[Table of Contents] [Search]


[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

[BKARTS] The fairy dust of adhesive lay-flat bindings-Strength Testing?



OOPS I TORE OUT ONE OF YOUR PAGES!
I went on a bicycling overnight outing to beautiful Gabriola Island BC
Canada with a club I belong to and brought along the double-fan adhesive
lay-flat test book I made. I passed it around to get some more impressions.
Lot's of people said that they dislike typical mouse-trap books. One person
described how he uses different fingers of one hand to keep the book open
while he reads and eats supper. Most liked the idea of a lay-flat book. Then
one of the really tall strong guys in the group tore out one of the pages
unintentionally while playing with the book. I realized some more testing
had to be done. I had not done a "Corner Pull Test". As soon as I got home,
I did some Corner Pull Tests and found that my PVA adhesive bound lay-flat
book only required 0.15 lbs force to tear out a page with the Corner Pull
Test while the stapled, polyurethane, and thermal hot melt bound books all
pulled 1.3 lbs. My PVA adhesive bound lay-flat book had scored well on a
Page Pull Test  and other folding tests but was utterly weak on the Corner
Pull Test.

DESTRUCTIVE AND NON DESTRUCTIVE BOOK TESTS
I decided to make a list of different book tests in case I had missed some.
Some of these tests are destructive in which case a book will be destroyed
while testing, which can be used to evaluate the binding design of books
before producing them. Some tests are non destructive which can be used to
evaluate books from the production line without destroying them. Probably
only the minimum page pull test is non destructive:

   1. Page Pull Test...leaf is pulled with uniform force along its entire
length
   2. Subway Test...book doubled back so covers touch
   3. Page Flex Test...bending individual page in book 45 degrees repeatedly
   4. Tumbling Drum Test...tumbling finished book in rotating drum
   5. Corner Pull Test...pulling page at upper or lower corner only
   6. Tearing Resistance Test...strength of paper with tear started
   7. Folding Endurance Test...bending individual paper sheet repeatedly
   8. Aging Test...determine breakdown of book materials
   9. Whip Test*...book is whipped open and closed rapidly
   10. Mull Strength Test*...open book is pulled at upper or lower edge till
mull tears
   11. Cover Hinge Test*...open book is pulled at upper or lower edge till
hinge tears
   12. Paper Tensile Strength...pulling necked down paper sample with and
against the grain
   13. Paper Stiffness Test...determining how easily paper bends and in
different directions
   14. Paper Crushing Test...see how well pages and cover stock can resist
bending without creasing permanently

*not typical presently

PAGE PULL TESTS
Here are some page pull tests I did recently which I listed in a previous
message. I used a page pull tester made with a slot in the board and an
inverted pant hanger. I only made the books marked with an asterisk*. The
other books are commercially made. My PVA adhesive bound books did use
fairly tight weave bookbinding mull.

   1. Hot melt adhesive, Thermal Binding, noncoated paper, Page pull
average=6.3 lbs/inch
   2. Polyurethane adhesive, Clamped at spine single application, noncoated
paper, Page pull average=3.2 lbs/inch
   3. PVA adhesive, Double fan single application, nondiluted,  noncoated
paper, Page pull average=2.54 lbs/inch*
   4. PVA adhesive, Clamped at spine single application, nondiluted,
noncoated paper, Page pull average=2.2 lbs/inch*
   5. Polyurethane adhesive, Clamped at spine single application, coated
paper, Page pull average=2.09 lbs/inch
   6. Hot melt adhesive, Typical perfect bound, noncoated paper, Page pull
average=1.9 lbs/inch

PAPER TENSILE STRENGTH
I made a test strip with necked down area of 0.25 inches wide. Stapled
cardboard tabs with punched holes to each end. Paper is 0.004 inches thick.
Applied force with jug filled with water till the paper tore. Calculated the
combined mass of jug and water.

   1. Office Depot multipurpose paper long grain=7400 psi=29.6 lbs/inch
   2. Office Depot multipurpose paper cross grain=3557 psi=14.2 lbs/inch

CORNER PULL TESTS
In my corner pull tests I marked a 15 deg angle across one page. I stapled a
cardboard tab with punched hole onto the upper corner of the preceding page
which I pulled at the 15 degree angle till it tore visibly. Usually when the
tear started it spread quickly. All the books had non coated paper in the
20/50 lb range.

   1. Hot melt adhesive, Thermal Binding, noncoated paper, Corner pull
average=1.3 lbs
   2. Polyurethane adhesive, Clamped at spine single application, noncoated
paper, Corner pull average=1.3 lbs
   3. Folded stapled sheets, noncoated paper, Corner pull average=1.3 lbs
   4. Vinyl repair cold adhesive, Clamped at spine single application,
nondiluted,
noncoated paper, Page pull average=0.90 lbs
   5. Sewn signatures, noncoated paper, Corner pull average=0.75 lbs
   6. Hot melt adhesive, Typical perfect bound, noncoated paper, Corner pull
average=0.67 lbs
   7. PVA bookbinding adhesive, Double fan single application, nondiluted,
noncoated
paper, Corner pull average=0.15 lbs

CONCLUSIONS
   1. The PVA adhesive double-fanned lay-flat test book I made did well in
the Subway Test, the Whip Test, the Page Pull Test, but failed miserably in
the Corner Pull Test.
   2. In a strong adhesive 8.5 x 11 inch size bound book, it would take 70
lbs force to tear out a page with the Page Pull Test, but only 1.3 lbs in
the Corner Pull Test. Any book is weakest in corner tearing.
   3. Corner tearing strength does not seem to be related to the page pull
strength.
   4. In my opinion, corner tearing strength should be one of the most
important tests in destructive testing at least.
   5. The sewn binding is actually weaker in corner tearing strength than
many of the better adhesive bound books as the load is placed on a single
thread in a tiny hole which easily cuts into and tears a page.
   6. Some adhesive bound books are 50% as strong in the Page Pull Test as
the tensile strength of paper. Actually in tearing tests of these strong
adhesive bound books, the paper does often tear as well as the adhesive used
in binding due to the variable nature of the forces involved in a book
compared to a test strip.
   7. Either PVA is a very weak adhesive compared to other adhesives in
terms of corner pull strength, or the PVA I received recently is very poor
quality or defective. Either way it is what the bookbinder is using at the
moment as well. A test strip of this PVA is very flexible and reasonably
strong.

QUESTIONS
   1. If you have seen or done corner pull tests with PVA and other
adhesives, I would appreciate seeing the results.
   2. Corner Pull Tests are not mentioned very much or done it appears. Why
is this? It appears to be an important test.

Ben Wiens...applied energy scientist
Ben Wiens Energy Science Inc.
8-1200 Brunette Ave. Coquitlam BC Canada V3K1G3
E-mail: ben@benwiens.com
Energy Website: www.benwiens.com

             ***********************************************
            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>
             ***********************************************


[Subject index] [Index for current month] [Table of Contents] [Search]