that I gained
>little or nothing by stiffening the spine of books with uncoated paper.
>Page pull tests (like Ben, I built my own tester) remained comparable
>for a flat-opening, uncoated-paper book and a uncoated-paper book
>with a more controlled opening.
>
>Notching is simply one means of controlling the spine.  The spine can
>be controlled in many ways, some good (notching probably falls in this
>category), some horribly destructive (remember all those perfect
>bound books that broke in your hands when you first opened them).
>But this a topic beyond my energies this evening.
>
>I'm hoping the above makes sense (it's late and I hope I'm not
>babbling).  These are my ideas and subject any to withering criticism
>anybody would like to throw at them.  I hope to get the above in
>illustrated form on my website in the not too distant future and will
>post to the list when I do.
>
>                                        Pete Jermann
>
>                                 Pete Jermann
>TeMPeR Productions
>117 South 14th St.
>Olean, NY 14760
>Tel. 716-373-9450
>Email: pete@temperproductions.com
>
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Rupert N. Evans
May 1-October 31: 101 W Windsor Rd. #4107, Urbana, IL 61802-6697;
217-337-7833
November 1-April 30: 501-391 S LaPosada Circle, Green Valley, AZ 85614; 520-648-8365
Author of Book-On-Demand Publishing
I love to print and bind books

             ***********************************************
            BOOK_ARTS-L: The listserv for all the book arts.
      For subscription information, the Archive, and other related
            resources and links go to the Book_Arts-L FAQ at:
                      <http://www.philobiblon.com>

        Archive maintained and suppported by Conservation OnLine
                    <http://palimpsest.stanford.edu>
             ***********************************************


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