EPO-TEK 353ND

spore: profile
id: epo-tek-353nd
spore_version: 0.2
family: epoxy
name: EPO-TEK 353ND
role: two-part high-temperature epoxy adhesive for semiconductor, hybrid and fiber optic assembly
category: seals-adhesives
type: adhesives
summary: EPO-TEK 353ND is a two-part, heat-cured epoxy adhesive sold by Epoxy Technology. Its datasheet gives a glass transition of at least 90 °C, a Shore D hardness of 85 and a suggested operating limit of below 350 °C for intermittent use. NASA's outgassing compilation lists the grade with total mass loss from 0.81 % to 2.03 % in a 125 °C vacuum test, depending on the row.
best_for: High-temperature bonding and potting in semiconductor, hybrid and fiber optic assembly, cured at 150 °C for 1 hour as the manufacturer recommends
weakest_at: 'Outgassing and hazard: total mass loss of 0.81 % to 2.03 % in NASA''s 125 °C test, and a Danger classification for Part B in the 2024 safety data sheet'
identity:
  formula: Two-part epoxy. Part A is an epoxy phenol novolac resin; Part B is an imidazole-based curing agent (components as named in the two safety data sheets)
  source: epotek-353nd-tds
  where: Title block (product name, rev XXXIII); component names from Part A SDS section 3.2 and Part B SDS section 3.2
  designations:
    - system: Trade name
      code: EPO-TEK® 353ND
      source: epotek-353nd-tds
      where: Title block
tags:
  environments: []
  stresses:
    - vacuum-and-outgassing
  applications:
    - electronics-and-chips
    - optics-and-cameras
properties:
  - benchmark: glass_transition_temperature
    label: Glass transition temperature, EPO-TEK 353ND
    value: 90
    bound: lower
    unit: °C
    scope: material
    conditions:
      cure: 150 °C / 1 hour (recommended cure)
      test: Dynamic Cure 20-200 °C/ISO 25 Min; Ramp -10-200 °C at 20 °C/Min, as printed
    method: Printed in the datasheet Physical Properties table; marked with an asterisk, which the datasheet says means a lot acceptance test
    status: ground
    note: Revision XXXI (March 2023) prints the same 'at least 90 °C' value.
    source: epotek-353nd-tds
    where: Physical Properties table, Glass Transition Temp row
  - benchmark: viscosity
    label: Viscosity, Part A and Part B mixed
    value: 3000
    value_high: 5000
    bound: range
    unit: cPs
    scope: material
    conditions:
      temperature: 23 °C
      rotation: 100 rpm, as printed in rev XXXIII
    method: Printed in the datasheet Physical Properties table; marked with an asterisk (lot acceptance test)
    status: ground
    note: Revision XXXI prints the same range at 50 rpm, so the test speed changed between revisions.
    source: epotek-353nd-tds
    where: Physical Properties table, Viscosity row
  - benchmark: shore_d_hardness
    label: Shore D hardness, cured
    value: 85
    unit: Shore D
    scope: material
    conditions:
      cure: 150 °C / 1 hour (Typical Properties cure condition)
    method: Printed in the datasheet Physical Properties table; test standard not printed
    status: ground
    source: epotek-353nd-tds
    where: Physical Properties table, Shore D Hardness row
  - benchmark: lap_shear_strength
    label: Lap shear strength, 23 °C
    value: 2000
    bound: lower
    unit: psi
    scope: material
    conditions:
      temperature: 23 °C
      cure: 150 °C / 1 hour (Typical Properties cure condition)
    method: Printed as '> 2,000 psi' in the datasheet; test standard not printed
    status: ground
    source: epotek-353nd-tds
    where: Physical Properties table, Lap Shear @ 23°C row
  - benchmark: die_shear_strength
    label: Die shear strength, 23 °C (printed as at least 15 kg, 5,334 psi)
    value: 5334
    bound: lower
    unit: psi
    scope: material
    conditions:
      temperature: 23 °C
      cure: 150 °C / 1 hour (Typical Properties cure condition)
    method: Printed as '≥ 15 Kg (5,334 psi)'; the psi figure is recorded and the kilogram-force figure is not; test standard not printed
    status: ground
    source: epotek-353nd-tds
    where: Physical Properties table, Die Shear @ 23°C row
  - benchmark: decomposition_temperature
    label: Degradation temperature
    value: 412
    unit: °C
    scope: material
    conditions:
      basis: as printed, 'Degradation Temp' row
    method: Printed in the datasheet Physical Properties table; test method not printed
    status: ground
    source: epotek-353nd-tds
    where: Physical Properties table, Degradation Temp row
  - benchmark: weight_loss
    label: Weight loss at 200 °C
    value: 0.22
    unit: '%'
    scope: material
    conditions:
      temperature: 200 °C
      atmosphere: not printed
    method: Printed in the datasheet Weight Loss row; test method not printed; typical value
    status: ground
    source: epotek-353nd-tds
    where: Physical Properties table, Weight Loss row (@ 200°C)
  - benchmark: weight_loss
    label: Weight loss at 250 °C
    value: 0.39
    unit: '%'
    scope: material
    conditions:
      temperature: 250 °C
      atmosphere: not printed
    method: Printed in the datasheet Weight Loss row; test method not printed; typical value
    status: ground
    source: epotek-353nd-tds
    where: Physical Properties table, Weight Loss row (@ 250°C)
  - benchmark: weight_loss
