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Cast Silicone ESD-COND

Additive grade

also RTV

Carbon-black or silver-filled grade for EMI gaskets, contact pads and static-dissipative seals.

Urethane castingStandard cost $$

Values for the ESD-COND condition

Other Cast Silicone grades and fills

Cast Silicone is listed in 15 conditions; see the grade overview at Cast Silicone.

Compare all 15 grades and fillsHide
Grade · open for datasheetBest forYield MPaTensile MPaElong. %Hardness
Silicone foam
Blown low-density cast silicone for thermal/acoustic insulation and compliant compression seals.—115015 Shore A
Ultra-soft cast silicone
Gel-like soft grade for skin-like effects, cushioning pads and delicate lifecasting.—260010 Shore A
Thermally conductive cast silicone
Alumina/boron-nitride filled potting or gap-pad grade for heat transfer with electrical insulation.—312055 Shore A
Soft cast silicone
Soft, highly conformable grade for deep-undercut molds and soft-touch prototypes.—355020 Shore A
ESD-CONDThis page
Electrically conductive / ESD cast silicone
Carbon-black or silver-filled grade for EMI gaskets, contact pads and static-dissipative seals.—415060 Shore A
Tin-cure (condensation-cure) cast silicone
Cheaper, inhibition-tolerant mold rubber; higher shrinkage, alcohol by-product and shorter shelf/mold life.—438035 Shore A
Optically clear cast silicone
Water-clear unfilled/low-filler formulation for lenses, light guides, encapsulation and display parts.—435040 Shore A
Soft mold-making grade
Most common mold-making hardness: easy demolding of detailed or undercut masters.—445030 Shore A
Flame-retardant cast silicone
Filled/FR-additive formulation for electrical potting, rail and enclosure seals requiring V-0.—525050 Shore A
Shore A 40Default
General-purpose cast silicone
Balanced default: enough stiffness for stable mold walls and gaskets, still easily flexed.—540040 Shore A
Platinum-cure (addition-cure) cast silicone
Pick for near-zero shrinkage, no cure by-products, long mold life and medical/food compliance; sensitive to sulfur/tin/latex inhibition.—645040 Shore A
Medium-hard cast silicone
Choose for seals and pads needing better shape retention and lower deflection under load.—735011 Shore D
Hard cast silicone
Stiffer grade for load-bearing gaskets, rollers, bushings and rigid mold shells.—830016 Shore D
High-hardness cast silicone
Hardest common cast grade: dimensional stability and wear resistance where flexibility is secondary.—925022 Shore D
Extra-hard cast silicone
Niche grade for stiff pads, wear strips and rigid inserts; low elongation, higher compression set.—918030 Shore D

What is Cast Silicone ESD-COND?

Cast Silicone ESD-COND is Cast Silicone in the ESD-COND grade — carbon-black or silver-filled grade for EMI gaskets, contact pads and static-dissipative seals. Cast Silicone ESD-COND has a tensile strength of 4 MPa (0.508 ksi), weaker than 100% of silicone grades. Elongation at break is 150% and the elastic modulus is 0.01 GPa (7.25×10⁻⁴ Msi). Cast Silicone ESD-COND has a density of 1.25 g/cm³ (0.0452 lb/in³), heavier than 100% of silicone grades. Its glass-transition temperature is -122°C (-188 °F). Shore A 40 is the default condition FabDigit quotes; ESD-COND is available on request or by drawing note.

Advantages

  • Conducts heat well — 0.5 W/m·K (0.289 BTU/hr·ft·°F), better than 150% of silicone grades

Limitations

  • Limited ductility — 150%, worse than 100% of silicone grades
  • Limited formability — 65/100, worse than 100% of silicone grades

Cast Silicone ESD-COND properties

Typical room-temperature values for Cast Silicone ESD-COND; 16 are specific to this condition. Other listed values are Cast Silicone reference data and may not represent this condition. Bars are the position among silicone grades.

