Abrasives
Case Studies
The Marine Corps Air Station Naval Aviation Depot, Cherry Point, NC, is responsible for the complete
maintenance/rebuilding of naval aircraft. In 1990 the depot used 8000 gallons of CFC-113 and 15,600 gallons of
1,1,1-trichloroethane. By the end of 1992 CFC-113 usage had been reduced to 500 gallons annually and TCA
usage had been cut to about 4800 gallons annually. The replacements included: soap bubbles for leak checks;
aqueous power washers for electronics, motor, and engine shop use; terpene cleaners for hand wiping; steam
cleaning or wet sodium bicarbonate blasting for soil and carbon removal; and plastic media blasting for paint
removal.
Fennell, Mary Beth and Roberts, James Mark/Naval Aviation Depot, Hazardous Minimization-Saving Time,
Money , and the Environment, proceeding of the Aerospace Symposium, January 1993, Lake Buena Vista,
Florida, pp 39-46.
Dayton Rogers Manufacturing Company, Minneapolis, MN, is a short-run metal stamping company founded in
1929. Dayton Rogers had been using a vapor degreaser to remove oil-based lubricants from metal parts prior to
deburring. Currently, Dayton Rogers is using a vibratory tumbler with aqueous cleaning solution to clean and
deburr 75 percent of its manufactured parts simultaneously. The remainder of the deburring is done with a wet
sander which also cleans and deburrs simultaneously. Switching to a water-based lubricant facilitated cleaning. The
aqueous cleaning solution has a neutral pH and contains rust inhibitors for steel parts. All of the parts are air dried
after deburring. Dayton Rogers has eliminated the annual purchase of 1,100 gallons of 1,1,1-trichloroethane
(TCA). Capital cost was $9,000 for a wet sander and sheet-metal drier.
NET SAVINGS: $36,000 /YEAR IN OPERATING COSTS.
Minnesota Technical Assistance Program (MnTAP). Replacement of Vapor Degreasing Operation with
Deburring Process for Cleaning Metal Parts. Case Study, Minneapolis, MN.
A 3M electronics products plant was using ammonium persulfate, phosphoric acid, and sulfuric acid to clean
copper sheeting. This cleaning method generated 40,000 lb/yr of hazardous liquid waste. The plant switched to a
rotating brush cleaning system that scrubbed the copper sheeting with pumice. The abrasive cleaning method
generates a nonhazardous waste sludge that can be disposed of in a conventional landfill. The new cleaning system
cost $59,000. The initial cost was recovered in the third year of operation.
3M Company. Waste Stopper: Pumice on Copper. Environmental Engineering and Pollution Control Dept.,
Saint Paul, MN.
Gehl Company manufactures agricultural implements. Implements rejected by the quality control department are
sent back for remanufacture. The first step of the remanufacturing process is to completely strip the paint from
the implement. The old process of soaking the implement in a hot sodium hydroxide bath generated 19,000 lb of
hazardous waste annually, which cost $36,000 for disposal. The new stripping process is blasting with plastic
media. The media does not alter the finish of the metal. The blasting process uses 4,000 lb/yr of plastic media at
a cost of $8,000. The waste generated is a nonhazardous solid that is sent to a landfill. The plastic media blasting
unit cost $8,000. Net annual savings are $32,000 due largely to the elimination of hazard waste disposal costs.
Wisconsin Department of Natural Resources. 1992. Gehl Company; Using Plastic Media Blasting to Strip Paint
from Parts. PUB-SW-165 92, Hazardous Waste Minimization Program (SW/3), Madison, WI.
At the Smithville plant of ABB Power Transmission and Distribution Co. aqueous cleaning has replaced
chlorofluorocarbon (CFC) vapor degreasing. The distribution arrestors made here contain electrical contacts or
gaps that must be clean and tarnish-free. Various parts are stamped from aluminum, brass, and stainless steel using
water-soluble lubricants. A rotary tumbler containing the aqueous solution is used to clean the parts. After rinsing,
the parts are simultaneously polished and dried in a vibratory finisher containing cob meal media. The media is
heated to speed drying. The new process improves worker safety, eliminates CFCs, and costs less.
Solid and Hazardous Waste Education Center. Alternatives to Solvents: Degreasing for the '90s. University of
Wisconsin-Extension, Madison, WI.
