STRENGTH OF ALUMINUM LAP JOINTS
AT ELEVATED TEMPERATURES
(Tests Conducted Immediately After the
Temperature Was Reached)
lat&rmaaAeRAPievietued-alid–Pea44irmed
May 454
INFORM, N
'AND
ED
962
LOAN COPY
Please return to:
Wood Engineering Research
Forest Products Laboratory
Madison, Wisconsin, 53706
This Report is One of a Series
Issued in Cooperation with
All2 FORCE-NAVY-CIVIL SUBCOMMITTEE
on
AIRCRAFT DESIGN CRITERIA
Under the Supervision of the
AIRCRAFT COMMITTEE
of the
MUNITIONS !BOARD
No. 1808
UNITED STATES DEPARTMENT OF AGRICULTURE
FOREST SERVICE
FOREST PRODUCTS LABORATORY
Madison 5,Wisconsin
In Cooperation with the University of Wisconsin
STRENGTH OF ALUMINUM LAP JOINTS AT ELEVATED TEMPERATURES1
(Tests Conducted Immediately After the Temperature Was Reached)
By
EDWARD W. KUENZI, Engineer
Summa r y
Tests were performed on lap-joint specimens of clad 24S-T3 aluminum
alloy bonded with nine different adhesives. Si:: of the adhesives were
cured under three different conditions, and three were cured under only one
condition. The tests showed that at elevated temperatures, the highest
strengths of the lap joints tested were obtained with a high-temperature. , setting phenol-resin -- synthetic-rubber adhesive. The highest strengths
of lap joints tested at room temperature were obtained with a hightemperature-setting modified-phenol-polyvinyl butyral adhesive. No specific
conclusions could be reached on the effect of curing conditions, except
that adhesives cured at the intermediate temperature usually produced joints
that had strength values between those obtained with adhesives cured at low
and high temperatures.
Introduction
Many uses l of , aluminum'sheets, particularly when used as'facings of
sandwich construction, require special methods of joining the facings of
adjacent panels or of joining the panels to attachment fittings. In using
sandwich constructions for aircraft it is desirable to use joints that have
a smooth surface. The use of bolts or rivets may not be possible, because
of the weakness of the core material. The advent of synthetic adhesives
has made it possible to bond metals together under comparatively low temperatures and pressures. Although a great many structures incorporating these
adhesives have performed satisfactorily under ordinary conditions, little is
known about their performance at elevated temperatures, such as may occur
at high speeds or in torrid climates. The purpose of the tests was to
determine the behavior at elevated temperatures of adhesives used in lap
1
-This
progress report is one of a series prepared and distributed by the
Forest Products Laboratory under U. S. Navy, Bureau of Aeronautics Order
No..NBA-PO-NAer 00619 Amendment No. 2, and U. S. Air Force No. USAF-PO(33-038)48-41-E. Results here reported are preliminary and may be
revised as additional data become available. This report Baas originally
published December 194,,.
-1-
Agriculture-Madison
Rept. No. 1808
joints for study in conjunction with the results of elevated temperature
tests on sandwich constructions employing the same adhesives.
Several of the adhesives(25, 30A, Gnd 35)used in this study were also
used to bond facings to cores in the study "Effect of Elevated Temperatures
on the Strengths of Small Specimens of Sandwich Construction of the Aircraft
Type," Forest Products Laboratory Report No. 1804.
Specimens and Methods of Testing
5
Plates of clad 243-T3 aluminum alloy by 8 inches and 0.064 inch
thick were joined with a 1/2-inch lap joint placed so that the direction of
the shear to be placed on the joint would be parallel to the rolling direction of the sheet. Prior to bonding, the surfaces to be joined were
cleaned and etched in a sulfuric-acid -- sodium-dichromate bath (10 parts
by weight of concentrated sulfuric acid, 1 part of sodium dichromate, and
30 parts of water) for 5 minutes at 140° to 160° F. After the sheets were
rinsed-and dried, the adhesive was applied and the panels were placed
between. 1/16-inch rubber pads in a press.
Nine adhesives were tested. Of these, six were cured under three
different conditions of time, temperature, and pressure in-forming the bond.
These six adhesives and the curing temperatures and pressures used with
each, were as follows:
Adhesive 25 -- A high-temperature-setting formulation of thermosetting resin _nd synthetic rubber.
Cured 60 minutes at 300° F. at 250 pounds per square inch.
Cured 25 minutes at 350° F. at 250 pounds per square inch.
Cured 25 minutes at 400° F. at 250 pounds per square inch.
This resin cured at the above intermediate condition was used as a.
primary adhesive on the aluminum for the facing-to-core bonds of sandwich
constructions having aluminum facings on balsa and on cellular cellulose
acetate core materials for the study reported in Forest Products Laboratory
Report No. 1804.
Adhesive 30A -- An intermediate-temperature-setting acid-catalyzed
Phenol resin. (Used in conjunction with Adhesive
25.)
Cured 60 minutes at 225° F. at 250 pounds per square inch.
Cured 30 minutes at 250° F. at 250 pounds per square inch.
Cured 15 minutes at 275° F. at 250 pounds per square inch.
This resin cured at the above intermediate condition was used as a
secondary adhesive for the facing-to-core bonds of sandwich constructions
having aluminum facings on balsa and on cellular cellulose acetate core
materials for the study reported in Forest Prod4cts Laboratory Report No.
1804.
Rept. No. 1808 -2-
Adhesive 42 -- A high-temperature-setting formulation of thermoplastic
and thermosetting resins.
Precured in open assembly 45 miiiiiterst 200° F. Cured 90 minutes
at 250° F. at 150 pounds per square inch.
Precured in open assembly 45 minutes at 200° F. Cured 30 minutes
at 300° F. at 150 pounds pet square indh.
Precured in open assembly 45 minutes at 200° F. Cured 10 minutes
at 350° F. at 150 pounds per square inch.
Adhesive 35 -- A commercial high-temperature-setting modified phenolpolyvinyl butyral formulation.
