ETC 113082

Technical Data Sheet
Product 638
Worldwide Version, October 1995
PRODUCT DESCRIPTION
LOCTITE® Product 638 is a single component anaerobic
retaining adhesive which develops high strength rapidly when
confined in the absence of air between close fitting metal
surfaces.
Cure speed vs. temperature
The rate of cure will depend on the ambient temperature. The
graph below shows shear strength developed with time on steel
pins and collars at different temperatures and tested according
to ISO 10123.
PROPERTIES OF UNCURED MATERIAL
Range
2,500
1,800 to 3,300
2,250
>93
1,500 to 3,000
TYPICAL CURING PERFORMANCE
Cure speed vs. substrate
The rate of cure will depend on substrate used. The graph
below shows shear strength developed with time on steel pins
and collars compared to different materials and tested
according to ISO 10123.
% of Full Strength on steel
100
75
Zinc Dichromate
50
Steel
40°C
75
22°C
5 °C
50
25
0
5min 10min
30min 1hr
3hr
6hr
24hr
Cure speed vs. activator
Where cure speed is unacceptably long, or large gaps are
present, applying activator to the surface will improve cure
speed. The graph below shows shear strength developed with
time using ACTIVATOR N and T on zinc dichromated steel
pins and collars and tested according to ISO 10123.
100
75
No Activator
50
Act T
Act N
25
0
5min 10min
Aluminium
30min 1hr
3hr
6hr
24hr
72hr
Cure Time, Hours
25
TYPICAL PROPERTIES OF CURED MATERIAL
0
5min10min
30min 1hr
3hr
6hr
24hr
72hr
Cure Time, Hours
Physical Properties
Coefficient of thermal expansion, ASTM D696, K-1
Coefficient of thermal conductivity, ASTM C177, W.m-1K-
80 x 10-6
0.1
Specific Heat , kJ.kg-1K-1
0.3
1
Cure speed vs. bond gap
The rate of cure will depend on the bondline gap. The following
graph shows shear strength developed with time on steel pins
and collars at different controlled gaps and tested according to
ISO 10123.
% of Full Strength on steel
72hr
Cure Time, Hours
% of Full Strength on steel
Chemical Type
Appearance
Specific Gravity @ 25°C
Viscosity @ 25°C, mPa.s (cP)
Brookfield RVT
Spindle 3 @ 20 rpm
DIN 54453, MV
D = 129 s-1 after t=180secs
Flash Point (TCC), °C
Typical
Value
Urethane methacrylate
Green, fluorescent liquid
1.09
% of Full Strength on steel
100
TYPICAL APPLICATIONS
Used to bond cylindrical fitting parts, particularly where bond
gaps can approach 0.25mm (0.01") and where maximum
strength at room temperature is required. Applications include
locking bushings and sleeves into housings and on shafts.
PERFORMANCE OF CURED MATERIAL
(After 24 hr at 22°C on steel)
100
Typical
Shear Strength, ISO 10123, N/mm²
(psi)
Shear Strength, DIN 54452, N/mm²
(psi)
75
0.15mm
50
Value
31
(4500)
27.5
(4000)
Range
22 to 40
(3200 to 5900)
20 to 35
(2900 to 5000)
0.05mm
25
0.25mm
0
5min10min
30min 1hr
3hr
6hr
24hr
72hr
Cure Time, Hours
NOT FOR PRODUCT SPECIFICATIONS
THE TECHNICAL DATA CONTAINED HEREIN ARE INTENDED AS REFERENCE ONLY.
PLEASE CONTACT LOCTITE CORPORATION QUALITY DEPARTMENT FOR ASSISTANCE AND RECOMMENDATIONS ON SPECIFICATIONS FOR THIS PRODUCT.
