Re: how do they make catalytic convertors

Ariel,

You are correct, an automotive catalytic convertor does look like a beehive. The "body" of a convertor is a ceramic piece called a honeycomb monolith. A monolith ("one stone") starts life as a paste and is extruded by a high-pressure ram through a metal plate with slots cut in it. It is the same process that makes fancy pasta shapes. The monolith is dried and fired to form a hard (but brittle) honeycomb. This is often coated with some more ceramic powder and fired again. Finally, the "active ingredients", platinum and palladium (the gray stuff), are added to coat all of the surfaces of the honeycomb.

The honeycomb shape is used to increase the surface area of the catalyst available to the exhaust gases without impeding the gas flow too much (back pressure in the exhaust system will cause the engine to stall).

I hope that answers your question. It doesn't sound too complicated but there's a lot of technology that goes into designing and manufacturing honeycomb monoliths that do not crack and clog and operate with different engine configurations.

A Mad Chemist.