Preoured in open assembly 45 minutes at 200° F. Precured in
closed assembly 15 minutes at 250° F. Cured 225 minutes at
250° F. at 250 pounds per square inch,
Precured-in open assembly 45 minutes at 200° F. Precured in
closed assembly 9 minutes at 300° F. Cured 15 minutes at
3000 F. at 250 pounds per square inch.
Precured in open assembly 45 minutes at 200° F. Precured in
closed assembly 3 minutes at 350° F. Cured 5 minutes at
350° F. at 250 pounds per square inch.
This resin cured at the above intermediate condition was used for
facing-to-core bonds of sandwich constructions having aluminum facings on
cotton cloth and aluminum honeycomb core materials for the study reported
in Forest Products Laboratory Report No. 1804.
Adhesive 34 -- A high-temperature-setting, two-component resin with
a thermosetting liquid and a thermoplastic powder.
Cured 60 minutes at 250° F. at 250 pounds per square inch.
Cured 10 minutes at 300° F. at 250 pounds per square inch.
Cured 10 minutes at 350° F. at 250 pounds per square inch.
Adhesive 44 -- A high-temperature-setting formulation of thermoplastic and thermosetting resins.
Cured 90 minutes at 250° F. at 250 pounds per square inch.
Cured 25 minutes at 300° F. at 250 pounds per square inch.
Cured 15 minutes at 350° F. at 250 pounds per square inch.
The three following adhesives1 were cured under only one condition,
as follows:
Adhesive ma94 -- A laboratory-formulated high-temperature-setting
phenol-butyral resin.
Precured in open assembly 20 minutes at 200° F. Cured 20
minutes at 320° F. at 250 pounds per square inch.
-These experimental adhesive formulations were developed at the Forest
Products Laboratory in cooperation with the Navy Department, Bureau of
Aeronautics.
Rept. No. 1808
3_
.
.
Adhesive M471 -- A laboratOrY40ithal,ated, intermediate-temperaturesetting resorcinol-butyral resin.
Preaured in open assembly 10:minutee at 200 °' F. 'Cured 30
minutes at 240° F. at,250 • ponnds per square inch.
Adhesive M487•-- klábbratoryfOrmulated room-teMperature-isettingbutyral resin.
Oared 24 hears: at 75° F.' at 250-pounds per square inch. Seasoned
10 days in an atmosphere at 30 percent relative humidity at''
80° F.
Six panels were made with each adhesive and for each curing condition.
Six specimens 1 inch wide and 9-1/2 inches long were cut from each panel
with a band saw. One specimen from each panel was designated to be tested
at one of the following temperatures: 75° F. (23.9° C.), 160° F. (71.1° C.),
250° F. (121.1° C.), 350° F. (176.7° C.), 450° F. (232.2° C.), and 600° F.
(315.6° C.). Holea 3/8 inch in diameter were drilled 3/4 inch from each end
of the specimens.
Specimens were tested in an electric oven heated to the desired
temperature. The electric oven was placed between the loading platens of a
hydraulic testing machine. The specimen was loaded by means of 5/16-inchdiameter pins . placed through the 3/8-inch holes in the aluminum. The oversize hole was chosen to permit rapid insertion of the pine. Specimens
tested at 75° F. were held in self-alining wedge grips because the bearing
strength of the sheets at the pins was not great enough to fail the specimens
in some of:the stronger lap joints.
The load was applied . at a rate of 600 pounds per minute until failure
occurred. Loading was begun about 1 minute after , a thermocouple clipped to
the lap joint had indicated the desired temperature was reached. Each
specimen was placed in the oven only at the time of test. No specimens were
heated prior to the necessary testing exposure. The stronger specimens were
tested with the capacity of the testing machine adjusted to 2,500 pounds.
The loads of the weaker specimens such as those tested at 450° F. or 600° F.
were measured by means of an air cell of 200-pound capacity attached to the
movable head of the testing machine.
The amount of adhesion failure, estimated as the percentage of the
area of adhesive not adhering to the metal, was obtained by a visual examination of the failed portion of each specimen. Failures were either of
the adhesion or cohesion type or combinations of both. Thus, if a failure
was described . as 10 percent adhesion,-the joint failed because of 10 percent
adhesion and 90 percent cohesion failure. It was often difficult to ascertain the true nature of the failure.
The length and width of each joint was:rileasured to the noaroet 0,01
inch after failure.
Rept. No. 1808
-4-
Presentation of Test Results
The strengths of the lap joints are presented as shearing strengths
in pounds per square inch. This was done primarily to adjust the values to
a common base by dividing the load by the area of the lap joint, because
the dimensions of the lap joint were slightly different for each specimen.
The stress distributions in the lap joints probably were not uniform, as
the above mentioned computations would assume.2 Since the elastic properties
of the adhesives and the thicknesses of the adhesives were not determined,
further theoretical analysis was impossible.
The shearing strengths and the percentage of adhesion failures are
jmen in tables 1 through 7, and average values of six specimens taken from
six different panels are plotted against the temperatures of test in figures
1 through 10. The, values used to compute the averages showed very little
scatter.
-
Conclusions
All the adhesives used showed a definite decline in strength as the
temperature at the time of testing was increased.
The highest strengths of the lap joints tested at elevated temperatures were obtained with a high-temperature-setting formulation of thermosetting resin and synthetic . rubber (adhesive 25).
The highest strengths of lap joints tested at room temperature were
obtained with a high-temperature-setting formulation of thermoplastic and
thermosetting resins (adhesive 35).
Adhesives cured at intermediate temperatures usually produced joints
that had strength values between those obtained with adhesives cured at
high or low temperatures. Performance at the higher testing temperatures
was little affected by different curing conditions.
The percentage of adhesive failure increased to 100 percent as the
formulation of thermosetting resin and synthetic rubber adhesives.
No definite trend was exhibited by values of the percentage of adhesion failure observed for lap joints bonded with modified phenol-polyvinyl
butyral-resin, phenol-butyral-resin, or resorcinol-butyral-resin adhesives.
A comparison may be made between the behavior of sandwich constructions at elevated temperatures (see report 1804) and the behavior of lap
3
"The Stresses in Cemented Joints," by I.I. Goland and E. Reissner, Journal
of Applied Mechanics, Vol. II, No. 1, March 1944.
