TC-821 A/B Page 1 of 2 Date: 09/20/2021
For more information call BJB Enterprises, Inc. (714) 734-8450 Fax (714) 734-8929
www.bjbenterprises.com
RIGID POLYURETHANES
By BJB Enterprises. Inc.
An ISO-9001 Certified company
TC-821 A/B
84 SHORE D POLYURETHANE CASTING SYSTEM
TC-821 A/B produces a high impact rigid 84 Shore D material that is commonly used to make computer housings, models of all
kinds, artwork, and can also be used for electronic component encapsulation.
Convenient 1:1 by volume ratio High impact rigid material
High impact rigid material Fast demolds
Excellent for vacuum, pressure, hand, and rotational
casting
Exhibits high heat distortion temperature
PHYSICAL PROPERTIES TEST METHOD RESULTS
Hardness, Shore D ASTM D2240-04e1 84 2
Density (g/cc) ASTM D792-00 1.18
Cubic Inches per Pound N/A 24.7
Color/Appearance Visual Translucent/Colorless
Tensile Strength (psi) ASTM D638-03 7,600
Tensile Modulus (psi) ASTM D638-03 2.4 x 10
5
Elongation (%) ASTM D638-03 11.5
Flexural Strength (psi) ASTM D790-03 11,500
Flexural Modulus (psi) ASTM D790-03 3 x 10
5
Shrinkage (in/in) linear 12 x x 0.005
Izod Impact, notched (ft-lb/in) ASTM D256-05 0.75
Heat Deflection Temperature @ 66psi ASTM D648-04 195 F (90.6 C)
Heat Deflection Temperature @ 264psi ASTM D648-04 170 F (76.7 C)
Dielectric Constant, 1MHz ASTM D150-87 3.06
Dissipation Factor, 1 MHz ASTM D150-87 0.019
Note: Reported physical properties based on elevated temperature cured test specimens.
HANDLING PROPERTIES Part A Part B
Mix Ratio (by weight ) 100 90
Mix Ratio (by volume) 100 100
Specific Gravity @ 77 F (25 C) 1.19 1.06
Color Yellow Colorless
Viscosity (cps) @ 77 F (25 C) Brookfield 60 2,300
Mixed Viscosity (cps) @ 77 F (25 C) Brookfield 1,200
Work Time, 100g mass @ 77 F (25 C) 2 minutes
Demold Time @ 77 F (25 C) 30 60 minutes
Properties above are typical and not for specifications.
TC-821 A/B Page 2 of 2 Date: 09/20/2021
For more information call BJB Enterprises, Inc. (714) 734-8450 Fax (714) 734-8929
NON-WARRANTY “Except for a warranty that materials substantially comply with the data presented in Manufacturer’s latest bulletin describing the product (the basis for this substantial compliance
is to be determined by the standard quality control tests generally performed by Manufacturer), all materials are sold “AS IS” and without any warranty express or implied as to merchantability, fitness
for a particular purpose, patent, trademark or copyright infringement, or as to any other matter. In no event shall Manufacturer’s liability for damages exceed Manufacturer’s sale price of the particular
quantity with respect to which damages are claimed.”
CURE SCHEDULE/HEAT CURING :
Most of the physical properties can be achieved in 5-7 days at 77 F (25 C). You may use your own post-cure schedule but the
physical properties may vary from BJB s cure schedule of 1-3 hours at 77 F (25 C) followed by 16 hours at 180 F (82 C). Do
not exceed curing temperatures of 200 F (93 C). Support of the part may be required to prevent part deformation during the heat
curing process.
NOTE:
Re-blend the B component thoroughly prior to use. It is advisable to evacuate entrapped air prior to casting this system. The
use of a de-airing agent, (BJB s AF-4), can speed up the process. If further information is required, please contact BJB s
technical staff for assistance.
ACCESSORIES:
BJB offers silicone RTV mold making materials along with a wide range of accessory items. These include de-airing agents,
pigments, mold releases, and Jiffy
Mixers. Visit BJB s website at www.bjbenterprises.com or consult a BJB representative for
more information.
STORAGE:
Store at ambient temperatures, 65-80 F (18-27 C). Unopened containers will have a shelf life of 6 months from date of shipment
when properly stored at recommended temperatures.
PACKAGING Part A Part B
Cubic Inches
per Kit
Quart Kits 2 lbs. 1.8 lbs. 94
Gallon Kits 8 lbs. 7.2 lbs. 375
5-Gallon Kits 40 lbs. 36 lbs. 1,877
55-Gallon Drum Kits 400 lbs. 360 lbs. 18,772
SAFETY PRECAUTIONS :
Use in a well-ventilated area. Avoid contact with skin using protective gloves and protective clothing. Repeated or prolonged
contact on the skin may cause an allergic reaction. Eye protection is extremely important. Always use approved safety glasses or
goggles when handling this product.
IF CONTACT OCCURS :
Skin: Immediately wash with soap and water. Remove contaminated clothing and launder before reuse. It is not
recommended to remove resin from skin with solvents. Solvents only increase contact and dry skin. Seek qualified medical
attention if allergic reactions occur.
Eyes: Immediately flush with water for at least 15 minutes. Call a physician.
Ingestion: If swallowed, call a physician immediately. Remove stomach contents by gastric suction or induce vomiting only as
directed by medical personnel. Never give anything by mouth to an unconscious person.
Refer to the Material Safety Data Sheet before using this product.
WARNING: This product can expose you to chemicals including 1,2-Benzenedicarboxylic acid, di-C9-11-branched alkyl
esters, C10-rich and Naphthalene, which are known to the State of California to cause cancer and birth defects or other
reproductive harm. For more information, go to www.P65Warnings.ca.gov.
Handling Guide