method to remove
Fairlawn Tool & Die cut its costs with a new rust from internal part features, such as threads.
Rust and corrosion is always a potential problem when working with cold-rolled steel (CRS). Despite the best preventative efforts, manufacturers, such as Fairlawn Tool & Die Co. Inc. (www.fairlawntool.com) in Hampstead, Maryland, occasionally experience troublesome rusty parts.
For some time Fairlawn hand scrubbed with an abrasive and solvent-oil corrosion inhibitor. Although the rust was removed, the process was expensive because of the labor, lengthy time to clean small parts, incomplete removal in recessed shapes, such as threads, and latent film left on parts that would cause smoke during subsequent welding processes.
Fairlawn now successfully derusts CRS 1018-grade parts with Picoclean X-Rust concentrate from Pico Chemical Corp. (www.picochemical.com). The shop immerses parts in a 20-percent solution at temperatures from 140 degrees to 160 degrees F in a 30-gallon utility tank for no longer than an hour. There is no agitation or special racking used, and parts rest in the solution in such a way that exposes all surfaces to the derusting fluid. Afterwards, the shop rinses parts off in cold water and air-blows them dry.
X-Rust makes surfaces passive so that corrosion prevention is not needed immediately. Some parts go directly to welding, which is performed with good bonding, low porosity, and no fumes. After welding, or if parts need to be stored, the shop applies a corrosion inhibitor.
Marc Singer, production manager at Fairlawn, says his costs now are lower compared with the shop's old method, primarily because less labor is involved and turnaround times are shorter. He says the solution changes color from yellow to green to blue before it needs to be rejuvenated or dumped, and a gallon of concentrate goes a long way.
"On some parts that have internal threads, we had great difficulty manually removing rust. But with X-Rust, they come completely clean," he says.