    label: Weight loss at 300 °C
    value: 0.87
    unit: '%'
    scope: material
    conditions:
      temperature: 300 °C
      atmosphere: not printed
    method: Printed in the datasheet Weight Loss row; test method not printed; typical value
    status: ground
    source: epotek-353nd-tds
    where: Physical Properties table, Weight Loss row (@ 300°C)
  - benchmark: max_service_temp
    label: Suggested operating temperature, intermittent
    value: 350
    bound: upper
    unit: °C
    scope: material
    conditions:
      mode: intermittent
      printed: < 350 °C (Intermittent)
    method: Suggested operating temperature printed by the manufacturer; not a qualified service limit
    status: ground
    source: epotek-353nd-tds
    where: Physical Properties table, Suggested Operating Temperature row
  - benchmark: storage_modulus
    label: Storage modulus
    value: 508298
    unit: psi
    scope: material
    conditions:
      temperature: not printed
      test: not printed
    method: Printed as '508,298 psi' in the datasheet; test method not printed
    status: ground
    source: epotek-353nd-tds
    where: Physical Properties table, Storage Modulus row
  - benchmark: dielectric_constant
    label: Dielectric constant at 1 kHz
    value: 3.17
    unit: '-'
    scope: material
    conditions:
      frequency: 1 kHz
      temperature: not printed
    method: Printed in the datasheet Electrical and Thermal Properties table; test standard not printed
    status: ground
    source: epotek-353nd-tds
    where: Electrical and Thermal Properties table, Dielectric Constant (1KHz) row
  - benchmark: dissipation_factor
    label: Dissipation factor at 1 kHz
    value: 0.005
    unit: '-'
    scope: material
    conditions:
      frequency: 1 kHz
      temperature: not printed
    method: Printed in the datasheet Electrical and Thermal Properties table; test standard not printed
    status: ground
    source: epotek-353nd-tds
    where: Electrical and Thermal Properties table, Dissipation Factor (1KHz) row
  - benchmark: refractive_index
    label: Refractive index at 589 nm
    value: 1.5694
    unit: '-'
    scope: material
    conditions:
      wavelength: 589 nm
      temperature: 23 °C
    method: Printed in the datasheet Optical Properties table at 23 °C
    status: ground
    note: Revision XXXI labels this value 'uncured'; rev XXXIII prints no cure state for it.
    source: epotek-353nd-tds
    where: Optical Properties table, Refractive Index row
  - benchmark: spectral_transmission
    label: Spectral transmission at 550 nm
    value: 50
    bound: lower
    unit: '%'
    scope: material
    conditions:
      wavelength: 550 nm
      temperature: 23 °C
    method: Printed as '≥ 50% @ 550 nm' in the datasheet Optical Properties table
    status: ground
    source: epotek-353nd-tds
    where: Optical Properties table, Spectral Transmission row
  - benchmark: spectral_transmission
    label: Spectral transmission at 1100 to 1600 nm
    value: 95
    bound: lower
    unit: '%'
    scope: material
    conditions:
      wavelength: 1100-1600 nm
      temperature: 23 °C
    method: Printed as '≥ 95% @ 1100-1600 nm' in the datasheet Optical Properties table
    status: ground
    source: epotek-353nd-tds
    where: Optical Properties table, Spectral Transmission row
  - benchmark: spectral_transmission
    label: Spectral transmission at 800 to 1000 nm
    value: 98
    bound: lower
    unit: '%'
    scope: material
    conditions:
      wavelength: 800-1000 nm
      temperature: 23 °C
    method: Printed as '≥ 98% @ 800-1000 nm' in the datasheet Optical Properties table
    status: ground
    source: epotek-353nd-tds
    where: Optical Properties table, Spectral Transmission row
  - benchmark: specific_gravity
    label: Specific gravity, Part A
    value: 1.2
    unit: '-'
    scope: material
    conditions:
      part: Part A
    method: 'Printed in the datasheet header block as ''Specific Gravity: Part A: 1.20''; test method not printed'
    status: ground
    source: epotek-353nd-tds
    where: Header block, Specific Gravity row
  - benchmark: specific_gravity
    label: Specific gravity, Part B
    value: 1.02
    unit: '-'
    scope: material
    conditions:
      part: Part B
    method: 'Printed in the datasheet header block as ''Part B: 1.02''; test method not printed'
    status: ground
    source: epotek-353nd-tds
    where: Header block, Specific Gravity row
  - benchmark: pot_life
    label: Pot life after mixing
    value: 3
    bound: upper
    unit: h
    scope: material
    conditions:
      mix_ratio: '10 : 1 by weight, as printed'
      temperature: not printed
    method: 'Printed as ''Pot Life: ≤3 Hours'' in the datasheet header block'
    status: ground
    source: epotek-353nd-tds
    where: Header block, Pot Life row
  - benchmark: flash_point
    label: Flash point, Part B (2014 SDS)
    value: 93
    unit: °C
    scope: material
    conditions:
      part: Part B
      sds_revision: revision 1, 07/10/2014
    method: Printed as 'Flash point (°C) 93' in section 9 of the 2014 Part B SDS
    status: ground
    note: The 2024 Part A and Part B SDSs print 'No data available' for flash point, so this value is not confirmed by the current SDS.
