Double Layer Silicone Air Ducting

-70°C to +310°C 2 Ply Fiberglass Steel Helix

FKD025-ASH

£15.68

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Silicone Hose UK

HolmeBank Business Park, Station Road
Unit 5
Mirfield WF14 8NA
Vereinigtes Königreich

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Opening hours

Monday	07:00 – 19:00
Tuesday	07:00 – 19:00
Wednesday	07:00 – 18:00
Thursday	07:00 – 18:00
Friday	07:00 – 17:00
Saturday	07:00 – 13:00
Sunday	Closed

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Double Layer Silicone Air Ducting is a high-temperature flexible hose designed for air transfer in automotive, motorsport, marine, and industrial applications. Manufactured from two layers of silicone-coated glass fibre with a steel wire helix reinforcement, the ducting offers outstanding heat resistance, flexibility, and durability. Its double-layer construction provides greater strength and insulation compared to single-layer alternatives, while the smooth inner surface ensures efficient airflow with minimal pressure loss. Lightweight yet robust, this ducting is ideal for hot air transfer, induction systems, and engine bay ventilation where reliability under extreme heat is essential.

Key Features:

Material: Double-layer silicone-coated glass fibre for superior heat resistance.
Reinforcement: Steel wire helix for flexibility and crush resistance.
Construction: Twin-ply wall with smooth inner bore for efficient airflow.
Operating Temperature: Continuous service from -70°C to +260°C, with peaks up to +280°C.
Flexibility: Highly flexible for routing in tight engine bays and confined areas.
Applications: Hot air ducting, induction systems, cooling ducts, and engine bay ventilation.

The double-layer silicone-coated construction ensures outstanding resistance to heat, ozone, and ageing, while the embedded steel wire helix provides flexibility without risk of collapse under suction or tight bends. Its smooth inner bore reduces turbulence and pressure loss, ensuring efficient airflow in high-performance applications. Strong yet lightweight, the ducting is easy to handle, cut, and install, making it suitable for both professional workshops and custom-builds.

Applications include automotive induction and cooling systems, brake cooling ducts, turbocharger air feeds, HVAC ducting, marine engine ventilation, and industrial hot air transfer. Double Layer Silicone Air Ducting is widely used in motorsport, custom fabrication, and engineering projects where high heat resistance, flexibility, and durability are required.

Specifications

Type: Air Ducting
Standard: Silicone / Glass Fibre
Wall Thickness: 2.5mm
Coil Length: 4m

Size Guide

Inside Diametermm	Outside Diametermm	Bending Radiusmm	Coil Weightkg
25	30	16	0.95
32	37	18	1.08
38	43	22	1.1
45	50	26	1.2
51	56	32	1.32
57	62	44	1.45
63	68	55	1.66
70	75	60	2
76	81	65	2.12
83	88	75	2.36
90	95	82	2.44
102	107	90	2.84
127	132	105	3.84
152	157	125	4.16
200	205	150	5.98

Measurements are nominal and may vary slightly.

How to measure ID

Measure the pipe, not the old hose

Heat and age make a used hose swell and go out of round. Take your reading across the metal outlet the hose slides onto — that measurement is your ID.

Use vernier calipers

Set the outer jaws across the widest point of the pipe. A tape measure round a curve reads low by a millimetre or two — enough to buy the wrong size.

Take three readings, keep the largest

Rotate 60° between each. If they disagree the pipe is oval; size to the biggest figure so the hose still seals.

Round to the nearest listed bore

Silicone stretches slightly. If you land between sizes, go down to the smaller bore for a tight seal — never up.

Order by ID, always. Every hose on this site is listed by internal diameter. OD is given for clearance only — it changes with wall thickness and ply count, so it is never the ordering size. On reducers, quote both ends, largest first.

Construction

Material

Double-layer silicone-coated glass fibre

Superior heat resistance

Construction

Twin-ply wall with smooth inner bore

Efficient airflow

Reinforcement

Steel wire helix

Flexibility and crush resistance · Continuous service from -70°C to +260°C, with peaks up to +280°C

Double Layer Silicone Air Ducting

-70°C to +310°C 2 Ply Fiberglass Steel Helix

Hot air. Handled.

Silicone-coated glass fibre on a steel helix, for air nothing else will take.

INTERNAL DIAMETERS

25mm to 200mm

RATED

−70°C to +260°C

MATERIAL

Silicone / Glass Fibre

SOLD BY

The metre

Frequently Asked Questions.

Answers to the questions we’re asked most about sizing, fitment and performance.

Still can't find your answer?

What is silicone air ducting used for?

Moving air where an ordinary duct would fail - hot air feeds and returns, brake and diff cooling, engine bay and cockpit ventilation, marine engine room ventilation and industrial hot air handling. It is built from silicone-coated glass fibre with a steel wire helix.

What temperature will it take?

-70C to +310C, which is the reason most people choose it over cheaper ducting. PVC ducting tops out around +65C and polyurethane around +90C, so if your application is anywhere near hot components this is the material you need.

What sizes and lengths do you supply?

Available in internal diameters from 25mm to 200mm, lengths from 1 Metre to 4 Metres, in black, red, blue and grey. Order by internal diameter to match the spigot or duct outlet it slides over - the flexible wall stretches slightly onto a close-fitting spigot, which makes for a neat joint.

What does the steel helix do?

It stops the duct collapsing under suction and stops it crushing if something rests against it, so it works on both the pressure and suction sides of a fan or blower. Without a helix, any flexible duct pulls shut the moment you apply negative pressure.

Is the double layer worth it over single ply?

For anything demanding, yes - more mechanical strength, better insulation of the air inside, and a longer life under vibration and heat cycling. Single ply is fine for gentle ventilation; if the duct is handled, routed tightly or run continuously hot, the double layer is the better buy.

How do I cut it and connect it?

Cut between the helix coils with a sharp knife, then cut the wire with snips and file or tape the cut end so it cannot work through the wall or catch your hand. Connect by sliding over a spigot and securing with a worm drive clip, or join two lengths with a duct connector. Do not over-tighten the clip - you only need to nip the wall down, not crush the helix.