A wholesale tube order that arrives 4 mm out of round is not a quality complaint, it is a purchase order that did not specify ovality. Tube is the one acrylic product where the dimensions you leave out are the ones that decide whether the order is usable.
The five lines that belong on the PO
- Outside diameter with tolerance — ±0.5% is achievable on cast tube up to 200 mm, ±1% above it
- Wall thickness with tolerance — ±10% is normal, ±5% needs to be negotiated and usually costs
- Length and cut tolerance — ±1 mm on a saw cut, ±3 mm if the end will be machined later
- End finish — saw cut, machined square, or annealed and ready to bond
- Colour and transmission — clear, opal, or a matched tint, with a physical sample approved before the run
Length is a freight decision, not a manufacturing one
Cast tube is produced in fixed mould lengths, typically 2,000 mm, and cutting shorter is easy while cutting longer is a new mould. A 2,400 mm requirement therefore becomes a bespoke run with a setup charge. If the design allows 2,000 mm plus a coupler, the price drops by a third and the lead time by three weeks.
How tube is packed so it stays round
Tube is stacked in a hexagonal nesting pattern inside a wooden crate, with the outer row supported by a sling rather than resting on the crate wall. A crate packed in a square grid leaves the corner tubes carrying the load of the stack and they arrive oval. On diameters above 300 mm, each tube gets its own cradle.
The tolerance conversation worth having early
If the tube will be bonded into a plate, ovality matters more than wall tolerance because the bond gap varies with roundness. If the tube is a display column, wall tolerance matters more because the wall is visible at the cut end. Tell the supplier which one the application depends on, and the specification can be written around the cheaper of the two. For the strength side of tube selection, cutting and edge work covers the finishing steps, and sheet and tube dimension conventions give the reference table.
Cast versus extruded tube is the first decision, and it is not a price decision. Extruded tube holds a tighter diameter tolerance and machines well, but it carries higher internal stress and cannot be solvent-bonded into a pressure application. Cast tube costs more and bonds reliably; for anything holding water, it is the only one of the two that belongs in the specification.
Ordering mixed diameters in one crate is efficient but needs a packing drawing. Tubes of different diameters nest badly and the small ones migrate to the bottom under vibration, where they take the load. A packing drawing that names the position of each diameter turns a mixed order into one that arrives usable.
Payment terms shift with the first order. A new tube buyer is usually asked for a deposit against a bespoke mould, and an established buyer with a repeat diameter is not. If the design is likely to repeat, order the first run at the standard 2,000 mm length and build the mould cost into the second order rather than the first.
Email your tube schedule, including diameters, walls and lengths, to oversales@rpplexiglass.com and we will answer with a cut list and a packing plan.
Wholesale tube buyers typically ask three specification questions before ordering.
Frequently Asked Questions
Q: What diameter tolerance is normal for cast acrylic tube?
A: About ±0.5% of outside diameter up to 200 mm and ±1% above it. Ovality, not diameter, is the figure that usually causes a remake.
Q: Can acrylic tube be supplied longer than 2,000 mm?
A: Only as a bespoke mould run. Standard cast tube comes in fixed 2,000 mm lengths, so a 2,400 mm requirement adds setup cost and roughly three weeks.
Q: How should acrylic tube be packed for export?
A: Hexagonal nesting in a crate with the outer row on a sling. A square grid puts the stack load on the corner tubes and they arrive oval.