    source: purdue-353nd-sds-2014
    where: Section 9, Physical and chemical properties (Part B)
  - benchmark: chloride_ion_content
    label: Chloride ion content
    value: 329
    unit: ppm
    scope: material
    conditions:
      test: not printed
    method: 'Printed as ''Cl⁻: 329 ppm'' in the datasheet Ion Content row; test method not printed'
    status: ground
    source: epotek-353nd-tds
    where: Physical Properties table, Ion Content row
  - benchmark: total_mass_loss
    label: Total mass loss, amber-cured row (NASA)
    value: 0.81
    unit: '%'
    scope: material
    conditions:
      data_reference: GSC20704
      cure_temperature: 120 °C (cure time not recorded, see gaps)
      test: 125 °C for 24 hours in vacuum, collector at 25 °C (NASA method)
    method: Listed in NASA RP-1124 Rev 3, Section 1 (Adhesives) under the vacuum method described in the report
    status: ground
    note: The NASA listing says it contains only materials with a TML of 1.0 percent or less; the three pre-mix rows print higher values and are recorded as printed.
    source: nasa-rp1124
    where: Section 1 (Adhesives) listing, PDF page 30, row EPO-TEK 353ND HIGH TEMP EPOXY AMBER; method text on PDF page 8
  - benchmark: cvcm
    label: Collected volatile condensable materials, amber-cured row (NASA)
    value: 0.01
    unit: '%'
    scope: material
    conditions:
      data_reference: GSC20704
      cure_temperature: 120 °C
      test: 125 °C for 24 hours in vacuum, collector at 25 °C (NASA method)
    method: Listed in NASA RP-1124 Rev 3, Section 1 (Adhesives), CVCM column
    status: ground
    source: nasa-rp1124
    where: Section 1 (Adhesives) listing, PDF page 30, row GSC20704
  - benchmark: water_vapor_regained
    label: Water vapor regained, amber-cured row (NASA)
    value: 0.35
    unit: '%'
    scope: material
    conditions:
      data_reference: GSC20704
      exposure: 25 °C, 50 percent relative humidity, 24 hours
    method: Listed in NASA RP-1124 Rev 3, Section 1 (Adhesives), WVR column; NASA defines WVR as water readsorbed in 24 hours at 25 °C and 50 percent relative humidity after the vacuum test
    status: ground
    source: nasa-rp1124
    where: Section 1 (Adhesives) listing, PDF page 30, row GSC20704; method text on PDF page 8
  - benchmark: total_mass_loss
    label: Total mass loss, pre-mix pack (NASA, GSC12064)
    value: 2.03
    unit: '%'
    scope: material
    conditions:
      data_reference: GSC12064
      form: pre-mix pack, as listed
      cure: 24 hours at 25 °C
      test: 125 °C for 24 hours in vacuum (NASA method)
    method: Listed in NASA RP-1124 Rev 3, Section 1 (Adhesives), TML column
    status: ground
    note: Above the listing's own 1.0 percent TML limit; recorded as printed.
    source: nasa-rp1124
    where: Section 1 (Adhesives) listing, PDF page 30, row GSC12064
  - benchmark: total_mass_loss
    label: Total mass loss, pre-mix pack (NASA, GSC12067)
    value: 1.83
    unit: '%'
    scope: material
    conditions:
      data_reference: GSC12067
      form: pre-mix pack, as listed
      cure: 24 hours at 25 °C
      test: 125 °C for 24 hours in vacuum (NASA method)
    method: Listed in NASA RP-1124 Rev 3, Section 1 (Adhesives), TML column
    status: ground
    note: Above the listing's own 1.0 percent TML limit; recorded as printed.
