Quebracho

Description

The durable wood obtained from either of two South American trees: Aspidosperma quebracho (red) or Schinopsis lorentzii (white). Quebracho wood is extremely hard, polishes well and has a spotted reddish brown appearance. It is generally stained black. Quebracho wood is used for carvings, railway sleepers, and heavy construction. The quebracho wood is high in tannins containing up to 37%. However, the extract is low in salts and acids and is usually mixed with Alum, salt, Chestnut, Hemlock, and/or Sumac. Quebracho tannin is the most important vegetable tanning agent used in the American leather industry (Lewis, 1993).

Synonyms and Related Terms

Aspidosperma quebracho (red quebracho); Schinopsis lorentzii (white quebracho); quebracho colorado; quebracho (Fr., Port.)

Physical and Chemical Properties

• Trees grow to 30-50ft (9-15 m) tall and 103 ft (0.3-1 m) wide
• Heartwood is light to medium reddish brown and color darkens on exposure to light; sapwood is pale yellow
• Grain is irregular but texture is fine and uniform
• Durability is good along with its resistance to insects
• Density = 72-78 ppcf

Working Properties

• Difficult to work because of high density and irregular grain
• High cutting resistance, as well as pronounced blunting effect on cutters.
• Dries slowly—and tends to crack, check, and warp while drying.
• Turns and finishes well, and also able to take on a high natural polish without any finishing agents.

Resources and Citations

• The Wood Database: Quebracho

• G.S.Brady, Materials Handbook, McGraw-Hill Book Co., New York, 1971 Comment: p. 648

• Richard S. Lewis, Hawley's Condensed Chemical Dictionary, Van Nostrand Reinhold, New York, 10th ed., 1993

• Hermann Kuhn, Conservation and Restoration of Works of Art and Antiquities, Butterworths, London, 1986

• F. H. Titmuss, Commercial Timbers of the World, The Technical Press Ltd., London, 1965

• Matt Roberts, Don Etherington, Bookbinding and the Conservation of Books: a Dictionary of Descriptive Terminology, U.S. Government Printing Office, Washington DC, 1982

• Random House, Webster's Encyclopedic Unabridged Dictionary of the English Language, Grammercy Book, New York, 1997

• The Merck Index, Martha Windholz (ed.), Merck Research Labs, Rahway NJ, 10th edition, 1983 Comment: entry 8213

• The American Heritage Dictionary or Encarta, via Microsoft Bookshelf 98, Microsoft Corp., 1998

• American Leather Chemists Association Glossary at www.leatherchemists.org