Copper Brazes the Ante Production of brazed copper-brass radiators beginsin bid to oust aluminum

The eyes of the copper industry are focused on Pittsburgh.

In a factory on the city's west side, the world's copper producers have come together in an attempt to reclaim a market they once owned: automotive radiators.

The heavy soldered copper-brass radiator gave way to aluminum in the 1970s when the auto industry pushed for lower weight to reduce fuel consumption. By the mid 1980s aluminum radiators claimed 30% weight savings over their old copper-brass predecessors.

Today, about 95% of the original radiators in U.S. cars and light trucks are made with aluminum cores, says the Copper Development Assn. But after several years of research, the copper industry has developed a copper-brass radiator to compete head-to-head with aluminum.

In fact, the copper industry is attempting to cleverly turn the tables on its arch competitor by employing the same

ovens used by the aluminum industry to braze its radiators.

Brazing is the process of joining two metals with a filler metal at high heat, around 1,100F (600C). But brazing an aluminum radiator is tricky because aluminum melts at around 1,180F (640C). As a result, the material must be heated slowly to prevent meltdown. With copper-brass, the melting point is around 1,650F (900C), so metals can be heated quickly, speeding production.

The International Copper Assn. calls the process CuproBraze, and earlier this year it put the technique into production at Universal Auto Radiator Mfg. Co. in Pittsburgh.

Road testing likely will take place by year's end, in a light-truck application, says Johan Scheel, ICA vice president.

Can CuproBraze slow the radiator industry's migration toward aluminum? "We wouldn't do this if we didn't think we could turn the tide. We think we can win back some lost ground," he says.

Mr. Scheel points out that copper-brass radiators can be made up to 15% smaller than comparable aluminum radiators. The process itself allows the use of thinner tube and fin materials, generates less scrap and is simple and clean, using no flux, he points out.

Overall, the cost of production is at least 10% lower than aluminum, yet the process offers a throughput rate 50% higher than aluminum.

Weight, however, is aluminum's big advantage. A brazed copper-brass radiator can weigh about the same as - or slightly more - than a comparable aluminum radiator, but not lighter.

With the decline of copper-brass original radiators, copper content on a typical vehicle dropped in the early 1990s but has hovered around 46 lbs. (101 kg) since 1996.