Extruded Fiberglass Sleeve
Extruded Fiberglass Sleeve is built from Extruded fiberglass. It is a non-shrink sleeve you slip over the part; it stays in place by fit and friction, with no heating step. Buyers spec it for Electrical appliance insulation sleeving — the typical call is a sized part that stays put through vibration, thermal cycling and field handling. Below is the spec table, the size matrix we keep in stock, and the selection notes our engineering team uses when a purchaser sends a cable or component drawing.
Specification
| Material | Extruded fiberglass |
|---|---|
| Shrink ratio | Non-shrink |
| Wall type | Smooth round tube |
What it is and how it recovers
Extruded Fiberglass Sleeve is a braided or wrapped sleeve that goes on by sliding. It holds by friction and the spring of the weave, so there is no recovery step and no heat. Because the body is Extruded fiberglass, it keeps its insulation and protection through handling and thermal cycling. For procurement this matters: the part you receive is reusable on the bench, but once installed it stays put for the life of the assembly.
Where Extruded Fiberglass Sleeve is used
Primary applications: Electrical appliance insulation sleeving.
How to select the right size
Specifying Extruded Fiberglass Sleeve is mostly about matching three numbers to the part you are covering:
- Recovered vs. supplied diameter. Pick the supplied (expanded) ID at least Non-shrink× the object's largest diameter so the sleeve slides on, then confirm the recovered ID grips it. When in doubt, size up one step rather than forcing a tight fit.
- Wall and adhesive. Thin wall for tight harness bundles; medium/thick wall or adhesive-lined (dual-wall) where you need environmental sealing or abrasion resistance. We keep both in stock.
Common Failure Modes & How to Prevent Them
Drawing on field reports and our engineering team's experience, these are the most common issues installers and buyers report when working with Extruded Fiberglass Sleeve. Each entry shows the symptom, the root cause, and the fix we recommend on the bench and in the field.
It wore through at a sharp corner
An automotive note: "mounted at sharp edges in the engine bay, constant friction - cracking in a short time."
Root cause: A thin, uncoated braid has little abrasion resistance and vibration rubs it through.
Fix: Use a silicone-coated or double-layer braided sleeve, route it clear of edges, and clip it down. For hot zones, vermiculite-coated glass fibre takes molten splash that plain braid won't.
Molten splash burned a hole
A plant reported: "a spark of molten metal went straight through the sleeve."
Root cause: Plain glass fibre without a high-temp coating fails under molten splash.
Fix: Use a vermiculite-coated or high-density sleeve (the Dennis-type thermal sleeve) where weld splatter or molten metal is present. That coating is what stops the burn-through.
The cut end unravelled
"We cut it and the braid opened up along the harness."
Root cause: Braided glass fibre has no self-edge; a cut end frays.
Fix: Cut with a hot knife or melt-seal the end, or use a pre-expanded, bound-end sleeve. A sealed end stays put through vibration.
The rating on the box didn't match the job
A buyer found: "the silicone coat is rated lower than the base glass, so the sleeve isn't as hot as I thought."
Root cause: The coating, not the glass, often sets the working limit; base glass can take ~500 C but the coating lowers it.
Fix: Read the coated rating, not the fibre rating. Size the sleeve to the actual surface temperature plus margin, and pair it with primary insulation where voltage is present.
It is not the insulation
"I treated the sleeve as the insulation and the tester failed."
Root cause: A textile or braided sleeve is mechanical protection, not a primary dielectric.
Fix: Keep the wire's own insulation intact and use the sleeve for heat and abrasion on top. Don't rely on a sleeve alone for low- or high-voltage isolation.
Kapton is brilliant but edge-fragile
"Polyimide-fiberglass is great until the edge nicks."
Root cause: Polyimide film cuts cleanly but a nick can propagate.
Fix: Use polyimide-fiberglass where its temperature and dielectric shine, and protect the cut edges. It earns its cost in tight, hot, high-dielectric spots.
Common Failure Modes & How to Prevent Them
Drawing on field reports and our engineering team's experience, these are the most common issues installers and buyers report when working with Extruded Fiberglass Sleeve. Each entry shows the symptom, the root cause, and the fix we recommend on the bench and in the field.