Physical5

Cast Silicone ESD-COND has a density of 1.25 g/cm³ (0.0452 lb/in³), heavier than 100% of silicone grades. Its glass-transition temperature is -122°C (-188 °F).

Density1.25 g/cm³0.05 lb/in³
Glass Transition (Tg)-122°C-188 °F
Water Absorption (24 h)0.3%
Water Absorption (Saturation)1%
Refractive Index1.41

Mechanical7

Cast Silicone ESD-COND has a tensile strength of 4 MPa (0.508 ksi), weaker than 100% of silicone grades. Elongation at break is 150% and the elastic modulus is 0.01 GPa (7.25×10⁻⁴ Msi).

Elastic (Young's) Modulus0.01 GPa7.25×10⁻⁴ Msi
Poisson's Ratio0.49
Tensile Strength (Ultimate)4 MPa0.51 ksi
Elongation at Break150%
Hardness, Shore A60 Shore A
Tear Strength10 kN/m57.1 lbf/in
Compression Set (22 h, 70 °C)20%

Thermal8

Cast Silicone ESD-COND is rated for continuous service to 180°C (356 °F). It conducts heat at 0.5 W/m·K (0.289 BTU/hr·ft·°F), better than 150% of silicone grades. Thermal expansion is 270 µm/m·K (150 µin/in·°F).

Thermal Conductivity0.5 W/m·K0.29 BTU/hr·ft·°F
Specific Heat Capacity1,300 J/kg·K0.31 BTU/lb·°F
Thermal Expansion (CTE, 20–100 °C)270 µm/m·K150 µin/in·°F
Max Service Temperature (continuous)180°C356 °F
Min Service Temperature-55°C-67 °F
Flammability (UL 94)HB (standard grades); V-0 achievable with FR-filled formulations
Limiting Oxygen Index28%
Max Service Temperature (short-term)260°C500 °F

Electrical7

Cast Silicone ESD-COND is an electrical insulator with a dielectric strength of 20 kV/mm (508 V/mil) and a resistivity of 0.1 Ω·m.

Electrical Resistivity0.1 Ω·m3,937,000 µΩ·in
Dielectric Strength20 kV/mm508 V/mil
Dielectric Constant (1 MHz)3
Dissipation Factor (1 MHz)0.001
Volume Resistivity10 Ω·cm
Surface Resistivity1×10¹⁵ Ω
Comparative Tracking Index (CTI)600 V

Chemical & Environmental3

Corrosion resistance is very good (80/100), better than 50% of silicone grades. UV resistance is excellent.

Corrosion ResistanceVery good80/100
UV / Weathering ResistanceExcellent96/100
Chemical Resistance SummaryExcellent against water, ozone, UV, oxidising chemicals, dilute acids/bases, alcohols and vegetable oils; swells badly in aromatic/chlorinated solvents, gasoline and non-polar oils; attacked by concentrated acids/alkalis, high-pressure steam and hydrofluoric acid.

Sustainability4

Producing a kilogram of Cast Silicone ESD-COND takes about 130 MJ of energy and emits 7 kg of CO₂ — less than 100% of silicone grades. Typical recycled content is 0%.

Embodied Energy (primary production)130 MJ/kg55,890 BTU/lb
Embodied Carbon (primary production)7 kg CO₂/kg
Embodied Water300 L/kg35.9 gal/lb
Typical Recycled Content0%

Manufacturability5

Cast Silicone ESD-COND's machinability is poor (20/100, worse than 100% of silicone grades); formability good (65/100).

MachinabilityPoor20/100
Formability (cold)Good65/100
PolishabilityVery good70/100
Mold Shrinkage0.3%
Mold Temperature (typ.)25°C77 °F

Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.

Working with Cast Silicone ESD-COND

Is Cast Silicone easy to machine?

Rarely machined; cured parts are best waterjet, laser or die cut, or frozen/backed before knife trimming — flash is removed by tumbling or trimming.

