What is 350 cSt silicone oil used for?
Mold release, paint polishes and plastic-care products, damping, and personal-care emolliency — the general-purpose PDMS grade. At 350 cSt the film is durable and low-migration: it stays where you put it, at the cost of slower spreading than the 50–100 cSt grades. Typical spec: 0.967 specific gravity, > 260 °C flash point (per TDS).
Dimethicone- ▸ Mold release for rubber, plastic and metal parts and digital-printing equipment — durable, persistent film
- ▸ Paint polishes, paint conditioners and plastic / vinyl care products — gloss and water repellency
- ▸ Incidental-contact lubricant and defoamer duty in processing and packaging plants — food-plant use requires a registered grade; confirm at RFQ
- ▸ Heat-transfer / thermal-bath oil and heat-resistant lubricant for polymer parts
- ▸ Personal-care emollient and barrier in creams, lotions, conditioners and makeup
Don’t see your viscosity? We can custom-formulate silicone fluid to your target cSt — tell us your spec.
Not sure which grade? Silicone oil viscosity guide (5 to 500,000 cSt) · All silicone oils
- ▸ Safety Data Sheet (SDS) PDF · SDS
- ▸ Technical Data Sheet (TDS) PDF · TDS
- ▸ Typical Certificate of Analysis (CoA) PDF · COA
Values shown are typical for the current commercial grade. A lot-specific Certificate of Analysis accompanies every shipment; the grade-specific SDS is available on request.
Mid- and high-viscosity polydimethylsiloxane fluids (>= 5 cSt) are reported as not meeting GHS hazard-classification criteria. The grade-specific SDS governs. A full SDS is supplied with every shipment and on request; hazard status is confirmed against the grade-specific SDS.
Cross-reference: comparable to XIAMETER PMX-200 Silicone Fluid 350 cSt (a Dow product): the same linear polydimethylsiloxane chemistry at the same nominal viscosity. RawSource is independent of Dow; confirm grade-critical specs against the RawSource TDS and lot CoA.
Silicone Oil 350 cSt is the general-purpose grade, the one most often specified for paint polishes and plastic care. Its higher mid viscosity gives a durable, persistent release film with little migration, so it is used for mold release, paint polishes and plastic-care products, damping, and personal-care emolliency.
Reviewed and updated July 2026 by the RawSource technical team.
Silicone oil 350 cSt is a polydimethylsiloxane (dimethicone, CAS 9006-65-9) fluid with a kinematic viscosity of 350 centistokes at 25 °C, the general-purpose grade for release, damping, and formulation work.
Silicone Oil 350 cSt: Key Figures
- 300–1,050 cSt at 25 °C: the dimethylpolysiloxane viscosity window FDA defines for food-processing defoaming agents in 21 CFR 173.340 (2024 edition). The 350 cSt grade sits inside it.
- 10 parts per million: the ceiling 21 CFR 173.340 places on dimethylpolysiloxane residues in finished food, and zero in milk, per the same FDA rule (2024 edition).
- 3% general duty: the US import rate on silicones in primary forms under subheading 3910.00.00 of the Harmonized Tariff Schedule (USITC, 2026).
- Flash point above 260 °C (open cup): with specific gravity 0.967 at 25 °C and volatile loss under 2% after 1 hour at 150 °C, typical values from the RawSource technical data sheet (July 2026).
- 7,656 reported uses: dimethicone filings in FDA’s Voluntary Cosmetic Registration Program in 2021, up from 1,659 in 1998, per the CIR amended safety assessment (2021).
Frequently Asked Questions
What is silicone oil 350 cSt used for?
350 cSt silicone oil (dimethicone / PDMS) is the general-purpose grade: mold release for rubber, plastic and metal parts, paint polishes and plastic-care products, damping, and personal-care emolliency. Its mid-high viscosity gives a durable, low-migration film — it stays where you put it, at the cost of slower spreading than the 50–100 cSt grades.
Is 350 cSt silicone oil the same as dimethicone or PDMS?
Yes. Silicone oil, silicone fluid, dimethicone and PDMS all name the same linear polydimethylsiloxane (CAS 9006-65-9) — 350 cSt is the viscosity grade, not a different chemistry. Because PDMS is a polymer, properties are reported per grade rather than as one fixed molecular weight.
Is 350 cSt silicone oil flammable?
No. With a flash point of > 260 °C (per TDS), the 350 cSt grade sits far above GHS flammable-liquid cut-offs, and mid- and high-viscosity PDMS is not otherwise GHS-classified. Only the volatile sub-5 cSt silicone fluids are flammable. The grade-specific SDS ships with every order.
What is the CAS number for silicone oil 350 cSt?
Silicone oil 350 cSt carries CAS 9006-65-9, with repeating-unit formula (C2H6OSi)n; some manufacturers list the equivalent trimethylsiloxy-terminated PDMS under CAS 63148-62-9. The cSt figure is the viscosity grade, not a separate substance — all dimethicone grades share the same CAS registry.
What packaging is 350 cSt silicone oil supplied in?
Bulk only: 55-gallon drums, 275-gallon IBC totes, and 5-gallon pails, with pallet and full-truck quantities quoted on request. A lot-specific Certificate of Analysis accompanies every shipment; the grade SDS is available on request. Submit an RFQ with your target volume and packaging.
What does cSt mean in silicone oil?
cSt stands for centistokes, the standard unit of kinematic viscosity; one centistoke equals one square millimeter per second (mm²/s), an exact conversion listed in NIST SP 811. Silicone oil grade names state nominal viscosity at 25 °C, so 350 cSt names the grade rather than a lot measurement. Because kinematic viscosity is what a capillary viscometer reads, the number compares directly across manufacturers. Specify the centistoke grade on the RFQ; the CoA verifies each lot against it.
Is higher cSt thicker or thinner?
Thicker. Centistokes measure kinematic viscosity, so a higher cSt number means a slower-flowing, heavier-bodied silicone oil. On the PDMS ladder, 50 and 100 cSt grades spread and atomize quickly, 350 cSt lays down a durable low-migration film, and 1,000 cSt and above run to damping and heavy release duty. Chemistry is identical across the ladder, so buyers select on film persistence, pump and metering behavior, and dose rate.
What is silicone oil 350 cSt food grade?
Food-grade 350 cSt silicone oil is dimethylpolysiloxane certified to the FDA defoaming-agent specification in 21 CFR 173.340: viscosity 300 to 1,050 centistokes at 25 °C, refractive index 1.400 to 1.404, and defined purity criteria, with residues capped at 10 parts per million in finished food and zero in milk. The 350 cSt viscosity sits inside that window, so the grade qualifies once a lot is certified against the full specification. Food grade is a lot-level certification, not a viscosity property; state the requirement on your RFQ.
What is the specification for silicone oil 350 cSt?
Typical values run: nominal viscosity 350 cSt at 25 °C, specific gravity 0.967, refractive index 1.405, open-cup flash point above 260 °C, and volatile loss under 2% after one hour at 150 °C, per the RawSource technical data sheet (July 2026). These are typical production values rather than a sales specification; the lot-specific Certificate of Analysis governs every shipment. The TDS and a sample CoA are posted in the documents section of this page.