Rept. No. 1808
-5-
joints made with the same adhesive. - The reduction in strength of the lap
joint specimens bonded with adhesives 25 and 3CA was gradual as the temperature was increased (fig. 2).. The strengths of sandwich constructions of
aluminum on balsa or cellular cellulose acetate bonded with this same adhesive
also exhibited a gradual downward trend as the temperature was increased. The
strength of lap, joints , bonded with •adhePive 35 showed en abrupt drop at 250° F.
(fig. 4). Similarly the strengths of sandwich constructions of aluminum on
aluminum or cotton cloth honeycomb, particularly for the aluminum honeycomb,
showed abrupt drops at about 250 . F. This adhesive was also used to bond
the loading blocks to the sandwich: constructions and therefore the predominance of failures between loading block and facings at temperatures above
250° F. can also be attributed to the quality of the adhesive as measured
by the lap-joint tests. Thue-the , behavior of sandwich constructions at
elevated temperatures, provided that deterioration does not take place in
the facings or cores, may be predicted by studying the behavior of lap joints
using the same adhesives.
Rept. No. 1808
-6-
••
^s.
0
LO
t
LO
.
..
•
0
«
o
r4
4 r4 r4
r4
in
r4 r4 r4 e4 -4
4.4
••
••
•
444
•
4.4 r4 r4 r1 r4
8 8 8 8 84 8 8
8 1-48 r481. 8 8 8 8
8 8 8 8 8 8 8
•
4 4
4 4
MD 00 00
0.
•• •• 06
MO ••
06
00 Mb 00
06
00 00 00
ppp pppp
.4
0 •
43 •
• 14
t
••
•• •
.4 I.
to
C)
o o o o o o
r4 r4 6•••1 1-1
k
4D
413
00 MI MD 00 06 .
4.
▪
•
0 • al
ID 1.•
.44 4204
CO 0
so ••
- •
•
4,
•
s
°
4:b
I
O
4
lit
Mb
a•
Mb
••
ro:
•
••
0
•0 •• •• so •• a.
U
•
cr
0
os •• o• •• so ••
000000
ri r••n a%
r4 r4 r4 r4 4.4 r4
c,
0
▪
R .
00 00
1.1 r.1 tr% 1
00.0n
1.1 P11.-7
•••0
00 00 •• 00 00 00
O
e4
G
C
.
0
.
0. 00 .00 00 .
sagtR g R
•
;EI ....
Pi ,1 .4•
t•1
1,
0 S4
A 4A
Cli 10 t
t
.4 0
13
0
en
Pm
1
00 00 GO 00
00
9.,
C
1"--
•n•
MD 00 00 Mb 00
MD
F.
•a
0 ....,.
Ow 06 00 Mk MP Mb
N-
MD
82Rsg54.
I.", 0 0.. 0 N 0
r1
1,10.1 CU CU 0 Ph ...-k
.......
.0
••••••
r4
e4
0 r4 r4 r4 r4 r4 r4
r4 r4 r4 r4 r4 r4
01
.11 . 00 00
OD
00
..
0
00 Mb Mb Mb MD 00
••
K
0000000
- ... .. .. .. ..«
..
P:
.. .. ••• .. .. ..
40
..
,..:
o
0
0
0
00
0o
...-,,,
..-,.-t
o tr.,
r4
•• .. .. •• .. ..
MD
...., o,, g 9,9 o fa 8 ,
R.Nfi3)
8RR
R28R-ER
R .0W MO
In Fil
L..0 CU .?
.1
.1
.-CO
00
00
P
•
• • 1%
. .P-- ...D
..a-f4 t.0......
....... . ., . . CIPTh
•
.
M
,e,.
0 .0'
•0
•
▪
V t 0
•
...
'd-9.
0000000
r4 r4 r4 r4 r4 r4
4.4
•• 00 •• toe ••
••
00
-•4
44 I P4
.. .. I., . .
Mi.
R
O
'CI
tO
•0.
$1
•
0
r4 4 4 4 4 r4 r4 r4
t-1
••• •• No of. ••
•••
Mb
0
•11
•
0
..
g
.. .. ...
.. .. ..
-i
P
. .
0
0 0 0 0 0 0
1.-lO
a DO In u% 00
O.1 ..l• u-‘..i- 1', r4
r"
a a a a or or a
.
Oa 00 0 6 •• •• 00
00
F.
g
7 ....
..
0
r4 r4 .-1 r4 r4 r4
r4
•• •• •• •• •• ••
••
0 C RORR20
.0
,D
1..
.
4 .. ..
- ... ..
04 R- :I• n R 41 -9 g,
,I W 0.4 0 CO pi
.......•
CU CV CU CU r4 CU CU
MD 00 Oa MD 00 MD
41
0▪
I al
IL
1-1
0
cr,
i t-1 1 • ',0
..0 0 0 0 0 0 0 0 C‘J
000000
•
1•,^r
o
0
at
1.1
s
CO I'
1.
F.
11100000 CkJ q 000000 C+ 0 4.4
000000
6-1 r4 4.4
,I
c
to
to
A
•
C.)
0D
'
O
•• MD
II:
a.*
.0
am es oar so •• ••
..r.
P. C.:
DO ,I I
011.-• OD 1--- 00 1.0
00
o
69
c.)
k
I
.4
•
a,
00
ori Q
CU
s- 0
.9. 8 E
" tO 111
g'3' g am
..
r•I
i..1
0000
Oo 00 MO 00 MP M.
00
0
..101
. el
•• ..
MI
•• ••
N
--.
••1 Cu
E '
.r. .5'
• 0
2. +2•
.
00 . Oa •• Mb MI
.4' .4
o 0 0 0 0 0
CU ,, r•-,-s .d
-,
..I.1'
0.1 el
4
.0
-
••
••
u-,
•-, 41 51 ^4.
4
t• i•
4
g I: O4
0
00
Mb
IMO
oo ••
00
o 0 ..,
tr.° 0 o•-I I-1
W
0 •4 0
g
00 00 00 MD
s..--
0 0 0 0•--CU
1s-30001 0 0 0
.Wi 01 ti 0 CT 01 ON R
..# P.
14 4
... ..
..
.7. .0'
Ila
Mb •• • ••
•
•• .•
4.
0
• ...40;
40
II:
••
0000000
0 0 0 0Ca'N0 0 0
1111il Ill
0 0 0 0 0 0 0
11%4' LC
.1'
4111)
Mb
I.
