Profil trubka 8,3 mm

A tube with an outer diameter of 8.3 mm

The advantage of a hollow tube over a solid rod becomes obvious the moment a mouth is meant to be visible on the model. The end stays open, the depth is real and you have to drill or carve nothing. Eight point three millimeters of outer diameter corresponds to a fairly massive element - in larger scales it will stand in for a chimney, a collecting pipe or a silo, in smaller ones for a tank, say.

What to watch out for when cutting it

The wall of the tube deforms into an oval under the sideways pressure of a knife. So make a clean cut by turning the tube against the blade and gradually deepening the score all the way around, or use a fine saw. Then clean the mouth from the inside with a drill bit turned in your fingers, so that the burr disappears, and lightly break the outer edge.

The options for further modifications

A narrower profile can be slid into the cavity and so create a telescopic joint, a pin or a hinge. Holes for cross pieces drill easily, because the material is soft and does not tear out. Before painting, run a fine abrasive over the surface, so that the glossy wall takes the coat evenly.

The tube is sold in a bare white form, with no paint and with no surface finishing of any kind.

Combining diameters and end fittings

Interesting shapes come from joining several sizes. A narrower tube slid into a wider one creates the step that a telescopic piston or an exhaust extension has; a ring cut from a larger diameter will in turn serve as a flange at the end of a pipe. A thin strip fitted around the circumference will suggest a clamp or a collar.

Before painting, check that no shavings from drilling have stayed in the cavity - once sprayed they would cling to the wet coat and the mouths would turn into hairy tubes.