    source: nasa-rp1124
    where: Section 1 (Adhesives) listing, PDF page 30, row GSC12067
  - benchmark: total_mass_loss
    label: Total mass loss, pre-mix pack (NASA, GSC12070)
    value: 1.88
    unit: '%'
    scope: material
    conditions:
      data_reference: GSC12070
      form: pre-mix pack, as listed
      cure: 24 hours at 25 °C
      test: 125 °C for 24 hours in vacuum (NASA method)
    method: Listed in NASA RP-1124 Rev 3, Section 1 (Adhesives), TML column
    status: ground
    note: Above the listing's own 1.0 percent TML limit; recorded as printed.
    source: nasa-rp1124
    where: Section 1 (Adhesives) listing, PDF page 30, row GSC12070
corrosion:
  - environment: Heating in air (weight loss)
    headline: Weight loss is 0.22 % at 200 °C, 0.39 % at 250 °C and 0.87 % at 300 °C, per the manufacturer datasheet.
    effect: The datasheet lists these weight losses next to a degradation temperature of 412 °C. It prints no test method for them and says its data are a guide only, not guaranteed.
    rating: low
    conditions:
      atmosphere: not printed
      basis: typical values, not guaranteed (datasheet)
    source: epotek-353nd-tds
    where: Physical Properties table, Weight Loss and Degradation Temp rows
  - environment: Vacuum at 125 °C (outgassing)
    headline: The amber-cured row lost 0.81 % of its mass; the pre-mix rows lost 1.83 % to 2.03 %.
    effect: NASA's method heats the sample to 125 °C for 24 hours in vacuum, with a collector held at 25 °C, and records total mass loss (TML) and collected volatile condensable material (CVCM). Rows above the listing's own 1.0 percent screen are recorded as printed.
    rating: moderate
    conditions:
      test: 125 °C for 24 hours in vacuum, collector at 25 °C (NASA method)
      cure: amber row 120 °C; pre-mix rows 24 hours at 25 °C
    source: nasa-rp1124
    where: Section 1 (Adhesives) listing, PDF pages 8 and 30
  - environment: Humid air after the vacuum test (water regained)
    headline: The amber-cured row regained 0.35 % of its mass as water at 25 °C and 50 percent relative humidity.
    effect: NASA's water vapor regained (WVR) is water readsorbed over 24 hours after the vacuum test. The water values for the pre-mix rows are not recorded in this profile.
    rating: low
    conditions:
      exposure: 25 °C, 50 percent relative humidity, 24 hours
    source: nasa-rp1124
    where: Section 1 (Adhesives) listing, PDF page 30, row GSC20704; method text on PDF page 8
  - environment: Ionic residues next to metal contacts
    headline: The datasheet prints a chloride ion content of 329 ppm, but gives no corrosion test.
    effect: The Ion Content line also lists ammonium and potassium levels, which are not recorded here. The sources read give no corrosion result for metals in contact with this adhesive.
    rating: unknown
    conditions:
      test: not printed
    source: epotek-353nd-tds
    where: Physical Properties table, Ion Content row
risks:
  hazards:
    - text: Part A (Epoxy Technology SDS, version 1.1, revised 2/16/2024) is classed under GHS US as skin irritant category 2, skin sensitizer category 1 and aquatic chronic category 2, with the signal word Warning.
      ghs:
        - H315
        - H317
        - H411
      source: epotek-353nd-sds-a
      where: Sections 2.1 and 2.2
    - text: 'Part B (SDS version 2.2, revised 2/16/2024, 3 cc syringe copy) is classed as Danger under GHS US: harmful if swallowed (acute toxicity category 4), severe skin burns (category 1B), serious eye damage (category 1), skin sensitizer (category 1), suspected carcinogen (category 2) and reproductive toxicant (category 1B).'
      ghs:
        - H302
        - H314
        - H317
        - H318
        - H351
        - H360
      source: epotek-353nd-sds-b
      where: Sections 2.1 and 2.2
    - text: The 2014 Part B SDS (revision 1, Purdue copy) gives EU CLP codes H302, H314 and H361d with the signal word Danger, which differs from the 2024 US GHS listing above; both are recorded.
      ghs:
        - H302
        - H314
        - H361d
      source: purdue-353nd-sds-2014
      where: Part B hazard classification block
    - text: 'Transport: the Part A SDS prints UN3082 and the Part B SDS prints UN3267 in section 14.'
      ghs: []
      source: epotek-353nd-sds-b
      where: Section 14, Transport information
  failure_risks:
    - mode: Skin sensitization and chemical burns
      trigger: Skin or eye contact with Part A or Part B, before or after mixing
      consequence: Part A may cause an allergic skin reaction (H317). Part B causes severe skin burns and serious eye damage (H314, H318) under the 2024 SDS.
      severity: high
      source: epotek-353nd-sds-b
      where: Sections 2.1 and 2.2
    - mode: Under-cure
      trigger: A cure shorter or cooler than the recommended 150 °C for 1 hour
      consequence: The datasheet warns that shorter alternative cures 'May not achieve performance properties listed', and says the grade passes NASA's low-outgassing screen only with proper cure.