0
•• .• ••
••
0,,,,o
r,cg
110.......
W 00 u--, o ../. 1.. r4 r4 rl r4 CV rl
r4
MI AN 00 00 •• 00
MD
141
•
s.0o
00 60
De 1 •
•
f•
•• • • 00 00 M 0 e•
SRV411°
0 0 0 0 0 0 0
OD 00 00 60 00 ••
00
000000
•-•
el CO
e•N P.te-lVDr.4*
sc.,
LC\
l•
.......
441 1,1 141 MP,/ 141
CO 00 00 •• 00 dm
MP MD M. 00 Mb Mb
MP
•• •• ••
••
2 8 2•••1 g\
0.70; a A:W.4'
Pr% MM 141 CU
•
or
••
1
Gr4
13 •
0•0
g. a
t
r4
4.♦ 11. 144 1,0
N 0.1. ► 11110
4
4-1 CU
ICMD
.4
tet...1. IMO
•
.4
P
• n
to
0
•
ED
r-I
191
4
0
%JD
0.0 A
.
.•
O 4a.•
•-I 410
--4
F. 0
a)
lc,
Eu
W 1.
4 ...A.
p.
I.-
CA,
CO
••
00
00
•• ••
SO 00 00 00
00
ca
O. 00 Mb
•• •••
Mb
0
00 CM 1,- 11%3
,S 0 0 o
••
Mb
0000011-1 CU
On OS 00 00 MI
CO
00000ln
to 10
•• •• .. •• •• ••
0
01
•• w •• ••
OA
Ma MD
•• .... ••
.•
k
K1
000000 0 00
10
0
•• •• •• •• oo es
1:•
.. .. - - - -
•• •• •• .. •• ..
••
..
0 C) C) 0 C) C) C)
01
eu
000000 0
CO f•P";110 kla 0 r•-% 6-1
ko I11 Ls-.
4)
••
I
CU
..
0 0
0 0 0 ..
04
•
.17
•
0
• • •
•
-I,
1/
Pr:
5)
713
A.
0
e
El
G
lO
921.
00 SO o•
0
0 0 0 0 0
aNk.0 L'143 10 111 1.1%
1/40
FrE
Ers,
0
00000
0
go. also-
•• •• •• • • se •• ••
2:0„
14
•• •• GO •• ••
1
0 0 C3 C3 0 C3 C)
I-4 6-4
••
.•
022000
fv
0
se 0
ir•
F0P-&
.5;8S' 00 Vs
ED I,- 11"\\O f••••
00 SO Mb SO 00 00
0. in 0 5-1lti rl
A' .4'
•
if•
00
0 0 0 0 0 0 0
00 •• •• 00 MP SO
00
••
ion'
0 0 0 0 0 0 0
00 el It) u. A.-4
00 MD •• 00 00 00
00
0 0 0 0 0
RiVi),R,g5',
8
00 10
LC`i
0 0 0 0 0 0 0 Cid
.0
• 0 40 0 •
r4 r4 r4 r4 r4
r••n
a
r4
•• •-• • • ••
R.°-4R.90°
0
00000
0
ea
• 0
0
4-4 4 4 4 -1 r4 4-4 r-I
.
•• .• • -- ••
0•
00
•• •• •• .•
•
•• ••
OS •0 •0 0• Mb
0 C) C) 0 C) 0 C)
z
00
..S.
I--
U
OS •• 00 00 00 OS
••
•••
0
C)
0
so
I.-- o .cio g g Foa .g. ii...N
a
4.1
9
.6
0EI
.• .. •• •• •• ••
01
'11
0:1
tO A
SI
0
, 1 co 1°O
000000 o a 8g3agg o ;11 R000go
..1 'Co ..•
I°•-1°O 1°0\ 0 ...I
0
10 .14- M1'1 .4
•
00 P-e-‘
0 l.0 It.
• 1/40 \C) 111.? 111.7
013 00
W
1344
PI4
1c
01 Ss
A ...,
0,
•
•
•
01 111
LC•
O
..
o
ED
0 0 Q 0
0 0 0 0 p00
0 0 0 0 L.c
00
a
CO (ti rl A U% EC
0 l'...- r•4 LC10 1,0 0
in rn tn tn
In rn PA'N
al .4 111,7 .7L11111 .4.a
F
I.
00
0
0
A.`" °K,
••
00 00 00 GM 00 MS
in
CV
CV
in r-1 111 CV r4 to
.0
.c1
0
0
0
O
-4-:
..0
.•
.. •• .. •• •• •n•
co
0
0 0 . . 0 2 Ma 2 0 2R 0 o
.. .. .. - .. -
ul
MD
SO SO 00 MD 00
0
0 0 0 0 0 0
N1.13 In\ CO 121 141 A'
0 0 0 0 0 0
LC10.1 LC1 141,1- .a.
ad
.0
i• rAl
0
DI
0
.
r.2
o.) ,--1
a..
A ..-I
a,
4
••
..
0
r4
1-4
00
LI:
1:. I.M.
1-I f•
0000tno to
W p 0
O -p 0
1...
LC1
ri NE.", WE r•4 l0 CV
t
..t . v
.0
41, id
4-1
•• •• •
•.• •• •• •• •• ••
••
• 0+
LC1
N 4
• •F
n. 40 .1 5 0 0 0 0 0 0 0
f• U
A' ON r.- 00 f-I
•0- .t \0.7
U1^7
in
-1- A- .4- 10.7
w
W
t5
O '1.I'
Oy
A -1-,
L.
r.0 w
0
O-1
we • •
••
8
888888
r4
r4 r4 r4 r4
888888
8
ri r4 .-4 r4 r4
r'1
888888 8
A$4
.
a
r4
..
• ••
r4 01,7 11110
MD OS 00 00
O r4 0 0 WI es
ea
• 0
r4 r4 r4 r4 r4 r4
Mb
0
r4
CU °
Wt.°. O
O g
A. 4v
I's
N a CV.
g
Crs
a)
P a)
"ea-l 1-1
o
i 'el
a*
al
o%° 8
C)
t•
Pe
.. ..
4.0
0 eaA
.4 40 el
t0 2k •
.0 a. A.
P.
