Moisture content and storage affect strength of nailed wood boxes

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Material Information

Title:
Moisture content and storage affect strength of nailed wood boxes
Series Title:
Technical note ;
Physical Description:
1 p. : ; 21 cm.
Language:
English
Creator:
Forest Products Laboratory (U.S.)
Publisher:
U.S. Dept. of Agriculture, Forest Service, Forest Products Laboratory
Place of Publication:
Madison, Wis
Publication Date:
Edition:
Rev. June 1953.

Subjects

Subjects / Keywords:
Lumber -- Moisture   ( lcsh )
Wooden boxes -- Evaluation   ( lcsh )
Genre:
federal government publication   ( marcgt )
non-fiction   ( marcgt )

Notes

Additional Physical Form:
Also available on the World Wide Web.
General Note:
Caption title.

Record Information

Source Institution:
University of Florida
Rights Management:
All applicable rights reserved by the source institution and holding location.
Resource Identifier:
aleph - 029721219
oclc - 60933808
Classification:
lcc - TA419 .U45 no.128 rev.1953
System ID:
AA00025015:00001

Full Text

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TECHNICAL NOTE NUMBER 128
UNITED STATES DEPARTMENT OF AGRICULTURE FOREST SERVICE
FOREST PRODUCTS LABORATORY
MADISON 5. WISCONSIN TJune 1953
______________________________U N IV Q F _L |IR ~ --
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*'iiJ i I N I
MOISTURE CONTENT AND TOILAGE AFFF~r.C/
STRENGTH OF NAILED PVOOD BOXES
U S. DEPOSITORY

Of two boxes made exactly alike from the same grade and thickness of
lumber, one may stand ten times as much rough handling as the other,
because of difference in themoisture content of thelumber or adiffer-
ence in subsequent storage conditions. Tests made at the Forest Prod-
ucts Laboratory, Madison, Wis., show that only when a box is to be
used for an extremely short time immediately after manufacture is the
proper seasoning of the lumber unimportant.

Within a week after manufacture a box made of green lumber suffers a
marked reduction in strength. As the wood dries, the nails lose their
grip. The fibers which are bent down along the nail shrink away from
it in the direction of the end grain, the direction in which it was most
firmly held, leaving the nail held only by two sides. Under suchcircum-
Sstances the weaving action during transportation alone will readily cause
the nails to work loose and even come out of the box. Boxes made of
greenlumber at the Laboratory and kept for a year indry storage tested
only about one-sixth as strong as similarly-made boxes tested at the
time of manufacture.

If abox is made of dry wood and then subjected to alternate wettings and
dryings, through cold storage or exposure to weather, the nails will be
loosened just the same as in green lumber. Boxes made up from dry
lumber were kept for two weeks in damp storage and then for two weeks
in dry storage. After this treatment the boxes withstood only one-tenth
as much rough handling as those made of air-dry lumber which had not
been subjected to adverse storage conditions.

A box made of lumber in the proper moisture condition will stand ordi-
nary storage without any appreciable loss in the holding power of the
nails. The best results are, therefore, obtained when the lumber is
seasoned in accordance with the atmospheric conditions which the box
will encounter in service. If it is impossible to forecast thcse condi-
tions, it is advisable to use thoroughly air-dry lumber, which contains
from 12 to 18 percent moisture.


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