Fleet Industries in Fort Erie, Ontario is using wheat starch blasting to remove excess bonding adhesive from clad
aluminum parts. Previous methods included manual hand grinding and chemical scraping
Oestreich, John and Todd Porter/Ogilvie Mills, Inc., Starch Media Blasting for Aerospace Finishing Applications,
METAL FINISHING, March 1993, p. 18.
Beech Aircraft in Wichita, Kansas, a division of Raytheon Corp., replaced methylene chloride stripping of
defectively painted aircraft parts with wheat starch blasting in July 1991. The parts cleaned include thin
aluminum clad and magnesium elevator skins, and new magnesium castings. The starch remaining on the skins is
removed by a warm water rinse. The more porous castings must be scrubbed to remove the starch. No surface
damage or panel deformation has been observed due to the blast cleaning process. Alodine chemical films are left
intact.
Oestreich, John and Todd Porter/Ogilvie Mills, Inc., Starch Media Blasting for Aerospace Finishing Applications,
METAL FINISHING, March 1993, p. 18.
Lockheed Aircraft Services in Ontario, California is a maintenance facility for military aircraft. They are using
wheat starch media blasting to remove polyurethane topcoat and epoxy primer from aluminum and fiberglass
substrates. Selective stripping allows them to remove layers of paint down to primer or substrate. Lockheed has
found starch blasting to be particularly effective on radar absorbing materials. The anodized finish on metal
substrates can be left intact.
Oestreich, John and Todd Porter/Ogilvie Mills, Inc., Starch Media Blasting for Aerospace Finishing Applications,
METAL FINISHING, March 1993, p. 17.
Canadian Airlines International uses wheat starch blasting to remove Tedlar film and adhesive backing from
interior wall panels on Boeing 727's and 737's. The wall panels are made of thin aluminum and are completely
stripped and ready for refinishing in 30-35 minutes per panel. Canadian Airlines had previously used methylene
chloride strippers, vapor degreasing, non-toxic chemical strippers, and heat with handscraping to remove the film
and backing. The starch blasting process is not labor intensive and results in a excellent surface finish.
Oestreich, John and Todd Porter/Ogilvie Mills, Inc., Starch Media Blasting for Aerospace Finishing Applications,
METAL FINISHING, March 1993, pp. 16-17.
Canadian Helicopter in Edmondton, Canada is a commercial helicopter fleet. Starch media blasting is used on
aluminum, steel, magnesium, and fiberglass parts to remove polyurethane enamels and primers. Canadian
Helicopter reports removing 8 to 9 layers of paint with no surface damage to the substrate.
Oestreich, John and Todd Porter/Ogilvie Mills, Inc., Starch Media Blasting for Aerospace Finishing Applications,
METAL FINISHING, March 1993, pp. 16.
The General Dynamics Pomona Division installed a plastic bead-blast paint stripper in June 1988 to replace
methylene chloride stripping. Paint stripping is done on parts hooks from the painting operation and parts with
defective coatings. The bead-blast paint stripper occupies 9 square feet of floor space and uses plastic beads with
20 to 30 mesh size. The installed cost of the new system was $18,000. The waste generated from the methylene
chloride stripper was sent offsite for incineration at a cost of $10,000 annually. General Dynamics Pomona
Division also sends the bead-blast waste offsite for incineration, but at a cost of $5,000 annually.
Lisa M. Brown/USEPA and Robert Ludwig/CA Dept. of Toxic Substances Control, Evaluation of Five Waste
Minimization Technologies at the General Dynamics Pomona Division Plant, USEPA, Risk Reduction
Engineering Laboratory, Cincinnati, OH, 45268. EPA/600/S2-91/067 Feb. 92. page 3.
The Fox Valley Steel and Wire company, USA, is using sawdust to clean the nails it manufactures, instead of ozone-depleting trichloroethane. Since the US EPA began to encourage users to find replacements for trichloroethane, in the 1980s, most companies involved in the wire industry have switched to caustic hot water as cleaning agent. Fox Valley Steel, however, does not have a wastewater treatment plant, making caustic hot water prohibitively expensive. The company therefore decided to use sawdust to clean the nails, a process abandoned in the 1940s because it was too labour intensive. Accratec Engineering Inc. created a computer-operated sawdust tumbler for Fox Valley Steel, able to clean two tonnes of nails at a time. The sawdust used is waste from another company, Ort Lumber Inc., USA.
Sawdust replacing trichloroethane, OzonAction Newsletter, Number 35: Page 4, July 2000.
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