November 24, 2020

#08-014: Plywood

Veneer being peeled from a log

Note: Many of the building materials that we use today--lumber, bricks, tile, and even concrete--have been used for millennia. But one very "modern" material commonly used today (in addition to plastic!) is the humble product known as plywood.

Get Ready: Look around you. Can you see anything that might have been made from plywood? How about the other materials mentioned--lumber, bricks, tile, and concrete?

How is plywood made?

Imagine a log (called a "peeler") placed along a long blade and slowly turned, so that it is thin-sliced into a sheet of fairly flexible material (much like a piece of paper towel being taken from a roll). Now lay that piece down and coat it with glue, and place on it another sheet, but this time with the grain perpendicular to that of the first sheet. Do it again, following the grain of the first sheet, and so on. After several layers, you will have a sheet of wood made of several "plies" (hence the name plywood) that is stronger than a piece of lumber of comparable thickness, but with a modicum of flexibility that actually enhances its usefulness. It is then dried under pressure and heat, and "graded" according to the quality of the materials.

Lamination was known to the ancient Egyptians and Greeks, but machines for the production of the material as we know it were first patented in England in 1797 by one Samuel Bentham, a mechanical engineer and naval architect. His plywood was to be used in shipbuilding, where it could be curved to the ribs in the hull of a ship. (Bentham, by the way, was brother to the famous Utilitarian philosopher Jeremy Bentham, who defined the most moral behavior as that which led to "the greatest happiness of the greatest number [of people].")

Around a half-century after Samuel Bentham, another inventor named Immanuel Nobel (father of Alfred Nobel, who invented dynamite, among other things, and left his money to be given out as the annual Nobel Prizes) improved on Bentham's designs and invented the rotary lathe, a machine for turning wood in the way I described above.

Another benefit of plywood is that, when it will be used in fine woodworking such as tabletops or cabinetry, quality veneers can be used for the outer layers, and cheaper materials (including those with cracks and voids) can be used for the inner plies. This gives a high-quality appearance at a lower cost.


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Practice: Match the term to its definition below:

  1. enhances
  2. flexibility
  3. graded
  4. hence
  5. humble
  6. millennia
  7. modicum
  8. naval architect
  9. patented

  1. small amount
  2. improves; makes better
  3. ability to bend
  4. one who designs ships etc.
  5. empty spaces
  6. periods of 1,000 years
  7. modest; insignificant 
  8. thus; therefore
  9. assigned a value
  10. protected by law as one's own

Answers are in the first comment below.

Submitted to the Shenzhen Daily for November 24, 2020

1 comment:

  1. Answers to the Practice: 1. b; 2. c; 3. i; 4. h; 5. g; 6. f; 7. a; 8. d; 9. j; 10. e