1.3 x 1.1 mm

A brass micro tube with an outside diameter of 1.3 millimeters

This thin-walled tube from Albion Alloys has an outside size of 1.3 and a bore of 1.1 millimeters, from which a wall of only one tenth follows. It is supplied as one piece 305 millimeters long, from which you take as much as the build happens to need.

The whole range is built as a telescopic set. The diameters rise in steps of two tenths of a millimeter and the bore of each piece matches the outside of the one two sizes lower, so the sizes fit into one another with no noticeable play. That is how extending antennas, stepped gun muzzles or the piston rods of landing gear dampers are made.

Brass takes handling that plastic would not survive. It stands up to having its edge sanded into a thin ring, it can be soldered with tin, bent over a suitable former, and it does not break if the model falls. Before paint is applied, though, the surface has to be degreased and a primer for metal used, as acrylic does not hold on a smooth shine.

In practice this diameter is used for fuel and hydraulic lines, handrails, the exhausts of small engines, the barrels of vehicle-mounted weapons or the axles of moving parts. It is parted with a fine-toothed saw while being turned, because pliers would squeeze the wall into an oval. The burr that results disappears once the tip of a knife is worked into the mouth.

Storage is undemanding; it only pays to protect the ends from being crushed. Brass does darken with time, but the film can be wiped off before the build with fine steel wool or a polishing eraser, and the surface is ready again to take both solder and a primer coat.