Strip Brush Channel Materials: Galvanized, Stainless, Aluminium
Material guide · 7 min read · updated 2026-10-24
A strip brush is two materials: the filament that does the sealing or cleaning, and the channel (backing) that clamps the filament and mounts it. Buyers usually spend their effort on the filament, but the channel decides corrosion life, weight, how the strip handles heat and whether it can follow a curve.
This page compares the four common backing families — galvanized steel, stainless steel, aluminium and plastic — with real material data, and shows how to choose. For filament height and backing width rules, see our metal-channel strip brush selection guide.
1. How a channel strip brush is built
In a metal-channel strip, filament is folded over a core wire and crimped into a U-shaped metal channel, which then mounts directly or slides into a holder profile. Channels are sized by number (for example 3# to 10#); on our galvanized channel door bottom brush the channel width and height options run from 3 to 12 mm, lengths go up to 3 m, and overall height from 5 to 175 mm. The same product lists three channel base materials: SECC galvanized steel, SUS-304 stainless steel and 6063-T5 aluminium.
Plastic-base strips work differently: filament is fixed in a flexible extruded base, supplied on rolls, which can follow curves and irregular slots.
2. The four backing materials compared
Thermal expansion matters on long runs. Over a 3 m length and a 40 °C temperature swing, the coefficients in the table below mean a steel channel grows roughly 1.3–1.5 mm, a 304 stainless channel about 2.1 mm, aluminium about 2.8 mm and PVC somewhere between 6.5 and 13 mm. On long doors, ovens or outdoor gates, leave slotted holes or small gaps between strips, and avoid rigidly mixing aluminium holders with long steel channels without allowance for the difference.
| Backing | Thermal expansion | Corrosion | Best for |
|---|---|---|---|
| Galvanized steel | Steel 10.8–12.5 | Zinc layer protects; cut ends and scratches can rust in wet service | Dry or indoor machine guarding, door bottoms, cost-sensitive volume |
| Stainless 304 | 17.3 (316: 16.0) | Good in wet, washdown and outdoor use | Food plants, wet areas, outdoor doors, rotating seals |
| Aluminium 6063-T5 | 23 | Good; can be anodised | Light, non-magnetic holders and door profiles |
| PVC / PP plastic | PVC 54–110; PP 72–90 | Does not corrode | Flexible, curved or roll-supplied seals; light duty |
3. Galvanized steel
Galvanized steel is the default channel: stiff, strong, easy to crimp and cheap. The zinc coating is specified by mass; for example the common Z275 designation under EN 10346 means a minimum of 275 g/m² of zinc in total across both surfaces. Our catalogue lists SECC (electro-galvanized) steel for channel. Ask the factory which coating it uses if your strips will see humidity or outdoor exposure.
Galvanized channel is used in our metal-channel strip brush (3–10 mm backing, 5–180 mm filament height), in coil and disc formed brushes, and as the base of the horsehair door seal strip brush.
4. Stainless steel
Stainless channel — usually 304 type (18–20% chromium, 8–10.5% nickel) — is used where galvanized steel would corrode: washdown areas, food and beverage lines, outdoor gates and wet process equipment. Specify 316 (with 2–3% molybdenum) for salt or chloride exposure. Stainless frames are also used for formed brushes; our formed ring seal brush uses a stainless 4# frame with 0.1 mm stainless wire, so the whole seal is corrosion resistant.
5. Aluminium
Aluminium is used in two ways: as a channel material in its own right (6063-T5 on our product data) and, much more often, as an extruded holder profile — H, F, T or Y shapes — that a steel or aluminium channel strip slides into. 6063 is a medium-strength, heat-treatable extrusion alloy with good corrosion resistance and good response to anodising; under AS/NZS 1866 the T5 temper (sections under 12 mm) has a minimum tensile strength of 150 MPa and yield of 110 MPa, rising to 205/170 MPa in T6.
Examples: the H-type aluminium carrier door bottom brush and the garage door seal strip brush with 25 mm F carrier.
6. Plastic bases
Flexible PVC, PP or rubber-type bases let a brush bend around corners and be supplied on rolls, as with our flexible plastic-base strip brush (3–8 mm base, 10–40 mm pile) and the PVC-based rotary heat exchanger wheel seal brush. Their limits are heat and creep: as a reference point, pipe-grade PVC is rated to about 60 °C without pressure, so plastic bases are a poor choice near ovens, dryers or hot process equipment.
7. How to specify the channel
Browse strip brushes and brush seals and send your profile drawing via Request a Quote.
- Channel material: galvanized, 304, 316 stainless or aluminium; or plastic base type.
- Channel size (e.g. 4#, 5#, 7#) or backing width and height in mm.
- Holder profile if needed (H, F, T, Y) and its finish.
- Length per piece, straight or formed into rings, discs or coils.
- Environment: wet, outdoor, chemical, temperature range.
Frequently asked questions
- Which strip brush channel material is best for outdoor use?
- Stainless steel (304, or 316 near salt) or aluminium holders are the safest outdoors. Galvanized steel works but cut ends and scratches can rust over time in wet conditions.
- Is an aluminium strip brush holder strong enough?
- For door seals and guarding, yes. 6063-T5 aluminium extrusions have a minimum tensile strength of about 150 MPa under AS/NZS 1866 and are widely used for door and window profiles. For heavy impact, use a steel channel inside the holder.
- Can a strip brush be made to follow a curve?
- Yes. Use a flexible plastic-base strip for gentle curves, or have metal channel formed into rings, discs or coils for rotary applications.
- How hot can a plastic-base strip brush get?
- As a reference, pipe-grade PVC is rated to about 60 °C without pressure. For hotter areas, choose a galvanized or stainless channel with a heat-suited filament.
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