      severity: moderate
      source: epotek-353nd-tds
      where: Header block (cure table) and Advantages and Suggested Application Notes
    - mode: Outgassing in vacuum
      trigger: Vacuum exposure of a cured joint at 125 °C
      consequence: NASA's listing records 0.81 % total mass loss for the amber-cured row and 1.83 % to 2.03 % for the pre-mix rows.
      severity: moderate
      source: nasa-rp1124
      where: Section 1 (Adhesives) listing, PDF page 30
  handling:
    - text: The datasheet lists a shelf life of 'One year at room temperature' for bulk material and 'Six months at -40°C' for the frozen syringe.
      source: epotek-353nd-tds
      where: Header block, Shelf Life rows
    - text: 'Part A SDS: store in a well-ventilated place and keep cool, at a printed storage temperature of 25 °C.'
      source: epotek-353nd-sds-a
      where: Sections 7.1 and 7.2
    - text: 'Part B SDS: store locked up in a well-ventilated place and keep cool; keep out of reach of children.'
      source: epotek-353nd-sds-b
      where: Sections 2.2 and 7.2
    - text: The datasheet note reads 'TOTAL MASS SHOULD NOT EXCEED 25 GRAMS'.
      source: epotek-353nd-tds
      where: Notes block
    - text: If the product crystallizes in storage, warm the container in an oven until the crystals disappear, as the datasheet advises.
      source: epotek-353nd-tds
      where: Notes block
  mitigations:
    - text: Use the recommended cure of 150 °C for 1 hour (printed as '150°C / 1 Hour'). The datasheet says shorter alternative cures may not reach the listed properties.
      source: epotek-353nd-tds
      where: Header block (cure table)
uses:
  - application: electronics-and-chips
    device: Wafer-to-wafer bonding, MEMS fabrication and flip-chip underfill in semiconductor packaging
    example: The datasheet lists its semiconductor suggested applications as wafer-wafer bonding of CSP, fabrication of MEMs devices and flip chip underfill.
    source: epotek-353nd-tds
    where: Advantages and Suggested Application Notes, semiconductor bullet
  - application: optics-and-cameras
    device: Fiber optic ferrules and active alignment of optics
    example: The product page says the adhesive is 'Designed to meet Telecordia 1221'. The datasheet suggests sealing fiber into ferrules and active alignment of optics.
    source: meridian-353nd-page
    where: Product description; datasheet fiber optic bullet
  - application: electronics-and-chips
    device: Coil impregnation and bonding of ferrite cores and magnets in motors and inductors
    example: The datasheet suggests impregnating and insulating copper coil windings in motors and inductor coils, and bonding ferrite cores and magnets.
    source: epotek-353nd-tds
    where: Advantages and Suggested Application Notes, electronics assembly bullet
supply:
  - subject: Epoxy phenol novolac resin (Part A)
    abundance: 'Not a mineral. The resin is built from petroleum-derived feedstocks: phenol and formaldehyde make a novolak, and epichlorohydrin is then reacted with it to make an epoxy novolak (Wikipedia, Epoxy).'
    producers: []
    critical_lists: []
    substitutes: []
    source: wikipedia-epoxy
    where: Epoxy article, Production and Novolaks sections
  - subject: Imidazole-based curing agent (Part B)
    abundance: No feedstock or production data for the Part B components were found in the sources read. The Part B SDS names the imidazole compounds by CAS number, with the shares printed as ranges.
    producers: []
    critical_lists: []
    substitutes: []
    source: epotek-353nd-sds-b
    where: Section 3.2, Mixtures table
  - subject: EPO-TEK 353ND (manufacturer)
    abundance: Made by Epoxy Technology, Inc., 14 Fortune Drive, Billerica, MA 01821, USA, as printed in SDS section 1.3. No market share or production volume is printed in any source read.