V) ta
to
R°I Ogg?i1
00 •• 00 00 60 HO
00 OS 00 00 041 ••
SO 00 • •• •• • Oa
SO
00 00 041 OS 00 OD
0 Q .0 ite1".•0ree0 to
10
• •
g
••
00
0000 0 tee
0 a•
00 0 0 00 in
•
.A
•
.4
ro
•
00 •• 660
as
00
00 00 40 00 00
00
Om
000
000
\ 1.1 1.-‘ A 00
r-I AAAA
R
0
0 0 LC'.Q0
CU A
r4
r4 r4 r4 r4
0
$,
am
00
OS 00 00 00 00 41.0
00
•• •• 00 0.
00
06
Al 0.1 e-4 ri au au
00 WO 00 00 SO 00
••
00
00
00
•
to
s.1
d mI
06 0 0
O• OS 00
00
410
ahcl
00 40
O•
A r.4
a3
t, .L.4,1
" .si0
io' 7 IP/
i
ttf
00
Likg g5).
•
0. 0
F. 40
01
0 a)
• AO
0
GO 00 00 00 00
00
g9,88 g
0
Q0000
CV,
LCNaD
000000
.-1
o
_ .
06 OA
0
14.9 ..G
teN
▪ Nri
00 00 00 •0 00 00
WI
••
:'1
-.
rg0
t.
a
1.4 ei
g
CV 42
,-. sp ee
• •
se 0
11.
al C.CO 0
13 lk
• LCI
A 4. la• 01
V) ea
4•D
.1-*
66 •• a ma ••
la
ir a..
0
ra.
ra
.. ...
00
r4
8•-IRAEis'
,9, g
ri
A CU
O.Fa9-3
14". CV CV ri 1,,
N
.. .. .. .. .. ..
gg aR89.
r4
00
.,. .. .. .. .. ..
a ft' lec‘l3 Cu
g
C MCU CV
Cu
XI
00 00 06 00 00 OS
0•
06
•
Q0000 0 0
..i
O H..0' T. r-e..0
PC\ r,..
Pr1...* 1.11%) Pr\
0 0 0 Cr\
0 0 0
CO •0
1:0 01 an w%100 f'•-•D
VD
4'1 11'
LCY
k0
CO Is.
M
f-10
2
P•)
00 00 00 SO 00 00
GO 00 00 00 00 *lb
e. ...
10
01
e• •• so •• •• ••
.4.
R000000
.4 00 W nD 00
0041W 00011:0 00
4
4* ••
••
so
0 0
00 Q
0 0 0 0 0 in 0
In LC
map
0
0 0 0.-1 %.13
0• 00 60 40 1.0 On
4•1 lu
0 4>
0
00011\00 , -I
U a 150 %CO a..0 r- r- no r-
A 1 :3 . "i
..-. g ....1. 4,
0)
43/4 a:01
11-4
0
ra
ri
sa
0
00
al
00 00 00 •• 40 00
0 0 0. 0 0 0
0 0 0 0 Q 0.1
0
r--
00 130 00 %. D
•W\ CO
as
SO 00 00 00 •• ••
oe
e4
00 00 00
S
•
•
0
Ow
al
.
i -,i i 1i :8
Pee
a
a ?,
1 cp
OA
00 00 00 00 40 011
q
..V ...4
0
Lr,
gagag
1
al
40
-r-c
0
LO
'5°
01 rL 0
O
•
0 0 0 0 0 0 C.11 0
0
,1 f.'s IN .4
es
.. -
O
Oo
0
0
0 In WO e.".
r.'n
I• A o-I a%.1%.C1
161
‘C 07 In0
C. $4
.
a V P. 0/
CU
.Q
k ..-i
4 11
4
•
Pe%
F-4
0 el
•.-•
00
WI
.4
00 WI0 0
0 0
Is-.
In Is.Is...4.
0
00 Ill .4'
N4000000
r4 r4 r4 r4 r4 r4
r;
00 60 06 •• 00 00
OS
're
cc.
0 4,1
1•1
so ••• ••
Q
O .§ 0 0 0 0
ON CO MP.- WN 1
In NNW
LC1.4.
0
00000 a
r4 r4 r4 r4 r4 r4 e4
•• 00 •• 00 00 00
••
a)
0, m 1 40
0
0
01
0
d
(14 Pe
44 if
•
tC\
• 0
•
• • •
N-
k0
0 49
1/1 0 0 0 W%
(1.1
r4
r4
Om 40 00 00 00 06
00 00 SO 00 00 00
0
00000
I:0
1410 r4
r•-•,,
re, C11 CU cr.
0
0
0
0
CU N1 PON Pr1 N1 Cu
Q. 0
Is-
00
00 00 60 00 00 00
00
8
8,i9S
aR 2 8
re‘.4' CV CV .4'
M
M 14114 1 In 141 Pe1 IM
0
0
ri
0
lee
0 g ag a4
Z:3
°
r- Cu
\ 1,1 N1 en N1 N1
U1 LINO
lC1ri
14n. rI R 14N1
1./J Pri
Na
••
00
O 0•
O N0
a El A
rn
•
00 00 00 00 OS
A CU tr1.4 1C1%.0
.4 CV 0•1..1" InAD
4.1.7 ItlaD
4
0
0
1,1 N
0 rt
r•7
•
8
a
0 00 ee 00 00 00
..
•
•
00 00 00
40
0 0 0 0 0 0 0 u
a
Ga
•
0
0 00 00 00 00 00
]
•
44
00
....n
r
13
-1
N •
0w v
•
al
..-I
a.
-.
i• I
•
•
LI
•
ca.,
to
0
00
•. 00 00 00
..
la.
"d
00 00 00 00 60 00
og0000
o
.0' 111..l• in 1/40 0
VD
•-•
0 0 0 0 0 0
00 00 AO 40 00 00
0 0
.4* .0*
00
N•
1/41;) 1/40 N•
rl
•rri
V
F
•
0
1/40
r4
4•
0
I P.
