When should I use tube instead of rod?

Use tube for hollow real-world items like pipes, gun barrels, smoke stacks, and structural tubing. Rod is for solid elements like handrails, aerials, and structural bars. Tubes are also useful for telescoping assemblies where one tube fits inside another.

Can I telescope different size tubes?

Yes. Evergreen and Plastruct styrene tubes are designed to telescope — each size fits snugly inside the next size up. This is excellent for gun barrels, telescoping masts, and sliding parts. Brass tubes also telescope well.

What wall thickness do styrene tubes have?

Evergreen round styrene tubes have a wall thickness of about 0.69mm (0.027 inch) across the catalogue — for example a 7.1mm (.281") OD tube has roughly a 5.7mm bore. K&S brass tube runs thinner at about 0.36mm (0.014"), and Albion Alloys metric brass and aluminium tube is around 0.45mm. Walls are usually thicker than true scale, but needed for strength. For the thinnest walls at larger scales, use brass or aluminium tube.

How do I cut tubes cleanly?

For styrene tube, use a sharp blade and roll the tube while cutting, or use a dedicated tube cutter. For metal tubes, use a razor saw with a mitre box. Sand the cut end on fine sandpaper placed on a flat surface, rotating the tube to keep it square.

ModelCalcs

Tube Size Calculator — Structural Elements at Scale

Find the correct tube diameter and wall thickness for structural elements at scale.

Real Outer Diameter (mm)

Full-size outer diameter of the real pipe or tube you are modelling.

Real Wall Thickness (mm)

Full-size wall thickness (one side). Scaled down only as a guide — model tube walls are usually over-scale for strength.

ScaleSelect model scale, or choose Custom… to enter any scale denominator

MaterialSelect the material type

How We Calculate This

Scales the real-world tube outer diameter and wall thickness down by the model ratio, then matches the scaled OD to the nearest stock tube from major suppliers (Evergreen styrene, Albion Alloys / K&S brass and aluminium). The approximate bore (ID) is the chosen tube's OD minus twice its real wall, so you can check a telescoping fit before buying.

Formula

Scale OD = Real outer diameter ÷ scale ratio
Scale wall = Real wall thickness ÷ scale ratio
Nearest OD = closest stock tube size to scale OD
Approx ID = Nearest OD − (2 × tube wall)

Stock walls used: Evergreen styrene ≈ 0.69mm (0.027"), K&S brass ≈ 0.36mm (0.014"), Albion Alloys aluminium ≈ 0.45mm. Override the styrene or brass wall in Advanced options; the aluminium wall is fixed at 0.45mm.

Frequently Asked Questions

Related Calculators

Sheet Thickness Calculator

Find the correct scale styrene or brass sheet thickness for walls, panels and skins.

Rod Size Calculator

Calculate the right rod diameter at scale for pipes, rails, handrails and aerials.

Template Calculator

Generate dimensions for templates — circles, arches, angles and compound curves.

Structure Calculator

Calculate framing, bracing and panel sizes for scratch-built structures.

Rivet Spacing Calculator

Calculate realistic rivet spacing and row patterns at your model scale.

Last updated: February 2026

All calculations are estimates. Always verify quantities before purchasing materials.