ROCKY HILL, CT FAX: +1 (860)-571-5473
DUBLIN, IRELAND FAX: +353-(1)-451 - 9959
TDS 638 October 1995
TYPICAL ENVIRONMENTAL RESISTANCE
Test Procedure :
Shear Strength, ISO 10123
Substrate:
Steel Pins and Collars
Cure procedure:
1 week at 22°C
Directions for use
For best performance surfaces should be clean and free of
grease. Ensure joint is completely filled with adhesive. For slip
fitted assemblies this is achieved by applying adhesive around
the pin and the leading edge of the collar and using a rotating
motion during assembly to ensure good coverage. For press
fitted assemblies adhesive should be applied thoroughly to
both bond surfaces and assembled at high press on rates. For
shrink fitted assemblies the adhesive should be coated onto
the pin, the collar should then be heated to create sufficient
clearance for free assembly. Parts should not be disturbed until
sufficient handling strength is achieved.. For more detailed
information on using retaining adhesives contact your local
Technical Service Centre.
Hot Strength
Tested at temperature.
% RT Strength
100
75
50
25
0
0
100
50
150
Temperature, °C
% Initial Strength, at RT
Heat Ageing
Aged at temperature indicated and tested at 22°C.
125
Data Ranges
The data contained herein may be reported as a typical value
and/or range (based on the mean value ±2 standard
deviations). Values are based on actual test data and are
verified on a periodic basis.
120°C
100
150°C
75
50
25
0
0
1,000
2,000
Hours
3,000
4,000
5,000
Chemical / Solvent Resistance
Aged under conditions indicated and tested at 22°C.
Solvent
Temp.
Motor Oil
Unleaded Petrol
Brake Fluid
Water/Glycol (50%/50%)
Ethanol
Acetone
125°C
22°C
22°C
87°C
22°C
22°C
% Initial Strength retained at
100 hr
500 hr
1000 hr
100
100
100
95
100
90
100
90
90
80
100
90
Storage
Product shall be ideally stored in a cool, dry location in
unopened containers at a temperature between 8°C to 28°C
(46°F to 82°F) unless otherwise labelled. Optimal storage is at
the lower half of this temperature range.
To prevent
contamination of unused product, do not return any material to
its original container. For further specific shelf life information,
contact your local Technical Service Centre.
100
85
80
80
75
90
GENERAL INFORMATION
This product is not recommended for use in pure oxygen
and/or oxygen rich systems and should not be selected as
a sealant for chlorine or other strong oxidising materials.
Note
The data contained herein are furnished for information only
and are believed to be reliable.
We cannot assume
responsibility for the results obtained by others over whose
methods we have no control. It is the user's responsibility to
determine suitability for the user's purpose of any production
methods mentioned herein and to adopt such precautions as
may be advisable for the protection of property and of persons
against any hazards that may be involved in the handling and
use thereof. In light of the foregoing, Loctite Corporation
specifically disclaims all warranties expressed or implied,
including warranties of merchantability or fitness for a particular
purpose, arising from sale or use of Loctite Corporationā€™s
products. Loctite Corporation specifically disclaims any liability
for consequential or incidental damages of any kind, including
lost profits. The discussion herein of various processes or
compositions is not to be interpreted as representation that
they are free from domination of patents owned by others or as
a licence under any Loctite Corporation patents that may cover
such processes or compositions. We recommend that each
prospective user test his proposed application before repetitive
use, using this data as a guide. This product may be covered
by one or more United States or foreign patents or patent
applications.
For safe handling information on this product, consult the
Material Safety Data Sheet, (MSDS).
Where aqueous washing systems are used to clean the
surfaces before bonding, it is important to check for
compatibility of the washing solution with the adhesive. In
some cases these aqueous washes can affect the cure and
performance of the adhesive.
This product is not normally recommended for use on plastics
(particularly thermoplastic materials where stress cracking of
the plastic could result). Users are recommended to confirm
compatibility of the product with such substrates.
Loctite is a Registered Trademark of Loctite Corporation, Hartford, CT 06106