Veneer cutting and drying properties


Material Information

Veneer cutting and drying properties tamarack
Series Title:
Report ;
Portion of title:
Physical Description:
5, 2 p. : ; 27 cm.
Forest Products Laboratory (U.S.)
USDA, Forest Service, Forest Products Laboratory
Place of Publication:
Madison, Wis
Publication Date:


Subjects / Keywords:
Veneers and veneering   ( lcsh )
Lumber -- Drying   ( lcsh )
Tamarack   ( lcsh )
bibliography   ( marcgt )
federal government publication   ( marcgt )
non-fiction   ( marcgt )


Includes bibliographical references.
General Note:
Caption title.
General Note:
"May 1961."

Record Information

Source Institution:
University of Florida
Rights Management:
All applicable rights reserved by the source institution and holding location.
Resource Identifier:
aleph - 029295919
oclc - 226379646
System ID:

Full Text
Tamarack or eastern larch (Larix laricina) (Du Roi) K. Koch (8_!)JLis a small to moderate size
softwood tree growing in the northeastern United States as far south as West Virginia, the Lake
States, Alaska, and much of Canada (1). The tree attains a diameter of I to 2 feet (6) and a
height of 50 to 70 feet above the ground. The trunk is usually straight, round and slightly taper-
ing (_).
The wood is fairly heavy, coarse grained, slivery, often spiral grained, and shows strong con-
trast between springwood and sumnmerwood (D_. The heartwood is yellowish-brown to russet-
brown and the sapwood is whitish and is narrow in width (.
Tamarack has moderate strength, stiffness, hardness, and shock resistance. The heartwood has
fair decay resistance and is difficult to treat with preservative (I1I. The wood is reported to be
comparatively difficult to ignite (13. The wood shrinks moderately, but warps and checks little
in drying (I). Kiln-drying schedules have been published by the Forest Products Laboratory (7).
The chief uses of the wood are for pulpwood, lumber for framing, boxes, crates, railroad ties,
telephone poles, fence posts, and fuel (0_.
Description of Logs Tested
Five 8-foot-long[ tamarack logs were received at the Forest Products Laboratory fromAroostook
County, Maine,!- for veneer cutting tests. They were of moderately good quality with knots being
the most common exterior defects. The logs were cut from three trees and were numbered 240,
Z41, and 242.
Based on the logs used in this study, the main defects to be avoided in the selection of tamarack
veneer logs are knots, end checks, and compression wood (6_).
A more complete description of the logs is given in table 1 .........

--Underlined numbers in parentheses refer to literature cited at end of this paper. .... --
'4rhe logs were obtained by the Northeastern Forest Experiment Station and Joseph M. Lupsha,
Utilization Forester, State of Maine Forest Service, in cooperation with the International
Paper Company and the Maine Public Service Company.


Report No. 1766-16
t Maintained at Madison 5p Wisconsin in cooperation with the University of Wisconsin

