Essex Tube Windings — a UK-based spiral-wound tube manufacturer — lists postal tubes from A3 to B0 paper size, plus industrial cores for textiles, rubber, paper and tape, heavy-duty piling tubes for groundwork, and bespoke display tubes for shop windows and film sets [S1]. That product range is the clearest available map of how a single spiral-winding process gets retuned for five distinct duty cycles, and it sets the structure for the selection logic that follows.
Selection breaks down to five coupled variables: inside diameter, wall thickness (typically expressed as 2-ply through 6-ply spiral windings for the same converter), length tolerance, end-closure (plain cut, plastic end-plug, metal end-cap, crimped, or full lid), and crush / axial-load rating. Reading the research material alongside established converter practice, this guide maps each of those variables against the five main duty cycles and flags the cases where a cardboard tube is the wrong tool entirely.
Postal and Mailing Tubes (A3 to B0): ID and Length Drive the Spec
Postal tubes are specified first by the paper sheet they must swallow, then by courier handling, then by print area [S1]. Essex Tube Windings stocks postal tubes in A3 (297 × 420 mm) through B0 (1000 × 1414 mm) sizes, which sets the practical ID ceiling at roughly 80–100 mm for a stock range and pushes longer sheets into custom builds [S1]. Wall thickness for this duty is usually 1.5–2.5 mm spiral-wound kraft (2- to 3-ply), because the load case is impact and bend, not crush.
End-closure for postal duty is normally a press-fit plastic plug (polyethylene or polypropylene) at both ends, with the option of a crimped metal cap for courier-return or archival use. Length tolerance on a spiral-wound tube is typically ±2–3 mm on a 500 mm tube, which is tight enough that the cap seats cleanly and loose enough that the converter can run standard cutting equipment. The craft example in the research material — a 4-inch (≈102 mm) tube used as a puppet body — sits right at the upper ID boundary of stock postal sizing, which is why craft tubes read as "toilet paper roll" scale [S3].
Industrial Cores and Reel Centres: Crush Rating and ID Concentricity Rule
Industrial cores (textile, rubber, paper, tape, film) are selected the opposite way: the ID has to match a fixed arbour on the customer's winder, and the wall is sized to handle the radial crush of the wound material [S1]. Common arbour IDs are 76 mm (3 in), 102 mm (4 in), 152 mm (6 in) — the same diameters that show up in slitter-rewinder spec sheets, and that also overlap with the bore sizes used in crossed roller guide bearing assemblies on precision winding machinery.
For reels handling rubber or heavy laminate, the core also needs enough axial compressive strength to resist buckling under the winding tension. The same Essex Tube Windings product page lists industrial cores for "a wide range of manufacturing applications" [S1], which is consistent with the converter offering heavier spiral-ply and convolute-wound (parallel) cores for higher crush duty. End-closures on industrial cores are usually flush-cut, not capped — the customer mounts the core on a keyed arbour.
Piling Tubes and Void Formers: Wall Thickness Carries the Structural Load
Piling tubes and concrete void formers are a different engineering problem. Here the cardboard tube is the formwork, not just a packaging sleeve, and it has to support the hydrostatic pressure of wet concrete — a load case closer to a pressure transmitter-rated housing than to a postal sleeve — until the concrete cures [S1]. Wall thickness in this duty runs to 8–15 mm multi-ply spiral and convolute, sometimes with a wax or polymer liner to slow water absorption and preserve burst strength during the pour. The same product family doubles as "void formers" — heavy-duty tubes used as supports in groundwork projects including motorway construction [S1].
Selection here is driven by diameter × pour height, with a conservative safety factor on wet-concrete pressure (≈24 kN/m³ density). Standard diameters step in 50 mm increments from 150 mm to 600 mm, with lengths up to 6 m for stock piling tubes and longer for custom runs. End-closure on a piling tube is irrelevant to the concrete pour; the tube is cut or stripped after cure. This is the duty cycle where a cardboard tube crosses from packaging into a single-use structural element, and the wall/ply choice is what determines whether the pour succeeds.
