A better idea: the decline in quality of number two auto bundles spurred the thought process that led to today's auto shredders

Recycling Today, Jan, 2002 by Brian Taylor

For the past several years, ferrous shred has been taken for granted as a benchmark scrap grade, but ferrous scrap veterans are aware that the prominence and even existence of the grade is a relatively recent development.

In terms of industrial processes, the shredding of automobiles, washing machines and other large objects is a recent innovation.

NOT A BUNDLE OF JOY

As steel mills during and after World War II looked for scrap metal to make up part of their furnace charge, scrap metal dealers used baling machines to create number two auto bundles.

"In those days, to make a number two auto bundle, the standard practice all over the U.S. was for scrap yards to buy auto bodies from the wrecker yards--they had been stripped to some extent--and they would typically torch off heavy components like the frame and cut those up into pieces," says Dr. Richard Burlingame, a consulting metallurgist from Cleveland. "Those heavy pieces were called hard steel. Then the hulk that was left had few high-density sections, so it was easily baled. That was your number two bundle."

Burlingame, who worked for Cleveland-based scrap processor Luria Bros. Inc. from 1961 to 1986, says the auto bundles were a low grade of scrap, but that open hearth furnace operators would still consume the bundles if they could be diluted in a large melt. "Everything in that car got baled together--including plastics and glass," he remarks. "In the late 1950s, the total amount of nonmetallics and nonferrous metals was up to 15% in a typical body that had been stripped down. This compares to 25% to 30% today. It's hard to believe now that there was any market for these bundles, but there was much more iron and steel used in cars then, until more and more plastic and composites and nonferrous metals came into the picture. There was no mystery or conniving or dishonesty. Everyone knew what a number two auto bundle was. Steel mills bought them cheap and used them for decades."

But the low-grade chemistry of the bundles eventually came to the attention of steel mills. According to Burlingame, it was the refusal of an Armco steel mill in Houston to accept number two bundles that inspired the Proler family in Houston to invent the auto shredder.

PUTTING THE HAMMER DOWN

When an important local scrap consumer--the Armco steel mill in Houston--began shifting away from number two auto bundles in 1957, the four Proler brothers who ran Proler International in Houston began to consider their options.

"We had to find a way in which to remove the residuals that were in auto scrap--like copper, aluminum, lead and the upholstery. The auto shredder was our solution," says Herman (Hymie) Proler, former chairman and CEO of that company, which has since been disbanded.

The design consisting of a rotor with attached swinging hammers that is at the center of the auto shredder had been in widespread use in the mining industry. The Prolers had already introduced it to the scrap industry with an application making "precipitation scrap" out of tin cans for the copper production market.

"We figured if we could shred these materials, if we could build one big enough, why not try the process with pieces of a car," says Proler. Brothers Hymie, Sammy, Jackie and Israel (Izzy) Proler played different roles in laying the groundwork for the shredding revolution.

The brothers' attempts to recruit existing hammer mill manufacturers to help them build a machine were unsuccessful, so they became their own designers, engineers and fabricators, with Sammy and Hymie in particular working up design drawings.

While there was some trial and error involved in designing such things as the bearing housings, lubrication systems and dust control system, Hymie says the results were encouraging from the start. "It was amazing that the first time we built it, the shredder was better than we anticipated," he comments. "We dropped a whole car in there, and there she went."

Their earliest models--dubbed Prolerizers--did not lack for horsepower. "The original motors were taken from naval destroyer escort vessels and had 12-foot flywheels and 6,000 horsepower," recalls Hymie.

The Prolerizer became a trademarked name, and Sammy Proler received a patent for the shredding unit when coupled with the use of bottom grates to produce a sized grade of ferrous scrap.

While today's shredders produce scrap that is fed into elaborate down stream systems that conduct positive sorts for aluminum, copper and other nonferrous metals, the recovery of iron-bearing scrap was the focus of the first machines.

"Initially, we tried a lot of things," recalls Hymie, who notes they experimented with an oven to burn off the upholstery from shredded pieces. "We didn't know the magnets would do such a good job. Our first magnet was a belt magnet, but we went to drums because the scrap was wearing the heck out of the belt. The drum had to be strong enough to draw the ferrous scrap to the center without also drawing the residue."

The development of the Prolerizer was watched at a distance with intrigue--and in some cases skepticism--by competing scrap companies. "The rest of the scrap industry was stupefied by this," says Burlingame. "How could you put a car body in a machine and do anything but just stall the mill? They couldn't imagine enough rotor radius, horsepower and hammer speed to do this."