Coil Tubing. Coil tubing available in Bright Annealed Stainless Steel, OEM Tinned Bundy Steel and 3003-0 Aluminum in many diameters from 3/16”, 1/4”, 5/16”, 3/8”, 1/2” and 5/8”. Most are .028” or .035” wall thickness. For the Do it Yourselfer to make your own