May 1961

Agriculture Madison

Preparation of Bolts and
Flitches for Veneer Cutting
Two logs, Nos. 240 and 241-2, were sawed into bolts about 4 feet long for rotary cutting. Three
logs, Nos. 241-1, 242-1, and 242-2, were sawed into flitches for flat slicing. Two flitches
were cut from log No. 241-1, but only one from each of the other logs because of their smallsize.
The bolts for rotary cutting were heated in water at 160* F. before being cut into veneer. Ex-
perience in heating veneer bolts has shown that softwood species similar to tamarack in specific
gravity, annual ring structure, and size may be heated at 160* F. without severe end checking.
Small heart checks opened up during heating of the tamarack bolts, but they were confined to the
portion of the bolt normally left as the core in rotary veneer cutting. Most of the veneer was
smooth and fairly tight. Sorne of the sapwood veneer, however, was fuzzy.
The flitches were heated in water at 180' F. before being sliced into veneer. Defects due to
heating did not appear in the flitches nor in the veneer. Most of the veneer was smooth and
fairly tight but.. again some of the sapwood veneer was fuzzy.
The approximate heating tiniest required for conditioning 8-foot tamarack bolts of various diam-
eters in water at 160' F. to insure a temperature of 120' F. at a core diameter of 6 inches are
as follows
Log diameter Heating time
(Inche s) (Hour
12 5
24 30
30 48
The approximate heating times required for conditioning 8 -foot flitches of various end dimensions
in water at 180' F. to insure a temperature of 160' F. at the flitch center are, as follows CO:
Average end dimension of flitch Heating time
(Inches) (Hour )
6 4-1/2
12 17
16 29
The data in these tabulations are based on an assumed starting temperature of 70* F. If the
wood is colder, additional heating time is required.
Veneer Cutting
Rotary Cutting
The lathe settings given in table 2 were satisfactory for cutting smooth, fairly tight veneer. The
sapwood veneer was smoother and had less shelling when cut with a horizontal nosebar opening
larger than that used for the heartwood veneer (table 2).
Most of the veneer was smooth and uniform in thickness. The knife checks were shallow in the
1/16-inch-thick veneer and moderately deep in the 1/8-inch-thick veneer. Most of the knots cut
smoothly and did not damage the edge of the lathe knife. Veneer containing compression wood
cut smoothly.

Report No. 1766-16

The slicer settings given in table 3 were suitable in most cases for cutting veneer of good quality.
On portions of the flitches from which all sapwood veneer was cut, however, the sapwood was
fuzzy and often severely shelled.
The quality and appearance of the sliced veneer was similar to that of the rotary-cut veneer.
The l/8-inch-thick veneer had slight roughness in half of each sheet (9). In general, smooth
veneer was cut when the angle between the ground face of the slicer knife and the wood rays was
less than 90* (_LO. Slightly rough veneer was cut when this angle was greater than 90'.
Veneer containing compression wood cut smoothly.
Veneer Dryring
The veneer was dried insa mechanical roller -conveyor -type dryer. Drying schedules used are
shown in table 4. Most of the veneer dried flat and smooth and had few splits or other drying
Sapwood veneer that had been cut with excessive nosebar pressure often broke apart along the
annual rings during drying. Veneer, 1/16-inch thirk, containing compression wood often buckled
severely during drying. Veneer, 1/8-inch thick, containing compression wood, usually buckled
only moderately during drying.
Shrinkage of veneer dried to between 4 and 9 percent moisture content was moderate.
Veneer Yields and Grades
Rotary-Cut Veneer
There was little loss of veneer from defects ; or roundup at the lathe as three of the four bolts
were nearly cylindrical. The actual board foot yield of veneer was about 19 percent greater than
the log scale (Scribner Decimal C).
Veneer cut 1/16-inch thick was graded (I_) for use in structural plywood. Based on the total
yield of dry veneer, an average of about 19 percent was "A" grade; 4 percent, "B" grade; 76 per-
cent, "C" grade; and I percent, "D" grade.
Rotary-cut veneer 1/8-inch thick was graded for use as box shook (14j). When this veneer was
clipped so as to obtain the maximum amount of acceptable shook, there was an average of about
73 percent acceptable shook 4 inches wide, based on the total yield of dry veneer.
Most veneer degrade was caused by knots.
Sliced Veneer
Yield measurements made on two flitches (Nos. 241-12 and 242-21) showed that about 66 percent
of the green flitch volume was recoved as dry veneer.

