Belt Skirting and Skirt Rubber Closing the Gap Between Chute and Belt
Belt skirting and skirt rubber for conveyor load zones. NR/SBR, EPDM, NBR and food grade, 6-12 mm thick, cut to your width and drilled to your clamp bar pitch.
Belt skirting is the flexible strip clamped under the skirtboard at a transfer point, closing the gap between the chute wall and the moving belt. Its job is to keep material inside the load zone: without it, fines escape at the belt edges, dust goes into the air, and what should be travelling down the conveyor ends up on the floor and in the structure.
Skirting looks like a commodity - a strip of rubber - and is usually bought that way, which is why it is one of the most common sources of housekeeping problems on a conveyor. The grade, the thickness and above all the gap it is set at decide whether it seals or whether it wears the belt edge. We cut and supply skirt rubber to your width, thickness and clamp bar pitch, in the grade that matches the material you are carrying.
What You Are Actually Getting
| Parameter | Specification |
|---|---|
| Function | Flexible seal between the skirtboard and the belt surface at the load zone |
| Standard grade | NR/SBR, general bulk material at ambient temperature |
| Heat grade | EPDM, for hot material and outdoor UV exposure |
| Oil grade | NBR, for oily material and hydrocarbon contact |
| Food grade | White NR or food-grade PU for grain, sugar, flour and feed |
| Abrasion grade | PU or high-abrasion NR blend for sharp lump and sinter |
| Thickness | 6 - 12 mm as standard, cut to your specification |
| Width | 50 - 200 mm, cut to the skirtboard height you have |
| Hardness | 55 - 65 Shore A for the standard NR/SBR grade |
| Supply form | Cut to width, drilled to your clamp bar pitch, in the lengths the chute needs |
| Fixing | Clamp bar, bolted or wedge-locked to the skirtboard |
Which Skirt Rubber Grade Fits Your Material
The compound is chosen by what the material does to it, not by price. Four grades cover almost every conveyor; the two at the bottom are for duty that eats the standard grades.
| Grade | Polymer | Hardness | Best for | Watch out for |
|---|---|---|---|---|
| NR/SBR | Natural / styrene-butadiene rubber | 55 - 65 Shore A | General bulk material: sand, gravel, coal, aggregate at ambient temperature | Swells in oil; hardens and cracks above roughly 70 C |
| EPDM | Ethylene propylene diene monomer | 55 - 65 Shore A | Hot material, clinker, sinter, coke; outdoor conveyors with strong UV | Poor resistance to oil and hydrocarbon - do not use where NBR is needed |
| NBR | Nitrile butadiene rubber | 55 - 70 Shore A | Oily material, recycled asphalt, oily scrap, oily fines | Costs more than NR/SBR and is not a heat grade |
| Food grade white | White NR or food-grade PU | 50 - 60 Shore A | Grain, sugar, flour, food and feed conveying | Cleanliness and inspection matter more than the compound itself |
| PU | Cast polyurethane | 70 - 85 Shore A | Sharp lump, glass, metal scrap, high abrasion duty | Less compliant - needs a straight clamp bar and a well-aligned belt line |
| High-abrasion NR | Premium natural rubber blend | 60 - 70 Shore A | Sinter, coke, iron ore fines, continuous high-tonnage duty | Still a wear part - monthly inspection, not annual |
The compound is half the decision. The other half is the gap it is set at, and that is a maintenance habit rather than a purchase.
How the Seal Is Set
Set the gap, not the pressure
Skirting works as a light contact seal, not a clamp. Pressed hard against the belt it wears both the rubber and the belt edge, and the belt edge is far more expensive than the strip.
Stagger the joints
A continuous run with butted joints leaks at every joint. Overlap in the direction of belt travel, or set the joints away from the main material stream.
Clamp bar pitch is the real dimension
We drill to your existing bar pitch so the strip drops onto the hardware already on the conveyor. This is usually the thing that decides whether a replacement fits or has to be re-drilled on site.
Leave room to take up wear
Skirting wears at the bottom edge. A strip cut to the minimum height has nothing left to take up, and the whole strip is scrap once the bottom 10 mm goes.
Match the grade to the material, not to the price list
An EPDM strip is not an upgrade on a coal conveyor - it is the wrong compound if there is oil present. The cheapest grade that survives the duty is the correct engineering answer.
Where Skirting Fails
- Wet and sticky material — Carry-back and build-up hold the skirt off the belt and the seal opens. The skirting is not the problem - the belt cleaner upstream is.
- Sharp lump at the load point — Sheet rubber cuts at the edge and then peels. A PU grade, or a shorter unsupported span under the chute, is the fix.
- High belt speed — Air pressure lifts a thin strip and material escapes underneath. A thicker section and a shorter free length hold it down.
- Heat at the transfer — Standard NR hardens and cracks. EPDM is the grade, and the clamp bar has to be checked for distortion at the same time.
Belt Skirting and Skirt Rubber FAQ
What thickness of skirt rubber do I need?
6 to 12 mm covers most load zones. A thinner strip conforms better to an uneven belt line; a thicker strip lasts longer where the lump is sharp. Send the belt width and the material and the thickness follows.
Can you cut to my width and drill to my clamp bar?
Yes. Skirting is cut to your width and thickness and drilled to your existing bar pitch, in the lengths the chute needs. Send the pitch and the height and it arrives ready to bolt on.
How is the skirting supplied?
Cut to your width and thickness, drilled to your clamp bar pitch, in lengths that suit the chute. Tell us the material you are carrying and we set the grade; the strip arrives ready to fit rather than to be cut again on site.
NR/SBR or EPDM?
EPDM if the material is hot or the conveyor sits outdoors in strong sun. NR/SBR for general bulk material at ambient temperature. Neither is right if there is oil in the material - that is NBR.
How often should it be checked?
Monthly for the first few months after fitting, then to your maintenance interval. What you are checking is the gap, not the strip: once the bottom edge lifts off the belt the seal has already failed, even if the rubber looks intact.
How Orders Run
T/T — 40% deposit with order, 60% balance before shipment. L/C at sight accepted for container orders.
Quoted per order. The schedule depends on the drawing, the quantity and the material — we state a firm date with the quotation instead of a catalogue figure.
15 months from B/L date against manufacturing defects. Claims supported by photos and batch number.
Packing, minimum order and Incoterms are set out in full on the quotation page.
Belt Skirting and Skirt Rubber Built to Your Drawing
Send the belt width, the duty and, if you have one, the drawing. We will specify it, quote within 24 hours, and ship samples in 2–3 days.
Talk to Our Engineers