•
.1-4
•
54
•
P•
g
m
45
.5
U,
,q
8S2S8R R
I
00 00 60 00 00 00
00
5
a
."4
000000
0
a* 00 00 00 00 00
00
00
LC)
r-11
•• •• ••
•••
00
0pt,o,
00Q
o to0r10*..0 r4
1,
••
40
04
tf\r4 00
.4'
•• coo ••
00 00 00 00 00 00
00
Oa
1.4
•• ••
o
I.\
'6
cr,
go F0000
r4 MO 00
•-I
•ILI
0
•
rr
.
r.I
0
•
%.1:0
oo0000
0
r-1 0 0i is'
0 wl11.-1(11r1/40
4.4• 1.-•NO• ONO0 UN•
r4 P4-1 r4 CU
.0? 54.; a
I.
0
0 u10 0
°
I1 11.3 .0' P--1/40 N
.4'
. ..
*
T-
0 0 0 0 0
00 ee 00 00 00 00
pm
F.
-4A
0 00
••
•
r4
00000
t•-n 0
t1.1
000000
.8 18. g0..8 !ER pr
Ifl
..
•
00
•o
r4 N orb r•4 r4
•• ••
40
•• •• •• •• ... ..
••
A..1
Oa 00 00 00 00 00
Lt,
0
0 0 00 R., 0
r`-,71 nD Is- CM I,•
Q. 0 0
0
rs1 °1°
Pr%
1.1
r4 rt
a
•r4
FAR.S13R2,
ICV
• ••
#
0
0
4.
0
0
• •
•0
•• •• ••
•• ••
• •
•• •• ••
-1
W.%
p.
0
0000000
000000
INtcr-jR,9,R2
fa,
1411:0 W%
0
00 06 Oa 00 00 60
0 0 0 0 0
00 00 00 00 00 00
I
P-
• • 0
A
4
•
0
111
c‘i
V
0
8,R v)
°
000000
r°•-, RRRRR R
ur,
CU
00
00 00 NI 00 OD 00
g
o
o o o o o o 0 1c
0 0
0
00 00 00 e• 00 00
CPI
se
00 00 40 00 00 00
0
q-I
0
0
Cia
lti
0
14
0 0 0 0 0 0
00
.R
51, R t'inq.,
•
4.
03
00 Oa WO
ICA 1.91 C
IA 8
r4
r4
00
a
so
0
g
Se
m
P--
..-1
d; co
co
R R FA R g
al
00 00 06 00 00 00
00
00000Q
Pr1 Pel CU MN IV
00 00 00 00 00 00
-
o go R8 o
000000 0
0000000
F.
4
44 4'4
g
•
I.
00 00 00 00 ea 410
e• e• ee
00 00 00
00
0.
0.
r--
0
00000
rs'‘an.0-
ea %.0
c0
0
0
0 r0--.4
to Lo
r..o
.. .. .. .. .. ..
..
00 00 00
00 00
00
00 Oe 00 00 00 00
00
oooooo
R
Ir.
.4
ro_Rgooks•
g
0•11.- Kvg to
0
r - 00 va 1/40 r-4 Ill
1/40 .4. I....4. .-4l0
.4 .4-•.4 .4. .4 .4
06
g
Ro Ro R
% .D g m to
141
cv••••••
A'
.a• .0- .0" k
03
••••n
.4' .0' r.1.0'
••
00 00 00 00 00 00
44i
•
O 0
0 i
a M
i
C•R, 0
144 Ck, r'1.0* Imo
s'l 0‘.1 141.-1- inu,
.4
.
.41,
r4 CU 141.4. LCV..0
I>
4
0000000
16:
•
•• •• IND 00 00 NB
8
Ro o
NI
•• 00 00 0410 •• • s•
!e
i
03 0
•
Ill
r4
V
11)
0
es so
0
$4
.0 4.
06 •
••
1
60 Orb •• 00
•• 00 Oa 00 06
R82 8
ReRRS8
00 OD 00 00 IND 00
00
Oa
I
b
0 0 0 0 0 0 0
.1
GO
0 0 0 0 0 0
0 IP
se ell se 46 o*
••
0 0 0 0 0 0 0
0
Cr
00
11-
/3
Rfa8
g aR S 4
LeN.-1*
le%.-7 A'
0
en
a.
1>
n.
.• •• • •
40A t ••
0 44
0
I 4.11
OD
60 •• IDS 00
00
co
00
••
000 0 0 0 0
g
.71 r1 s-1
0
•
0.
to
\
•• 00 ••
••
00
a)
••
•
O\
Le1 r--
0000 0
O
0 0 0 0 0 0 0
OD
RS229,2 a
0 0
•• • 00 00 DO 00
ND 00 00
•• 00 •• 60 IND 00
02 0
0
0
Orb 00 IDS 00 OD ••
GO
044
40 A1
'M
0 0 0 0 0 0 0
0 0 0 0 0 0 0
0
4
q
0
•• •• OD Oa 00 00
0
0 0
g.
81. 00
4.
••n
••
to
0
000000 0 1
0 0 0 0
00 On 00 •• 00 ••
0 0 0 0 a
r.1
i41%.0
.4
1,- r4 I-1
fAt R.?: '
Pa
•
00
0
000
n.0 1/40 U RA %1:1
r•••
r••••
r•-kA
60 00 •• 00 00 .0
0 0 0 0 0 0 0
•• 06 .6 •• 00
be
•• .
R
40
.1'
IL, /CNA-
a
....N.
8RaRP48
A' A- A06 00 Ow 00 •• 60
0
00
O
q
1"
000000 00
M MIA1141141M N 0
60
V
c
P.laRRF4R.
••
0 00000 04
.
rl
•C1
•
1.1
41100.•0 1110 ••
8
n
scoAsag s
aaaaaa a
00
•• •• 00 00
••
gg g
(% e. r cu.
SO •• 06 00 06 00
• • • •
OS
01 N cu
N
•• OD GO 90 O.
••
0 0 0 0
r-1
IND
00 00 1110 IN 60
la
11.11
OD
OD GO OD ••
8
100 03
b0
00
1.•••* ob..**
00
141WW101MM
anigi
*
0'1
•
1'4 N 111.0 1/1n0
rl
,4,4,4aaa A
00
60
ow MP coe 00 am a.*
r4 N r&t..* u,.0
00
1r1.4 0.
0.1
0,42
0 0 0 Q. 0 0
IMO %A 1n1 00 r4
r1.0. .0. MN In
gsge
00 .• 00 Orb 00 •6
00
.4
rr1.1 1.1"0
0.
