A corrugated web having tapered flutes is usable in straight-through flow
filter elements. The corrugated web can be made by passage between a pair
of corrugated rollers having tapered teeth. Methods of making usable
corrugated rollers include methods for generating the tapered teeth at
the end points and the extension between the end points. Corrugated webs
may be made from a variety of media, including certain media that
stretches in the machine direction. Methods of forming the corrugated web
into filter elements (e.g., air filter elements) includes forming filter
media by securing a flat sheet to the corrugated web. The filter media
may then be wound into a filter element, including application of sealant
during the winding process to close selected flutes.