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Polyurethane

Crystal Clear™ 221

Crystal Clear™ 221 is listed by Smooth-On as a polyurethane casting resin. The source reports mixed viscosity of 675 cps, mix ratio by weight of 100A:75B, pot life of 75 minutes. This record connects 19 reported fields with 3 manufacturer document links. Review the original technical data sheet for the applicable test conditions and processing instructions.

Technical data sheet Safety data sheet
675 cpsManufacturer-reported
100A:75BManufacturer-reported
75 minutesManufacturer-reported
24 hoursManufacturer-reported
85Manufacturer-reported
1.07 g/ccManufacturer-reported

Technical & safety documents

3 links
Files open on the manufacturer's document host. Region and language follow the source listing; confirm the revision inside the file.
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TDS
Technical BulletinEnglish · Not specified
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TDS
UV ASTM CertificationEnglish · Not specified
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SDS
Crystal Clear 221 SDS | EnglishEnglish · United States & Canada
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Reported specifications

19 fields
Material and processing data
PropertyReported valueEvidence
Mixed Viscosity675 cpsManufacturer table
ColorClearManufacturer table
Mix Ratio By Weight100A:75BManufacturer table
Pot Life75 minutesManufacturer table
Cure Time24 hoursManufacturer table
Shore D Hardness85Manufacturer table
Specific Gravity1.07 g/ccManufacturer table
Specific Volume25.9 cu. in./lb.Manufacturer table
Compressive Strength10,100 psiManufacturer table
Elongation @ Break12 %Manufacturer table
Flexural Modulus305,000 psiManufacturer table
Flexural Strength11,400 psiManufacturer table
Heat Deflection Temp176 °FManufacturer table
Index of Refraction at 20°C1.50084Manufacturer table
Index of Refraction at 25°C1.50035Manufacturer table
Shrinkage0.0173 in./in.Manufacturer table
Tensile Modulus286,000 psiManufacturer table
Ultimate Tensile8,190 psiManufacturer table
Compressive Modulus87,000 psiManufacturer table
Reported values are not independent test results. Original units and table wording are preserved. Extracted TDS rows can depend on the grade, component and source table headings; use the linked page to verify that context. Test methods, sample preparation and cure schedules may differ; consult the original TDS before making a performance comparison.

Selection & processing checks

Distinguish rigid casting plastics, elastomeric rubbers and foams. Their density, hardness scales and processing requirements are not interchangeable.

  • Is this a solid material or an expanding foam?
  • Which hardness scale and cure conditions are reported?
  • What moisture-control and preparation steps does the manufacturer require?
  • Confirm the complete product designation, including any hardener, color or formulation suffix.
  • Read the current SDS for handling, protective equipment, storage and disposal information.

The reported weight ratio for this record is 100A:75B. A weight ratio must not be used as a volume ratio without the appropriate density information.

Missing properties are not estimated. Similar values or shared application labels do not establish a drop-in replacement.

Other materials in this family

View collection
Material / manufacturerFamilyKey specificationDocumentsAdd to comparison
Clear Flex™ 95Smooth-OnPolyurethane250 cpsMixed Viscosity2 linked
Crystal Clear™ 200Smooth-OnPolyurethane600 cpsMixed Viscosity3 linked
Crystal Clear™ 202Smooth-OnPolyurethane600 cpsMixed Viscosity3 linked
Crystal Clear™ 204Smooth-OnPolyurethane600 cpsMixed Viscosity3 linked
Related records are browsing suggestions, not validated substitutes.