    producers: []
    critical_lists: []
    substitutes: []
    source: epotek-353nd-sds-a
    where: Section 1.3, Supplier
documents:
  - title: EPO-TEK 353ND Technical Data Sheet, rev XXXIII (March 2025)
    type: datasheet
    url: https://products.meridianadhesives.com/storage/downloads/lekanct3nwssjpc0wqjttpu4wstshep5/353nd-rev-xxxiii-new-template.pdf
    year: 2025
  - title: EPO-TEK 353ND Technical Data Sheet, rev XXXI (March 2023), Fiber Optic Center copy of the 4 g heat-cure pack
    type: datasheet
    url: https://media.focenter.com/CMP1007/files/1/EPOTEK353NDHighTemperatureEpoxyHeatCure4g_ET353ND-4G_fiberopticcenter_REV2.pdf
    year: 2023
  - title: EPO-TEK 353ND Part A safety data sheet, version 1.1 (revised 2/16/2024)
    type: sds
    url: https://products.meridianadhesives.com/storage/downloads/ok2ljt7erew7wlt5fhtdd0tbmtd0bxsr/353nd-sds-1.pdf
    year: 2024
  - title: EPO-TEK 353ND Part B safety data sheet, version 2.2 (revised 2/16/2024), Fiber Optic Center copy for the 3 cc pre-mixed frozen syringe
    type: sds
    url: https://media.focenter.com/CMP1007/files/1/EPOTEK353NDHighTemperatureEpoxyHeatCurePreMixedandFrozen3ccSyringe_ET353ND-3CC_SDS_SafetyDataSheet_PartB_fiberopticcenter_REV3.pdf
    year: 2024
  - title: EPO-TEK 353ND Part A and Part B safety data sheets, revision 1 (07/10/2014), Purdue copy
    type: sds
    url: https://www.physics.purdue.edu/primelab/safety/MSDS/SDS/EPO-TEK353ND%20epoxy.pdf
    year: 2014
  - title: Outgassing Data for Selecting Spacecraft Materials, NASA Reference Publication 1124, Revision 3
    type: report
    url: https://ntrs.nasa.gov/api/citations/19940017416/downloads/19940017416.pdf
    year: 1993
gaps:
  - Coefficient of thermal expansion (54 x 10-6 in/in°C below Tg, 206 x 10-6 in/in°C above Tg) is printed in exponent form, so it is left out. Volume resistivity (1.8 x 10^13 Ohm-cm) is also printed in exponent form and is left out.
  - The NASA amber-cured row's cure time prints as 'IH' in the PDF text layer and is not clear enough to record, so only its 120 °C cure temperature is recorded.
  - The NASA listing does not say whether the amber row is the same packaging as the pre-mix rows. The amber row is recorded under the grade name as printed.
  - CVCM and water vapor regained for the three pre-mix NASA rows (GSC12064, GSC12067, GSC12070) are not recorded here; only their total mass loss is.
  - The NASA listing says it contains only materials with a TML of 1.0 percent or less and a CVCM of 0.10 percent or less, but the three pre-mix rows exceed the TML limit. Rows are recorded as printed.
  - EPO-TEK 353ND-T (NASA data reference GSC17696, TML 1.14 %) is a different product code and is not recorded.
  - 'The Part B composition is only partly printed: two imidazole compounds have shares printed as ranges, and a substituted anhydride and a further substituted imidazole are withheld as trade secrets. No single full composition is available.'
  - The 2024 Part A and Part B SDSs print 'No data available' for flash point; the only flash point found is the 93 °C value in the 2014 Purdue copy.
  - No test standard is printed for the hardness, lap shear, die shear, degradation temperature, weight loss or storage modulus values.
  - Storage modulus has no temperature or test method printed, so it is recorded with those conditions marked not printed.
  - Chemical resistance and moisture-absorption values were not found. The product page calls the epoxy 'superior moisture resistance' without a number.
  - The 2026 GHS-update SDS and the Part B bulk-pack SDS listed by the manufacturer were not located, so the Part B SDS recorded here is the 3 cc pre-mixed syringe copy.
  - No supply share, production volume or critical-mineral listing for this grade, its Part A resin or its Part B curing agent was found in any source read. Wikipedia gives feedstock routes only.
  - No space flight, thermal-vacuum or radiation test for EPO-TEK 353ND was found beyond the NASA outgassing listing.
sources:
  epotek-353nd-tds:
    title: EPO-TEK 353ND Technical Data Sheet, High Temperature Epoxy, rev XXXIII (Epoxy Technology, March 2025)
    id: Rev XXXIII, March 2025
    url: https://products.meridianadhesives.com/storage/downloads/lekanct3nwssjpc0wqjttpu4wstshep5/353nd-rev-xxxiii-new-template.pdf
    year: 2025
    kind: datasheet
    license: manufacturer datasheet, linked not reproduced
  epotek-353nd-tds-rev31:
    title: EPO-TEK 353ND Technical Data Sheet, rev XXXI (March 2023), Fiber Optic Center copy
    id: Rev XXXI, March 2023
    url: https://media.focenter.com/CMP1007/files/1/EPOTEK353NDHighTemperatureEpoxyHeatCure4g_ET353ND-4G_fiberopticcenter_REV2.pdf
    year: 2023
    kind: datasheet
    license: manufacturer datasheet, linked not reproduced
  epotek-353nd-sds-a:
    title: EPO-TEK 353ND Part A Safety Data Sheet, version 1.1
    id: Revision date 2/16/2024