•
a)
44
0,
+.1
000000
•
00ORRIR c-
0000iZR
•• •• .•
C
0
1/40
0
cc)
cp.
r4 40
1.4 g
CS 0
I~
U3 V)
o
•• ••
cr.!,
••
••
.•
Cr3,
,c•IRRRRRI
•• 00 SS •• OS 00
00
•• •• 00 •• LOO 00
0000o0
0
o o t .g 0
14;
•• •• •• OS 00 00
••
••
••
••
••
RI 4;3%04
al
SO 00 00 .0 00 S•
••
2. e
co
Or
.0 .4
cfaji
•
0ceN
C)
C)
Q
0 0 0 0 s0
CV rnN
-I
r-I
04
00 00 00 MO
•• 00 00 • • •• ••
00
40
CC ID
ID 24
.0 4.
s
pk
ao
8
U) 0
.... .... ....
.•
C.1
C)
40
.1-.
O
a a 0 0 0 0 0 0 a
o C.,
I-1
a
a
a
P.a
a
•
a
CD
X1/4
ren
01
-
O.
11.
• • •• •• •• 00
•
a
a)
4...
s-4
a
1...
0)
04
11)
▪
4.4
r-.
• •
a
0
0
a
Ii
0
,r_i
8R28?8
F.r-I I-4
C
O
O.. 00
0
K
00 00 •• 00
o•
8 °g
.0
2
-ei
07
..4
0
0
osf
q
F.:
e-I r11.1
g
la
I-I
a
a
so •• .4. •• .• ••
al
a
....
a
.. •• .• •• •• .1..
a
Cr.?,
I' E 5c-.4 ,9,s. Lci,
r-4 .-I r-I r4 •-4 .-4.-1
0
....i
§. 8 ,9„?, 8 2
0
.• ..
00 DO 00 OD
•01`
o 000000
..,i .
0
...• .. .. ..
.11
I.-,
-.4.0 0 0 0 0 0 0 4 o o 0 s 2 ?.,
b01 RI eel '41 MM
Lk 0
,r•
•-•
f1/4.1... CU CA; CU al.ca
co
ilt
a
••
ca
a,
-.4
1-• '
ri
El
A
CU
U Se,
•• •• .. •• .• ••
••
.pi
•• •• •• •• •• ••
C)
ct.
f g, 9 0.1 0 ro...,
a
. 0 0 0
b0 CU ON 6
•
• • •
•
r,I
r•I r-I r-I
rl
so •• •• •• •• ••
••
MM
M
00 WO 00 410 00 ••
RI
M
00
0
E,'
0 'a 000000 Cu
0
el
CO
• •
,:.
0
0
Lnr
0 M
tr,i
44.
IN 00 00 Os ..••
sig
'A FA 2 R R, PI..- 1.--.A•• r- ).,D I-- '.0
a
a
••
al
..
MN
0
5
..1 g
0
o o o 0 o o 0 1
0 0 0 0 0 0 M
L:r
K2 "
ri 2.0 Ph 24114N-1-
r-1
.. .. .. .. .. ..
O
••
rm..,
•• .....• ....
es
ok 0 0 0 0 0 0 ck, a 0
0 01-410 0 0 Ill
r-I .4
r-1k
Ci
1' 1,1
q
MI 0 0 0 0 0 0 s...
.... .. •. •• oo
F24
oo *a oo los oo oo
••
g
0 0 0 O M 0
' s "S.,
LiTh CO 0 r•I 'es O
• •
0
mc
a)
J-n
•• •• •• •• •• ••
ea
Ftgogog cr.1-,1
ds• ea. so so so oo
so
0 o or•-•o
oo
WNW %.0
r-I Ca 1 la A- %.0 1/4.0
•••••••..
..
r-4 r• I ri r-I 4-1
r4
00
OS •• 00 00 00 ••
••
0 0 0 0 0 0 0
R° °
A .-I
.-I
00 *0 GO 00 00 00
CU
•
"-CCi
••
40 Al
A 4.
a
a s.
CI 4.
CO
a
1;31
tr'l
.0
OS
00
00 00 OS
DJ
••
0 0 0 0 0 0 0
rI
LCN
a,
11").0- DJ 0 1.-- 60
C%:. 5.4 M r•-`: Or a a
0. •• •• •• •• ••
r-1 Cu MN.-1- if1/41/40
•• 00 •• 00 00 00
SR
0 0
are
'A 8
r•-• ICS IC-.
C1/4r Or Or 07 C1/47 CU.
00 00 00 •• 00 e•
000000
tO
0 r-I
F.^%
\DOW r42./30
.0.00
fel re% Cu pc... N 1,).
00
0
tol
2.4-,24 cos
•• 00 00 00 00 00
fe%
I 8 &PRI`
g
N
00 00 OD 00 III. 00
130 1-1
00 00 de 00 00 GO
°.?8°°2 e
00
AI 0
b0
,cl!
N10. CU 0 CU DO 0
00
r4 re%
RJR R
am
0110 GO 00 00 MD 00
giggsit2
00 OM 00 00 00 00
00
R8°2° °
FARRIE` g fa'
2
.r0
00
C
Cr.
0
67
4
GI
GI";
14
CC.
•
.?1D0
CU 0%
te‘ta 141.4
0
r
-• .*
11.4
-4 -4 r e r4 rs
•
ike
••
00 VD 00 00
M
ri 00
N1141 l•-•.0
N.V•
NO
00
0
r4
4
.4,
U
0
•-n
••
00 00
••
00
00
00 00
00
U
•"
.
••
07
I. 0
-1..
100 CI
0
I.
A0 r4
.4
P.
tr),
sr-
a.-%
•-•
CI
111 0 r4111i1 ...I
0
,
0
0
1.0 0,
•
R
titA ∈
F.
0 0....
M.
0,
rd .4
...,..,,,zo. .2
O 14•0
o
-V +3 A. $4
En co
HO
MI.
•• 4
1.
• ••
•
00r40
•
•
E e
....
