In many plants around the country, producers are becoming attracted to magnet positioners. These devices are replacing traditional bolt-down systems to adjust end rails on steel-lined prestress casting beds.
Introduced in the United States about five years ago, magnets have enabled producers to be more productive and more quality-conscious. Gone are quality problems associated with welding stops, as well as the yards of construction waste generated by plywood cutouts.
Bill Huber, wetcast production manager, for Mid-States Concrete Products Co. in South Beloit, Ill., says his production team welcomes the increasing technology of these simple but effective tools. In a recent budget meeting, Huber found himself explaining to the accountant why he has been buying more magnets each year. “It was a subtle shock when we had 200 magnets in our inventory,” says Huber.
It was easy for Huber to explain how magnets have allowed crews in the producer's wetcast operation to stay on schedule. The former draftsman just pulled out a production drawing of a recent panel the crew cast for a building at a local college. The project architect had designed a LEED-certified structure. Several windows would be an energy-saving feature. So he called out numerous windows in each panel. “Magnet-supported block-outs saved not only layout time, but helped us cast a better quality panel,” says Huber.
As producers like Mid-States use more magnets, they've also discovered some minor drawbacks. “Some of the early models presented our crews safety problems,” says Huber. “Once the magnets were set on the steel deck, workers found them difficult to remove.”
These versions relied on pry bars that, with a downward push, break the contact. The strong attraction needed to withstand the lateral forces of the fresh concrete they contain also means they were hard to handle.
Kevin Wald, Mid-State's operations manager, then had an opportunity to try a magnet with an on/off switch. “Our crews found these new magnets to be both safer and more productive than conventional magnets,” says Wald. These magnets can set quickly, without causing a fast pinch point. They also can be repositioned quickly.
Introduced earlier this year to the United States by Hamilton Form Co., Saf-T-Mag's on/off feature has attracted the attention of production managers. The key to the magnet's safety is that it won't attract steel until the worker activates it. With no magnetic attraction, the magnet doesn't accidentally slam into a form or pick up metal shavings and steel debris.
Once in place, workers simply use a wrench and turn the knob 90 degrees to activate the magnet's pull. To remove or reposition it, workers wrench the knob to the off position, disengaging the magnetic force.
The manufacturer offers the on/off magnet in two sizes. The 6-inch model has an adhesive force of 1000 lbs., and the 4-inch model has adhesive force of 500 lbs. Saf-T-Mag costs about 20% more than traditional models, according to the manufacturer.
Visit www.hamiltonform.com, or telephone 817-590-2111.