Dia 1mm 2mm 3mm 4mm 5mm-30mm Silicone Rubber Solid Round Sealing Strip Gasket #s

KOEED · Sealing & Gasketing · Silicone Cord Stock · In stock

What Is the Silicone Rubber Solid Round Sealing Strip?

This is solid round cross-section silicone rubber cord stock, offered in a wide range of diameters from 1 mm up to 30 mm and in continuous lengths of 1, 2, 3, 5, and 10 meters per roll. Unlike hollow tubing or D-profile weatherstrip, this is a fully dense, void-free round profile — meaning it compresses uniformly under a clamping load and recovers its original shape when the load is removed (assuming compression does not exceed the material's compression-set limit). The material is a peroxide-cured or platinum-cured silicone elastomer that maintains flexibility from approximately -60 degrees C to +200 degrees C without turning brittle or melting, making it suitable for both cryogenic and autoclave-temperature sealing applications.

In short: If you need to make a custom O-ring, gasket, or face seal for an irregularly-shaped flange, enclosure lid, or vessel door — and you need the material to handle temperature extremes, UV exposure, or incidental food contact — this solid round silicone cord, cut to length and joined at the ends, is the universal sealing solution that off-the-shelf gaskets cannot match.

Why Silicone Cord Stock Instead of a Pre-Cut Gasket

1. Infinite Diameter Flexibility — One SKU Covers Any Groove Size

What it means: With 21 diameter options — from hair-thin 1 mm cord for electronics enclosure face seals to chunky 30 mm cord for large vessel manway gaskets — you select the diameter that matches your groove width or the gap you need to fill.
Why it matters: A pre-cut gasket is specific to one flange pattern. If your equipment has an odd-sized inspection port, a non-standard dovetail groove, or a rectangular lid that nobody stocks a gasket for, cord stock lets you create exactly the seal geometry you need by cutting to length and butt-joining the ends with a dot of RTV silicone adhesive.
Result: One purchase solves one-off sealing problems that would otherwise force a custom gasket order with a multi-week lead time and a minimum order quantity.

2. Silicone's Thermal and Chemical Envelope

What it means: Silicone rubber operates continuously at 200 degrees C (intermittent to 230 degrees C) and stays flexible down to -60 degrees C. It resists degradation from UV light, ozone, and atmospheric moisture — it does not chalk, crack, or stiffen like EPDM or nitrile after years of outdoor exposure.
Why it matters: If your sealing application sits on a rooftop enclosure in full sun, inside an autoclave door cycling between steam and vacuum, or on a freezer door gasket at -40 degrees C, silicone is one of the few elastomers that handles all three thermal regimes without switching materials.
Result: Standardize on one cord stock for all your facility's non-oil-contact sealing needs — from oven doors to freezer lids to weather-sealed electrical cabinets.

3. Low Compression Set = Long Service Between Re-Torques

What it means: Compression set is the percentage of original thickness that a gasket fails to recover after being clamped for an extended period at temperature. A low compression-set silicone (typically 5-15 percent after 22 hours at 175 degrees C per ASTM D395) means the cord retains its rebound force over time rather than flattening into a hard, leak-prone wafer.
Why it matters: Gaskets that take a permanent compression set lose bolt preload — the flange bolts effectively loosen as the gasket thins, and the joint starts leaking. A low-set material means you are not re-torquing flange bolts every 500 hours of operation.
Result: Longer maintenance intervals, fewer unscheduled shutdowns for weep-leak repairs.

Available Diameters and Lengths

Select your required diameter and length from the product variants above. The diameter is the round cross-section measurement of the solid cord. The length is the total continuous length per roll.

Key Specifications

Silicone cord hardness, tensile strength, and cure type may vary slightly between diameter batches. This listing is for general industrial-grade solid round silicone cord. If your application requires specific FDA, USP Class VI, or ISO 10993 biocompatibility certification, please specify this in your RFQ so we can confirm certified stock availability.