It wore through at a sharp corner
An automotive note: "mounted at sharp edges in the engine bay, constant friction - cracking in a short time."
Root cause: A thin, uncoated braid has little abrasion resistance and vibration rubs it through.
Fix: Use a silicone-coated or double-layer braided sleeve, route it clear of edges, and clip it down. For hot zones, vermiculite-coated glass fibre takes molten splash that plain braid won't.
Molten splash burned a hole
A plant reported: "a spark of molten metal went straight through the sleeve."
Root cause: Plain glass fibre without a high-temp coating fails under molten splash.
Fix: Use a vermiculite-coated or high-density sleeve (the Dennis-type thermal sleeve) where weld splatter or molten metal is present. That coating is what stops the burn-through.
The cut end unravelled
"We cut it and the braid opened up along the harness."
Root cause: Braided glass fibre has no self-edge; a cut end frays.
Fix: Cut with a hot knife or melt-seal the end, or use a pre-expanded, bound-end sleeve. A sealed end stays put through vibration.
The rating on the box didn't match the job
A buyer found: "the silicone coat is rated lower than the base glass, so the sleeve isn't as hot as I thought."
Root cause: The coating, not the glass, often sets the working limit; base glass can take ~500 C but the coating lowers it.
Fix: Read the coated rating, not the fibre rating. Size the sleeve to the actual surface temperature plus margin, and pair it with primary insulation where voltage is present.
It is not the insulation
"I treated the sleeve as the insulation and the tester failed."
Root cause: A textile or braided sleeve is mechanical protection, not a primary dielectric.
Fix: Keep the wire's own insulation intact and use the sleeve for heat and abrasion on top. Don't rely on a sleeve alone for low- or high-voltage isolation.
Kapton is brilliant but edge-fragile
"Polyimide-fiberglass is great until the edge nicks."
Root cause: Polyimide film cuts cleanly but a nick can propagate.
Fix: Use polyimide-fiberglass where its temperature and dielectric shine, and protect the cut edges. It earns its cost in tight, hot, high-dielectric spots.
Frequently asked questions
Why use Extruded Fiberglass Sleeve instead of heat-shrink tubing?
Heat-shrink polyolefin degrades above roughly 125 °C. This Extruded fiberglass sleeve holds its rated temperature range continuous, so it survives engine-bay radiant heat, exhaust proximity and industrial ovens that would destroy tubing.
Can I install it without taking the harness apart?
Yes — it is a slip-on sleeve, so you can route it over connectors, bundles and assembled looms without unplugging anything. Heat shrink, by contrast, must be threaded on before termination.
How does it protect against abrasion and flexing?
The braid/woven Extruded fiberglass structure absorbs vibration and resists cut-through and abrasion far better than thin-wall tubing, which is why it is used on moving harnesses and cable trays.
Is it the right choice versus a silicone or fiberglass option?
For pure high heat, fiberglass/silicone-coated grades win; for flexibility and bundling, textile/braided sleeves win. Tell us the temperature, motion and exposure and we match the construction.
What certifications back it ()?
Compliance is ; certificates supplied per batch. For a bid we align documentation to your market.
What sizes and colours are available?
We keep a range of IDs and can supply custom cut lengths and colours (including high-visibility) for production lines; send the bundle OD and we size it.
Will a plain glass sleeve take molten splash?
No - use a vermiculite-coated or high-density sleeve where weld splatter or molten metal is present.
How do I stop the cut end fraying?
Cut with a hot knife or melt-seal the end, or use a bound-end pre-expanded sleeve.
Is the sleeve the insulation?
No - it is mechanical and heat protection. Keep the wire's own insulation and add heat shrink at joints for isolation.
What temperature can it take?
Read the coated rating, not the glass rating. The coating usually sets the working limit.
Request a quote for Extruded Fiberglass Sleeve
Tell us the inner diameter, wall type, length and quantity you need, plus the voltage class and environment. We return a sized part number, stock status and lead time — no price guessing, no minimum-order surprises.