Report No. 1766-16

There was little loss of sliced veneer because of defects. The actual board-foot yield of veneer,
measured on one of the flitches, was about 5 percent less than the log scale.
Veneer, 1/16-inch thick, was graded for use as faces for decorative plywood. An average of
about 13 percent of this veneer was suitable for clear faces, 30 percent for knotty faces, and
57 percent for back or core grade, based on the total yield of dry veneer.
Sliced veneer, 1/8-inch thick, was graded for use as box shook (jt A There was an average of
68 percent acceptable shook when the sheets of veneer were clipped for grade, based on the total
yield of dry shook 4 inches wide.
Most veneer degrade was caused by knots.
The wet veneer developed a blue-black stain upon contact with iron or steel. The stain was
easily removed by swabbing the wood with oxalic acid
Plywood panels of good quality were made with some of the veneer. Attractive -decorative panels
were made with faces of sliced veneer, 1/16-inch thick, of both the clear and knotty grades.
The panels were five-ply with the core of ponderosa pine, 1/8-inch thick, and crossbands of
yellow-poplar, 1/24-inch thick. A phenolic film glue was used for bonding.
Sheathing-grade plywood, 1/2-inch thick, was made with five plies of rotary-cut tamarack
veneer. The core and crossbands were 1/8-inch thick and the faces and backs were 1/16-inch
thick. The plywood was made with an extended phenolic glue of the type frequently used for
interior-type, sheathing-grade plywood. These panels had a random knot and grain pattern,
much like that seen in some Douglas-fir plywood, and were fairly flat and free from checks.
Based on these limited studies, tamarack would be considered as moderately easy to glue.
The decorative plywood panels made with knotty faces were filled with a neutral-colored wood
filler. No filler was used on the panels with clear faces. The panels were lightly sanded and
then were finished with two coats of clear lacquer. The panels were readily sanded to a smooth
surface and were finished without difficulty.
Appearance and Potential Use of the Veneer
Tamarack plywood, faced with knotty or clear sliced veneer, makes attractive -decorative panel-
ing. The knots are usually small and fairly tight, and the wood has a warm yellowish-brown
color with a slight-greenish cast. Veneer containing compression wood had an orange cast with-
out the greenish tinge. Sheathing-grade plywood made with rotary-cut veneer would probably be
suitable for structural use (j). Based on its specific gravity and modulus of elasticity, tamarack
would fall into Species Group I as listed in the Commercial Standards for Western Softwood Ply-
wood (12. Rotary-cut veneer also seems suitable for box shook.

Report No. 1766-16

Literature Cited
1) Betts, H. S.
1945. Tamarack. American Woods Series. U.S. Dept. of Agri. Forest Service.
(2) Brown, H. P., Panshin, A. J., and Forsaith, C. C.
1949. Textbook of Wood Technology. Vol. 1. New York.
(3) Downs, L. E.
1950. Bleaching Wood. U.S. Forest Products Laboratory Report No. 1705.
(4) Federal Housing Administration
1958. Minimum Property Standards for One and Two Living Units. Ft1A No. 300.
U.S. Government Printing Office.
(5) Fleischer, H. 0.
1959. Heating Rates for Logs, Bolts, and Flitches to be Cut into Veneer. U.S. Forest
Products Laboratory Report No. 2149.
(6) Forest Products Laboratory
1955. Wood Handbook. U.S. Dept. of Agri. Handbook No. 72, Forest Service.
1960. Kiln Schedules and Drying Times. U.S. Forest Products Laboratory Report
No. 1900-5.
(8) Harlow, William H., and Harrar, Elwood S.
1941. Textbook of Dendrology. 2nd Ed. New York.
(9) Lutz, John F.
1952. Measuring Roughness of Rotary-Cut Veneer. The Timberman, Vol. LIII, No. 5.
1956. Effect of Wood-Structure Orientation on Smoothness of Knife-Cut Veneers.
Forest Prod. JOur. Vol. VI, No. 11.
(11) MacLean, J. D.
1952. Preservative Treatment of Wood by Pressure Methods. Agriculture Handbook
No. 40, U.S. Dept. of Agri., Forest Service.
(12) Office of Technical Services, Commodity Standard Division
1961. Western Softwood Plywood Commercial Standards CS122-60. U.S. Dept. of
(13) Prince, Robert E.
1915. Tests on the Inflammability of Untreated Wood and Of Wood Treated With Fire -
Retarding Compounds. Report of the Commission on Uses of Wood. Proc. of
the National Fire Protection Assn.
(14) Production and Marketing Administration; Poultry Branch
1951. Recommended Specifications for Standard Packs, Containers, and Packaging
Materials for Poultry and Poultry Products. Handbook 25, U.S. Dept. of

Report No. 1766-16

Table 1. --Description of tamarack logs used

Number of :L(
rings per :gra
inch :
[axi- : Mini-:
'um : mum:
10 : 5 : 3

g 1:Approx-:


Average :Average : Defects

Log : Average : Length: Average: Average: Total:

:.width of :
: sapwood:

eccen- :num-:
tricity :bet :
of pith :of :
: M
In. :
0.6 : 66 :
1.0 : 65 :
.5 : 58 :
.4 : 69 :

imate :specific, : green :
:log g gravi ty- moisture :
scale ::content-:
(S crib -- - - ------------

No. :diameter in-:
:side bark:

In. :
1.0 :
1.5 :
1. 3:
.8 :
1.0 :

: - - - - - - -
:end :end:

: In. :
240 :16.6:
241-1: 14.6:
241-2: 14.0:
242-1: 10.5:
242-2: 9.6:

: ner : Sap-
:Dec. C): wood
:Bd. ft.:
:90 :0. 40

:Heart-: Sap-
:wood :wood

:wood :
:58 :Many knots on all
: : faces, split, over-
: : grown injury, fluted
: : butt, much taper
:47 :Many knots on two
: : faces
: 48 :Many knots on three
: : faces
:66 :Knots on three faces
:63 :Few knots on all
: : faces

In. :Ft. -in.:
20.9 :8-3 :
18.6 : 8-6 :
14.8 :8-4 :
11.9 : 8-6 :
10.8 : 8-5 :

: cent
: 175
: 157
: 169
: 1 34

:0. 48

13 :
25 :

4 :
5 :

70 :
60 :
30 :
30 :



-'Grade specifications for eastern white pine logs --Northeastern Timber

Salvage Adrministration.

The Log Grade Specification was

established by the U.S. Forest Service for use in the purchase of logs during the New England Hurricane Emergency Project
"-Based on green volume and ovendry weight.
"-Based on ovendry weight.

Table 2. --Settings used to rotary cut tamarack veneer
Veneer :Type of : Lathe knife Pressure bar
thickness : w ood -- - - - - -------------------------------.... .... ...
::Bevel : Angle :Bevel :Vertical llorizontal
: : : openingg : opening
In. ::Deg. Deg -Min. D In__. In.
1/16 :Sapwood 21l 90-15 : 75 : 0.014 : 0.061
(0.0625) :Heartwood : 1 : 90-15 : 75 : .014 : .057
1/8 :Sapwood : 21 : 89-50 : 75 : .Z8 : 123
(0.125) :Heartwood : Zl 1 89-50 : 5 : .028 : .115

Table 3. --Settings used to slice tamarack veneer

Table 4. --Drying schedules used for tamarack veneer

Report No. 1766-16

Veneer : Slicer knife :Pressure bar
thickness -- - - - - - - - - - - - -
:Bevel : Angle :Bevel :Vertical :Horizontal
: :: : opening : opening
In., : Deg. :Deg. -Min. Deg. : In. : In_.
1/16 : 22 : 90-25 : 78 : 0. 030 : 0. 057
1/8 : 22 : 90-30 : 78 : .030 : .115
(0.125S) :::

Veneer :

Type of :Drying :Drying :Average:
wood :temperature: time :dry :
: : -moisture:
: : : content:

:Average shrinkage
:- - - - - -
:Radial :Tangential

Range of
of dry

- -: : ...- -. ..-- -- : --- .. . ..- : - :- -- - - -- -


: 5.3
: 8.1
: 6.5
: 5.3
: 8.5
: 14.8
: 13.4
: 12.3



4. 9-5. 8:
4. 3-11. 7:
4.8-7.1 :
3.6-8.9 :
5. 8-11. 4:
11.O0-19. 2:
12. 5-17. 0:
10. 1-13. 8:

Percent :Percent
3.3 : 7.4
4.9 : 6.0
4.8 : 4.9
5.2 : 7.9
2. 6 : 5.0
3.7 : 3.5
1.7 : 3.0
2. 7 2 .8

(0. 06Z5)
(0. 06Z5)
(0. lZ5)

: .... do .....:
:Harwood :
: .... do .....:

1/8 :Heartwood:
(0. 125) : .... do .....:

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