Practical Applications Across Industries

• Custom O-Ring Fabrication: Cut cord to length, join ends with cyanoacrylate or RTV silicone, and seat in an O-ring groove of any diameter — ideal for large-diameter flange seals where a molded O-ring would be prohibitively expensive or unavailable
• Electrical Enclosure Face Seals: Lay cord into a dovetail or rectangular groove machined into the enclosure lid or body — the silicone compresses to form an IP65/IP66 dust-and-water seal when the lid is closed onto the cord
• Laboratory & Medical Equipment: Autoclave door gaskets, incubator seals, centrifuge lid seals, and lyophilizer door gaskets — applications requiring repeated high-temperature sterilization cycles without gasket degradation
• Food Processing Machinery Seals: Flange gaskets for mixer bowls, hopper lids, and inspection hatches on food-grade equipment (confirm platinum-cured / FDA-compliant variant)
• Vacuum Chamber Lids: A properly-sized round cord in a trapezoidal groove makes an excellent vacuum face seal — silicone's low outgassing rate (compared to nitrile or neoprene) is advantageous in moderate-vacuum applications down to 10^-3 mbar
• Weather Sealing for Outdoor Equipment: CCTV camera housing lids, outdoor electrical junction boxes, solar inverter enclosures, and telecom cabinet door seals — silicone does not chalk or crack after years of UV exposure
• DIY / Prototyping / Repair: Replacing a torn gasket on a vintage espresso machine boiler lid, sealing a custom 3D-printed enclosure, or replacing the perished cord on a classic car's windshield washer reservoir cap

Frequently Asked Questions

"How do I choose the right diameter for my O-ring groove?"

As a rule of thumb: the cord diameter should be 10-25 percent larger than the groove depth to ensure adequate compression (typically 15-25 percent squeeze for static face seals). For example, a groove 3 mm deep calls for approximately 3.5 to 4 mm diameter cord. The groove width should be 1.1 to 1.3 times the cord diameter to allow the cord to fill the groove without extruding sideways. If you are replacing a known O-ring, measure the cross-section of the old O-ring (not the overall outer diameter) — order the nearest matching cord diameter. For non-standard grooves, email your groove dimensions and we can recommend the diameter.

"Can this silicone cord handle contact with oil, diesel, or hydraulic fluid?"

Silicone rubber has poor resistance to hydrocarbon oils, fuels, and most petroleum-based hydraulic fluids — it swells significantly and loses mechanical strength on prolonged contact. For oil-contact sealing, nitrile (NBR), fluorocarbon (FKM/Viton), or PTFE cord stock is the correct material choice. Silicone is excellent for air, water, steam, and mild chemical environments — but keep it away from oil. If your application involves both high temperature AND oil exposure, consider fluorosilicone (FVMQ) cord stock — contact us for availability.

"I need a continuous gasket around a rectangular lid — how do I join the ends of the cord?"

The most reliable method for a static face seal is to cut the cord ends square (clean, perpendicular cut with a razor blade), apply a small dot of room-temperature-vulcanizing (RTV) silicone adhesive to both cut faces, press them together, and allow the adhesive to cure for 24 hours before installing the gasket. The resulting joint has similar mechanical properties to the cord itself. For applications where the joint must not be a weak point (vacuum seals, high-pressure steam), a one-piece molded gasket is preferable — but for general industrial seals and weather stripping, the butt-joined cord works reliably.

"What is the difference between solid round cord and hollow silicone tubing for sealing?"

Solid round cord compresses with rising force as you tighten the flange — it resists compression and pushes back, maintaining seal contact pressure. Hollow tubing collapses easily under low clamping force (good for low-closure-force lids and doors) but bottoms out and loses rebound once the walls touch. For industrial flange gaskets with multiple bolts providing high clamping force, solid cord is the right choice. For a lightweight access panel with a few thumb-screws, hollow tubing may seal better because it requires less force to compress. This listing is solid round cord — it will resist compression and maintain long-term rebound.

"Does KOEED supply this cord in other profiles — square, rectangular, D-shape, or custom extrusions?"

This listing covers the solid round profile in diameters 1-30 mm. We can also source square-profile silicone cord, rectangular strip, D-profile weatherseal, and P-profile bulb seals from our supplier network. If you need a profile that is not listed, email the cross-section drawing or a photo of the existing seal to Moritta@KOEED.COM and we will quote the matching profile and material.

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