Abstract: A variable capacitor is formed by metalized bands around the outside surface of a rigid ceramic tube spaced from each other at opposite ends of the ceramic tube to form capacitor electrodes. An elongated tube of Teflon.RTM. or other deformable resilient resinous material in tubular form is stretched to reduce its outer diameter from its normal diameter which is too large to accommodate the ceramic tube. The rigid dielectric tube is placed over the reduced-diameter liner. Tension is removed from the liner to afford relaxation of the liner, tending to return the liner to its original size and shape. Being confined by the ceramic tube, the liner is unable to do so, but securely engages the inside diameter of the ceramic tube. A threaded conductive piston, of a sufficient diameter to penetrate into and cause cold flow of the deformable liner material, is threaded into the liner, thereby removing air pockets and voids between the liner and ceramic.