Can Cast Silicone be welded?

Not weldable; join by uncured silicone adhesive, self-bonding tape or platinum-cure over-molding onto a freshly cured, primed surface.

Can Cast Silicone be formed, bent or molded?

Two-part mix by weight, vacuum degas at ~29 inHg, pour in a thin stream to avoid entrapment; RT cure 4–24 h plus optional 1–4 h post-cure at 60–150 °C for full properties and low volatiles.

What surface finishes work on Cast Silicone?

Surface replicates the mold finish exactly; pigment in the mix rather than painting — paint only adheres via silicone-compatible primers, and plasma or primer treatment is needed for bonding.

Cast Silicone chemical composition (wt %)

Limits by weight percent from the governing specification, written the way the spec states them — a single maximum for impurities, a range for alloying elements, and the base element as balance. Nominal is the typical mid-range value.

ElementSpec limit (wt %)Nominal
silica filler (fumed / ground quartz)reinforcing and extending filler; sets hardness15 – 4030
SiH crosslinker (methylhydrogensiloxane)addition-cure systems0.5 – 52
platinum catalyst (Karstedt)Pt-cure only; tin octoate in condensation systems5×10⁻⁴ – 0.010
pigment / inhibitor / additives0 – 31
polydimethylsiloxane (vinyl-terminated Pbase polymer≥ 55 (balance)—

Cast Silicone ESD-COND — frequently asked

What is Cast Silicone ESD-COND used for?

Cast Silicone ESD-COND is typically used for medical prototypes, seals and kitchenware. In short: platinum-cure silicone; high temp and biocompatible.

What is the tensile strength of Cast Silicone ESD-COND?

Cast Silicone ESD-COND has a typical tensile strength of 4 MPa (0.508 ksi) — weaker than 100% of silicone grades. Strength varies by condition: see the 15 listed tempers.

Is Cast Silicone ESD-COND easy to machine?

Not especially — machinability is rated poor (20/100, worse than 100% of silicone grades). Rarely machined; cured parts are best waterjet, laser or die cut, or frozen/backed before knife trimming — flash is removed by tumbling or trimming.

Can Cast Silicone ESD-COND be welded?

Not weldable; join by uncured silicone adhesive, self-bonding tape or platinum-cure over-molding onto a freshly cured, primed surface.

What surface finishes work on Cast Silicone ESD-COND?

Surface replicates the mold finish exactly; pigment in the mix rather than painting — paint only adheres via silicone-compatible primers, and plasma or primer treatment is needed for bonding.

Can Cast Silicone ESD-COND be formed, bent or molded?

Two-part mix by weight, vacuum degas at ~29 inHg, pour in a thin stream to avoid entrapment; RT cure 4–24 h plus optional 1–4 h post-cure at 60–150 °C for full properties and low volatiles.

What is the maximum service temperature of Cast Silicone ESD-COND?

Cast Silicone ESD-COND is rated for continuous use to about 180°C (356 °F), and briefly to 260°C. Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.

Can FabDigit make parts in Cast Silicone ESD-COND?

Yes — Cast Silicone ESD-COND is available for urethane casting with instant online pricing. Upload a STEP file to get a price and a DFM check.

Sources

  1. ASTM D412 / D624 / D2240 / D395 — rubber tensile, tear, hardness, compression set — ASTM International (2022)
  2. Engineered Materials Handbook Vol. 2: Engineering Plastics / Elastomers — ASM International (1988)
  3. Mold Star & Dragon Skin platinum silicone technical bulletins — Smooth-On (2024)
  4. ELASTOSIL / SILPURAN RTV-2 silicone rubber datasheets — Wacker Chemie AG (2024)
  5. KE-series RTV silicone rubber product guide — Shin-Etsu Chemical (2023)

Property data is compiled from published supplier and standards handbooks and normalised for comparison. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.