This invention involves apparatus and methods for making fibers by passing a molten material like glass, polymer, etc. through orifices or tips in a fiberizing bushing and then cooling the molten material coming from the tips and newly formed fibers using cooling tubes. The cooling tubes are made from precious metals and various alloys comprising precious metals, nickel and one or more of titanium, chromium, molybdenum, etc. The one or more fins attached to the top surface of a hollow tube to make the cooling tubes contain spaced apart gaps, notches and/or slots extending from the top edge of the fin to prevent warping of the fins and to make the cooling tube more bendable, adjustable during the operation of making fibers from molten material.