Copper might stand as a viable contender to
aluminum in radiator applications, but it could be a hard sell
for auto radiator manufacturers, who say they are unlikely to
switch back to copper-brass models from aluminum despite the
strength and corrosion-resistance benefits offered by the
relatively new CuproBraze technology.
Radiator manufacturers like Dana Holding
Corp., Toledo, Ohio, ceased making copper-brass radiators in
1989, shifting its focus exclusively to aluminum. The change
was primarily sparked by aluminum's big weight-savings
advantage over copper-brass, which translates into better fuel
Despite the development of CuproBraze,
manufacturers don't see a shift coming anytime soon. "Even
though they're touting it as a new technology, most of the heat
exchanger people would say aluminum is now entrenched and brass
would have a hard time kicking it out," said Ted Zielinski,
technical director of the Thermal Products division of Dana's
Automotive Systems Group.
Aluminum is used throughout the engine, and
introducing a brass heat exchanger could cause some corrosion.
"We don't like to mix metals," Zielinski said. Heavy-duty
vehicle manufacturers also have shifted to aluminum, attracted
by the lower cost of the metal vs. copper.
Even in developing countries like China, the
issue of fuel efficiency likely will eventually drive the
Chinese toward aluminum. China also is increasing production of
aluminum, which would further favor aluminum heat
But those aren't the only two metals on the
table. Dana said it is exploring even lighter materials that
also are heat efficient, strong and corrosion resistant. So
far, the company has looked into magnesium and titanium, both
of which are lighter than aluminum although the significantly
higher cost of the two metals is prohibitive.
"Everywhere I look there's room to argue
which one (copper or aluminum) is actually superior vs. one
design or another," said James E. Burns, design engineer at
Piedmont, S.C.-based Griffin Thermal Products Inc. "But it's a
debate that will be going on probably for the rest of my life
and probably my children's."
Like Dana, Griffin began a shift to aluminum
in the late 1980s and ceased using copper in the early 1990s.
The company has no plans to shift back anytime soon, noting
that it's not cost-effective from a design and investment
Comparing a 20.3-millimeter flat oval
geometry brass-type tube in a one-row CuproBraze radiator to an
aluminum radiator construction with a 26-mm core thickness for
the same engine shows that the aluminum radiator is
approximately 40 percent lighter, Burns said.
Major manufacturers like Griffin that supply
powertrain cooling systems also have made large capital
equipment investments to produce and meet the needs of
customers, he said, noting that major design changes in
equipment and heat exchangers would be required to reverse
these investments-not to mention convincing customers like car
and truck manufacturers.
Griffin acknowledges that the tensile
strength of raw aluminum isn't as strong as that of raw copper
and that the CuproBraze technology shows promise in heat
exchangers for non-standard heavy machinery. However, Burns
points out that manufacturers also have been able to make
durable aluminum products for the same applications.
Another deterrent the industry faces in
switching back to copper is work under way to build hydrogen
fuel cell powered vehicles and hydrogen power battery shells
for vehicles, for which aluminum is a better candidate, he
Even Climex World SA de CV, a dedicated
CuproBraze radiator company in Escobedo in the Monterrey
metropolitan area of Mexico, acknowledges that the technology
isn't a feasible alternative for passenger car radiators. "For
those, aluminum is still the best option," Jorge Warnholtz,
Climex World's plant manager, said.
However, the red metal seems to have found a
niche market. The CuproBraze technology is ideally suited for
the mining, off-road, construction, agriculture, heavy-duty
truck and electric power industries. Climex is getting ready to
sell replacement parts for such after-market heavy-duty
vehicles, and CuproBraze products offer strong mechanical
resistance given that they're subjected to extremely high
temperatures as part of the brazing process, Warnholtz
Demand for conventional soft-soldered
copper-brass radiators is showing signs of growth in the
Caribbean, Mexican and North American after-markets. Proveedora
de Herramientas y Accesorios para Radiador SA de CV, parent
company of Climex, began exporting in 2004 and has witnessed
growing copper-brass demand during the past two years,
Warnholtz said. "The customers in the U.S. are seeing that the
copper-brass radiator behaves better than the aluminum
counterpart that the heavy-duty units were equipped with
originally. Many people still like the repairability, they like
the ruggedness and they like the copper-brass radiator better
than the aluminum. People are beginning to switch back."
The company declined to specify its sales
levels, although Warnholtz did say that the soft-soldered
copper-brass radiators made by Climex World's parent company
has grown 20 percent this year vs. 2007. He declined to
disclose the number of units sold.