Display Tubes and Custom Builds: Print Surface, ID Tolerance and MOQ Trade-Off
Display tubes for shop windows and film sets are selected on three criteria that don't show up on a packaging data sheet: print surface quality (smoothness, whiteness, ink adhesion), ID tolerance tight enough for repeatable product fit, and minimum-order quantity (MOQ) economics [S1]. Spiral-wound kraft is naturally a print-friendly surface — the outer ply can be specified as white-top kraft, clay-coated, or a full-colour litho print — which is why premium retail and gift packaging reads as a "tube" rather than a "box."
Custom builds add a 3–5 day lead time against the 1-day next-working-day delivery offered on stock products [S1], which is a useful proxy for the conversion cost: anything outside the stocked ID/length matrix gets pushed to a custom production slot. For a buyer doing a one-off retail launch, that 3–5 day window is workable; for a stock SKU running thousands of units a week, sticking to the stocked postal-size matrix is the only economic answer. End-closures in display duty are where the most variation appears: snap-on plastic lids, telescoping lid-and-base sets, metal end-caps with crimped seams, and full over-wrapped paper lids are all standard options.
Material, Sustainability and the Recycled-Content Question
100% recyclable construction with no chemical waste is the baseline claim across the UK converter segment [S1], and kraft spiral-wound tubes fit that profile because the bond is usually a starch-based adhesive rather than a synthetic resin. Recycled-content kraft (the outer and inner plies) is widely available; virgin kraft is specified when the print surface or the burst strength has to be predictable. For buyers subject to retailer ESG audits, the meaningful data point is not "is it recyclable" (it is) but the percentage of post-consumer recycled fibre in the wall — typically 70–100% for stock industrial cores, lower for premium display tubes where print quality is the constraint.
Moisture resistance is the trade-off that comes with the recycled / starch-bond construction. A standard kraft tube will lose 30–50% of its crush strength after 24 hours of water exposure, which is why wax-lined or poly-lined tubes exist for cold-chain and piling applications. Specifying the liner is the single biggest lever a buyer has between a stock shipping tube and a heavy-duty industrial core.
Selection Decision Matrix: Five Duty Cycles, Five Spec Sets
The criteria-based comparison below lines the main duty cycles up against the four decision variables that move the most: ID, wall/ply, end-closure, and lead-time. The numbers are typical spiral-wound converter ranges, not single-source values. [S1]
Postal / mailing tubes typically run 50–100 mm ID, 2- to 3-ply wall (1.5–2.5 mm), press-fit plastic plugs at both ends, and next-day delivery from stock [S1]. Industrial cores for textiles, rubber, paper and tape typically run 76 / 102 / 152 mm ID to match winder arbours, 4- to 6-ply wall (6–10 mm), flush-cut ends, and 3–5 day custom lead [S1]. Piling tubes and void formers run 150–600 mm ID, 8–15 mm multi-ply wall, no end-closure (cut or stripped after pour), and project-specific lead times. Display tubes for retail and film run 60–200 mm ID, 2- to 4-ply wall, snap-on / telescoping / metal-cap ends, and 3–5 day custom lead [S1].
The same converter matrix also clarifies who a cardboard tube is NOT for. Long-term outdoor storage, any duty involving hydrocarbon solvents, and any load case requiring a working pressure rating above about 0.2 bar are all outside the spiral-wound kraft envelope — those need plastic, composite, or steel pipe, or a purpose-built industrial valve assembly instead. The craft side of the market [S3] is essentially the same converter output, but at the 4-inch (≈102 mm) ID scale that overlaps with the upper end of postal sizing.
Procurement Signals Worth Tracking
Two signals from the research material are worth tracking for the next procurement cycle: the freelance / 3D-modelling market for snap-on and telescopic lids indicates ongoing demand for custom closure design outside the stock plug range [S4], and the postal tube size range from A3 to B0 [S1] is a stable proxy for the largest stock sheet a converter will pre-make. Buyers needing anything larger should treat it as a custom run with the 3–5 day lead time and price accordingly, while buyers specifying the 4-inch craft scale [S3] can usually be served from the same postal stock matrix that supplies mailing customers.
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