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White Salt Bloom Problems Eliminated With New Tru Temp® Black Oxide Process From Birchwood Casey Call 952.937.7931 For Free Brochure, or download it.

Minneapolis, Minnesota: Now it's possible to produce high quality black finishes without salt bloom, according to officials of Birchwood Casey, manufacturer of the the new TRU TEMP® Low Temperature Black Oxide process.

Salt bloom is that white powder often appearing in recessed areas and holes on hot oxide finished parts. It creates an appearance of part contamination, destroys the value of the finished part and upsets customers.

Salt bloom occurs because ordinary hot oxide bath is very viscous and difficult to rinse off. By remaining on the finished part, the hot oxide bath residue grows into fine particles of salt which adhere to holes and corners of the finished part. Besides being unsightly, salt bloom can impede part function as may be the case with black oxide finished hand tools.

In contrast, the new TRU TEMP black oxide patented process employs solutions that are much milder and cooler. They rinse freely leaving a residue-free finish without salt bloom. Unlike conventional hot oxide processes which operate at a boiling 290°F, the TRU TEMP bath operates at 190°F - well below the boiling and spattering temperature range. It produces a true black magnetite coating of minimal thickness and with excellent corrosion resistance.

"The TRU TEMP process provides numerous quality, safety and cost-saving advantages over conventional hot blackening methods," according to Mark Ruhland, Birchwood Casey vice president. "It has all of the quality appearance features and more but with far fewer operator and environmental hazards."

The finish is a satin black .000020" with high corrosion resistance (100 to 300 hours salt spray) and excellent abrasion resistance. The finish is ideal for dimensionally critical components such as tooling, gears, bearings, and gages, and meets military specification MIL-C-13924C, Class 1.

TRU TEMP utilizes no EPA regulated chemicals and has very low caustic content so it presents no drain pollution problems. Electric immersion heaters are used in the TRU TEMP process compared to gas burners with conventional hot oxide, so fire hazards due to open flames are greatly reduced.

The TRU TEMP process is fast, just 5-15 minutes compared to up to 45 minutes for traditional oxide methods. The TRU TEMP process steps are:

CLEAN and degrease the parts in SAFE SCRUB® ST biodegradable liquid cleaner, mixed at 20% by volume; 150° F; 5-8 minute soak time.
RINSE in clean, overflowing tap water; 15 seconds.
APPLY BASE COAT, utilizing OXYPRIME® Surface Conditioner, mixed at 10% by volume; Room temperature; 2-4 minute immersion.
RINSE in clean, overflowing tap water; 15 seconds.
BLACKEN in TRU TEMP solution, mixed at 33% by volume; 190-200°F; 5-10 minute immersion, or until uniformly black in color.
RINSE in clean, overflowing tap water; 15 seconds.
SEAL in a water-displacing rust preventive such as SHEATH® RB1 oil, for a slightly oily finish; or in BARRICADE™ rust preventive, for a soft, dry finish; or in CLEARLOK™ urethane/acrylic topcoat, for a clear, hard dry film.

The new TRU TEMP process can be used in existing tank lines or in a new system from Birchwood Casey. The company offers complete tank systems in 40 and 100 gallon tank lines, and larger custom processing lines. This new technology opens up a whole new in-house blackening option for manufacturers. It offers them better control over the quality, cost, and scheduling of their black finishing, while avoiding the severe hazards of conventional hot oxide processes.

For a FREE new brochure on the TRU TEMP process, call Toll Free 952.937.7931, download it, or write to Birchwood Casey, 7900 Fuller Road, Eden Prairie, Minnesota 55344-9702. Fax: 952.937.7979.