00 MD
a) g
88RPRR
&-,
r.4 ri
R
44
44
00 ea
Mb 00
••
LC,
elO3 r.-0
1•
•
•• 00 00 00 00 00 00
00
..* cr, c.., 3 0 al
0 0m Z.' CV ,--1 r-- 0 int 0
..0N tO %. LI rev*
M
Mg V r4
rlr-I (11 .-I
CU
.,-.
r.I 1.101 .,a
'es 00
CU 1•101
M
0
• g
11 .0
g
r.:
••1
a
00000
0 CU
4.4 CO
1•1
N.D r.4 1.1
a
DO
in it% 0 on 0 UN 0 1: po 8
r.1 ..1 ..I r4
al [Ar
0 0
W
P.
0
00 00 00
0
•., I40
4I) 2 •
(1)
M
01•
"
41
4 g01
a
E
U
..-1
J0
CI ...
- 40
00 •• 00
••
..
14
a)
0
F. 4.5
P. O
.4
4.4
•
.. » » « .• w
R
WI
44
co
a)
41
p iRtm
00 00 00 00 00 00
ND
M la
...
g;
.-s
1.
5 .44•-I
0 1.1
0 06-4
0 NZ
0 CU
10M
st.
0
. 1.,
rm
4..
•, 0M
II
.• .. ... .. .•
00
•••
r--
t - •
.4 0 00
yinps.,stve 0 ..a w0cu N1N1N.. 0 4:03. 4P1'
I.
0 4: co .g0p,
1:
1, %0 .-O CU tO ,I C‘I 2
CC
r4 0101..4 01
O T.
C %.1) 00 V) 11
1 IMO 1 0 111%0
e `
t Mge M
V) % D I.-VI
.0
+
3As
FL
Id.
tn 0
,,,
O
O .• /.
•• •• .. P., 3 60 ••
CD
00 00 00 00 00 NI
00
••
coC. a 4) o
,.
w
0
NI
la
14
m§ 01
0 0 0 00 0 CU
M .-I 0 C
riCR2 u"' iliN R g 8 9, IF3` 8 gg c" 'I' 4 0
141
14 CP
4 .-,
.+1
0 .-1 r4 Is- ,-,
0
..-I
l
0 0
P.,1 N•
c15
•
P.
Is:
•• .• 44 ...
o
.4I-1'3
r V>
•r4 te
M
.1
•••1
PId
01
,0-
oN
;I
0 r4 0
v ed
r.:
•
Le.
-
u
at
f..
•
40
F. 0
0 F.
••
00
••
0411 00
M
N
•-i
at
E -1
40 00 OD 00 00 de
•••
A
•
P.
r.-
to
...?
61 r4 •+I 6,-1 .-I 4-1
E - 3,-Awru.
N.0 /11 %.0 re.
• 4 Hrivirlr4r4
.......•
rl
15
), z
Er\
a)
.. .• .., ... .• ..
.4
..4
0
in
0.1 r4 1/11/10
.?4
lo▪
.4 t o m
..
.
,..4
P. ti
.• .• •• •• .•
ID
..t
1.1
laE0 m
Al ...
•.
t.0
A CI
.4
KNCI
r4 0 1•1
0) .-4
a
.0...0
41:0 I. •
di'.
N.1.4 .+I
?,
00 00 00 00 OD
00
.42Sid0g1
0
N+.71.ID111 g1"
00 N.0
lb
1.1 1.1 N1 N11.1 N'N M
1.r%
00 00 00 el• 00
••
▪
_I CV N%.* LC1143
... .. .. 44 .. ...
§
F4 § ?i 8
00 MO
••
• • • • ••
on.
•• • •
••
..-P
..
de 00 00 OD 00
orr.,,o 2
...
go 2 g
00 00 00 00 00 00
ON re10
ri1 0
VCge3N*
g
10
•n
MM MM MM M
.-I N N"N.* ICNNO
4•
I.
4)
A0
•• •• •••
N
I.-ND
W.0 8
CU CU
0,1
11100 b0 ...CZ N.,0
00
R3.4G1 N.
00 0 N..
11"1
00 • N.-
In
•
0
r4 rl r4 r4 r4 r-4
•••
A
r4 CU MA' IL1N.0
O
co
co
Figure 1.-.Results of tests of 1/2-inch lap joints
1 inch wide of 0.064-inch clad 243-T3 aluminum
alloy bonded with adhesive 25.
ZM81569F
Rept. No. 1808
Figure 2.--Results of tests of 1/2-inch lap joints
1 inch wide of 0.064-inch clad 24S-T3 aluminum
alloy bonded with a combination of adhesives 25
and 30A.
ZM81570F
Rept. No. 1808
Figure 3. '
-Results of teats of 1/2.-inch lap joints
1 inch wide of 0.064-inch clad 24S-T3 aluminum
sally bonded with adhesive 42. •
2118 157 1F
Rept. No. 1808
Figure 4.--Results of tests of 1/2-inch lap joints
1 inch wide of 0.064-inch clad 24S-T3 aluminum
alloy bonded with adhesive 35.
ZM81572F
Rept. No. 1808
Figure 5.-4-Results of tests of 1/2-inch lap joints
1 inch wide of 0.064-inch clad 248-T3 aluminum
alloy bonded with adhesive 34.
ZM81573F
Rept. No. 1808
Figure 6.--Results of tests of 1/2-inch lap joints
1 inch wide of 0.064-inch clad 24S-T3 aluminum
alloy bonded with adhesive 44.
Z1481574F
Rept. No. 1808
Figure 7.--Results of tests of 1/2-inch lap joints.
1 inch wide of 0.06L inch clad 24S-T3 aluminum alloy
bonded with adhesive M394, cured 20 minutes at 320° F.
at 250 pounds per square inch.
Z148157511
Figure 8.--Results of tests of 1/2-inch lap joints 1 inch
wide of 0.064-inch clad 24S-T3 aluminum alloy bonded
with adhesive M471, cured 30 minutes at 240° F. at 250
pounds per square inch.
ZM81576F
Figure 9.--Results of test of 1/2-inch lap joints.1 inch
wide of 0.064-inch clad 248-t3 aluminum alloy bonded
with adhesive M487 cured 24 hours at 75° F. at 250
pounds per square inch.
ZM81577F
Figure 10.--Summary of figures 1 through 9. The strengths
are for the intermediate curing condition for the adhesives noted at the left ends of the curves.
ZM82136F