    url: https://products.meridianadhesives.com/storage/downloads/ok2ljt7erew7wlt5fhtdd0tbmtd0bxsr/353nd-sds-1.pdf
    year: 2024
    kind: datasheet
    license: supplier SDS, linked not reproduced
  epotek-353nd-sds-b:
    title: EPO-TEK 353ND Part B Safety Data Sheet, version 2.2, 3 cc pre-mixed frozen syringe (ET353ND-3CC), Fiber Optic Center copy
    id: Revision date 2/16/2024; FOC last update 5/5/2026
    url: https://media.focenter.com/CMP1007/files/1/EPOTEK353NDHighTemperatureEpoxyHeatCurePreMixedandFrozen3ccSyringe_ET353ND-3CC_SDS_SafetyDataSheet_PartB_fiberopticcenter_REV3.pdf
    year: 2024
    kind: datasheet
    license: supplier SDS, linked not reproduced
  purdue-353nd-sds-2014:
    title: EPO-TEK 353ND Part A and Part B Safety Data Sheets, revision 1 (Purdue copy)
    id: Revision date 07/10/2014
    url: https://www.physics.purdue.edu/primelab/safety/MSDS/SDS/EPO-TEK353ND%20epoxy.pdf
    year: 2014
    kind: datasheet
    license: supplier SDS, linked not reproduced
  meridian-353nd-page:
    title: EPO-TEK 353ND product page, Meridian Adhesives Group
    id: Product page, qualitative claims only
    url: https://meridianadhesives.com/products/epo-tek-353nd/
    kind: web
    license: manufacturer web page, linked not reproduced
  nasa-rp1124:
    title: Outgassing Data for Selecting Spacecraft Materials, NASA Reference Publication 1124, Revision 3 (Campbell and Scialdone)
    id: NASA RP-1124 Rev 3; NTRS 19940017416
    url: https://ntrs.nasa.gov/api/citations/19940017416/downloads/19940017416.pdf
    year: 1993
    kind: report
    license: NASA public document
  wikipedia-epoxy:
    title: Epoxy, Wikipedia
    id: Epoxy article, Production and Novolaks sections
    url: https://en.wikipedia.org/wiki/Epoxy
    kind: web
    license: CC BY-SA 4.0, linked not reproduced
license: CC-BY-4.0
updated: '2026-11-02'
review:
  status: draft
  method: assistant
  checked_values: 28
  unreachable: 0
  caveats: 8
  note: 'Values read by an AI assistant on 2026-11-02 from the rev XXXIII datasheet PDF, the Part A and Part B SDS PDFs, the 2014 Purdue SDS PDF and the NASA RP-1124 PDF text layer. Caveats: revision differences in viscosity speed and refractive index label, a 2014 flash point not confirmed by the 2024 SDS, and three NASA pre-mix rows above the listing''s own TML limit.'
story:
  recipe:
    line: 'EPO-TEK 353ND is sold as two parts that are mixed and then heat cured. Part A is an epoxy phenol novolac resin. Part B is a curing agent based on imidazole compounds, and a substituted anhydride is also named. The datasheet prints the mix ratio as ''10 : 1'' by weight and the recommended cure as ''150°C / 1 Hour''.'
    parts:
      - name: Epoxy phenol novolac resin (Part A)
        role: Forms the cured network. Novolak epoxies are made by reacting phenol with formaldehyde and then with epichlorohydrin (Wikipedia, Epoxy).
        share_note: Printed as '≥ 60' percent by weight in the Part A SDS, section 3.2
        source: epotek-353nd-sds-a
        where: Section 3.2, Mixtures table
      - name: Imidazole-based curing agent (Part B)
        role: Hardener for the resin. The Part B SDS names two imidazole compounds, with their shares printed as ranges.
        share_note: Shares printed as ranges in the Part B SDS, section 3.2
        source: epotek-353nd-sds-b
        where: Section 3.2, Mixtures table
      - name: Substituted anhydride (Part B, trade secret)
        role: A second hardener class named in the Part B SDS. Its identity is withheld as a trade secret, so it is not identified here.
        share_note: Printed as '<5' percent in the Part B SDS, section 3.2
        source: epotek-353nd-sds-b
        where: Section 3.2, Mixtures table
  risk_groups:
    - title: For people
      lead: Part A is a skin irritant and sensitizer. Part B carries the serious hazards, and the 2014 and 2024 SDSs classify it differently.
      level: 3
      verdict: Part B is Danger (2024 SDS)
      points:
        - label: Part A
          line: Classed under GHS US as skin irritant category 2, skin sensitizer category 1 and aquatic chronic category 2 (H315, H317, H411), with the signal word Warning.
        - label: Part B
          line: 'Classed as Danger in the 2024 SDS: harmful if swallowed, causes severe skin burns and serious eye damage, may cause an allergic skin reaction, is suspected of causing cancer and may damage fertility or the unborn child. The 2014 SDS gives EU CLP codes H302, H314 and H361d.'
        - label: Dust
          line: Harmful dust may be released when the cured material is cut, milled or ground (2024 Part B SDS).
    - title: If it overheats
      lead: The sources read give no thermal runaway or fire test for this grade.
      level: 2
      verdict: Toxic fumes in a fire
      points:
        - label: In a fire
          line: The SDSs say toxic fumes may be released in a fire, and they name no specific decomposition products.
        - label: Flash point
          line: The 2014 SDS prints a flash point of 93 °C for Part B. The 2024 SDSs print 'No data available' for flash point.
    - title: In space
      lead: NASA's outgassing listing is the only space-related record found for this grade.
      level: 1
      verdict: Mass loss in vacuum
      points:
        - label: Mass loss
          line: NASA's 125 °C vacuum test gives 0.81 % total mass loss for the amber-cured row and 1.83 % to 2.03 % for the pre-mix rows.
  why: EPO-TEK 353ND is a two-part high-temperature epoxy made by Epoxy Technology, Inc. in Billerica, Massachusetts, for semiconductor, hybrid and fiber optic assembly. Its datasheet gives a glass transition of at least 90 °C and says the grade passes NASA's low-outgassing standard only with a proper cure. NASA's outgassing compilation lists the grade as an adhesive in four rows, and the amber-cured row shows the lowest total mass loss.
  uses:
    - where: Semiconductor and MEMS packaging
      line: The manufacturer suggests the grade for wafer-to-wafer bonding of chip-scale packages, for making MEMS devices and for flip-chip underfill.
    - where: Fiber optic assembly
      line: The product page says the adhesive is designed to meet Telecordia 1221. The datasheet suggests it for sealing fiber into ferrules and for active alignment of optics.
    - where: Motor and inductor windings
      line: The manufacturer suggests impregnating and insulating copper coil windings in motors and inductor coils, and bonding ferrite cores and magnets.
  can_do:
    - label: Heat
      benchmark: max_service_temp
      value: below 350 °C, intermittent
      line: The manufacturer's suggested operating temperature is below 350 °C for intermittent use. The datasheet gives a degradation temperature of 412 °C.
    - label: Bond strength
      benchmark: lap_shear_strength
      value: more than 2,000 psi
      line: Lap shear is more than 2,000 psi at 23 °C. Die shear is 5,334 psi, printed in the datasheet as at least 15 kg.
    - label: Hardness
      benchmark: shore_d_hardness
      value: 85 Shore D
      line: The cured resin has a Shore D hardness of 85.
    - label: Outgassing
      benchmark: total_mass_loss
      value: 0.81 %
      line: In NASA's 125 °C vacuum test, the amber-cured row loses 0.81 % of its mass. The three pre-mix rows lose 1.83 % to 2.03 %.
    - label: Electrical and optical
      benchmark: dielectric_constant
      value: 3.17 at 1 kHz
      line: The dielectric constant is 3.17 and the dissipation factor is 0.005 at 1 kHz. Transmission is at least 50 % at 550 nm.
  compare: The sources give no ranking of this grade against other epoxies. Within its own records, the amber-cured NASA row has the lowest total mass loss, at 0.81 %, against 1.83 % to 2.03 % for the pre-mix rows. The NASA rows and the datasheet use different cures and packaging, so the two sets should not be read as one. No other epoxy in this profile set has the same test data, so the table compares the grade with its own rows only.
  compare_rows:
    - label: Total mass loss, amber-cured row
      benchmark: total_mass_loss
    - label: Glass transition temperature
      benchmark: glass_transition_temperature
    - label: Dielectric constant at 1 kHz
      benchmark: dielectric_constant
  handling:
    - 'Bulk product: the datasheet lists a shelf life of ''One year at room temperature''. The frozen syringe version lasts ''Six months at -40°C''.'
    - Keep containers closed when not in use. If the product crystallizes, warm the container in an oven until the crystals disappear, as the datasheet advises.
    - The datasheet note reads 'TOTAL MASS SHOULD NOT EXCEED 25 GRAMS'.
    - Wear gloves and eye protection. Part A can cause an allergic skin reaction, and Part B can cause severe skin burns and serious eye damage (2024 SDSs).
    - 'Part B: store locked up in a well-ventilated place and keep cool (2024 Part B SDS, section 7).'
  good_for:
    - High-temperature joints that must stay below 350 °C in intermittent use, as the manufacturer suggests.
    - Semiconductor, MEMS and fiber optic assembly, which are the uses the datasheet names.
    - Vacuum hardware that must pass a low-outgassing screen, with proper cure (the datasheet makes this claim).
  watch_out:
    - 'Cure matters: the recommended cure is printed as ''150°C / 1 Hour'', and the datasheet warns that shorter cures ''May not achieve performance properties listed''.'
    - 'Outgassing varies by row and cure: the NASA rows span 0.81 % to 2.03 % total mass loss.'
    - 'Part B is hazardous: the 2024 SDS classes it as Danger, with H360 (may damage fertility or the unborn child).'
    - The datasheet says its data are a guide only and 'not guaranteed'.
  verdict: EPO-TEK 353ND is a well-documented high-temperature epoxy, with a printed glass transition of at least 90 °C and a Shore D hardness of 85. Its low-outgassing record depends on proper cure, its Part B hazards are serious, and the sources give no production or supply data for the grade.