General Method Of Cleaning Nickel Silver

PREFACE: The cleaning or stripping of metals may involve the use of abrasives, liquids or solvents which may splash or run off onto adjacent materials. Take special care to protect all adjacent materials, and do not use this procedure on metals other than those specified in the summary.
PART 1–GENERAL
1.01 SUMMARY

1. This procedure includes guidance on cleaning nickel silver building features to remove surface dirt and grease.
2. Nickel silver is a nickel alloy usually containing copper, nickel and zinc. Sometimes tin and lead are also added to improve the casting properties of the metal. Proportions vary depending on the type of nickel silver.
3. See 01100-07-S for general project guidelines to be reviewed along with this procedure. These guidelines cover the following sections:
   1. Safety Precautions
   2. Historic Structures Precautions
   3. Submittals
   4. Quality Assurance
   5. Delivery, Storage and Handling
   6. Project/Site Conditions
   7. Sequencing and Scheduling
   8. General Protection (Surface and Surrounding)
      These guidelines should be reviewed prior to performing this procedure and should be followed, when applicable, along with recommendations from the Regional Historic Preservation Officer (RHPO).
4. The cleaning approach should start with the most gentle means; clean water with a natural fiber brush; and if needed nonionic detergent; additionally an organic solvent may be needed.

1.02 SUBMITTALS

1. Samples: Clean a representative sample area using materials and methods specified at location specified by the Contracting Officer. The samples accepted by the Contracting Officer to serve as standard for the entire job. They will be marked and left undisturbed.

PART 2–PRODUCTS
2.01 MANUFACTURERS

1. Fisher Scientific Company
   Pittsburgh, PA
   http://www.fishersci.com/
2. Industrial Soap
   http://www.industrialsoap.com/
   722 S Vandeventer Ave,
   St. Louis, MO 63110
   314-241-6363
3. Axalta Coating Systems
   http://www.axaltacs.com/
   Glen Mills, PA 855-629-2582

2.01 MATERIALS
NOTE: Chemical products are sometimes sold under a common name. This usually means that the substance is not as pure as the same chemical sold under its chemical name. The grade of purity of common name substances, however, is usually adequate for stain removal work, and these products should be purchased when available, as they tend to be less expensive. Common names are indicated below by an asterisk (*).

1. Degreaser/standard solvent such as turpentine, phosphoric acid alcohols, mineral spirits or vinegar.
   1. Phosphoric Acid:
      1. A syrupy or deliquescent tribasic acid used especially in preparing phosphates (as for fertilizers), in rust-proofing metals, and as a flavoring in soft drinks.
      2. Other chemical or common names include Orthophosphoric acid.
      3. Potential Hazards: CAUSTIC TO FLESH; CORROSIVE TO CONCRETE, STEEL, WOOD OR GLASS.
      4. Available from chemical supply house or hardware store.
   2. Mineral Spirits:
      1. A petroleum distillate that is used especially as a paint or varnish thinner.
      2. Other chemical or common names include Benzine* (not Benzene); Naphtha*; Petroleum spirits*; Solvent naphtha*.
      3. Potential Hazards: TOXIC AND FLAMMABLE.
      4. Safety Precautions:
         1. AVOID REPEATED OR PROLONGED SKIN CONTACT.
         2. ALWAYS wear rubber gloves when handling
         3. mineral spirits.
         4. If any chemical is splashed onto the skin, wash immediately with soap and water.
      5. Available from construction specialties distributor, hardware store, paint store, or printer’s supply distributor.
   3. Vinegar (white or clear):
      1. Potential Hazards: CORROSIVE TO CONCRETE, STEEL, WOOD OR GLASS.
      2. Available from grocery store or supermarket.
      3. Vinegar itself, which contains about 4% acetic acid, may be suitable for some purposes requiring acetic acid.
         -OR-
         A mixture of 75% toluene, 24% acetone, and 1% butyl acetate.
         -OR-
         Use a solvent normally used for thinning nitrocellulose lacquers, such as DuPont Lacquer Solvent No. 3661-S (Axalta Coating Systems for use in mid-temperature 50-80 degrees F, or approved equal.
2. Non-ionic detergent such as “Environtex Zyfo Cleaner”, “Tergitol”, “Igepal CA-630”, or approved equal.
   1. “Zyfo” cleaner concentrate, a controlled suds, silicate buffered, non-ionic, rinseless-type synthetic detergent, containing no soap, free alkali, solvents, abrasives, acids, caustics or the like.
      -OR-
      Try the following cleaning solution:
   2. 7.5% thiourea solution (CS(NH2)2):
      1. A colorless crystalline bitter compound analogous to and resembling urea that is used especially as a photographic and organic chemical reagent.
      2. Available from photographic supply distributor (not camera shop).
   3. 1% concentrated sulfuric acid
   4. 0.5% detergent and wetting agent
   5. 91% water; potable, non-staining and free of materials detrimental to surfaces being cleaned
      CAUTION: AVOID AQUEOUS AMMONIA, AMMONIUM SALTS (SCC), HYDROGEN PEROXIDE (>10%) OR OXIDIZING ACIDS.
3. Corrosion Inhibitor/Cleaner: 1% Benzotriazole solution in warm water - 40 g. Benzotriazole per gallon of water (Fisher Scientific Company), or approved equal.
4. Clean, potable water
5. Distilled water
6. Clean, soft cloth
7. Plastic sheeting

PART 3–EXECUTION
3.01 PREPARATION

1. Protection: Protect all surfaces immediately adjacent to or below the area to be cleaned by covering with polyethylene sheeting.

3.02 ERECTION, INSTALLATION, APPLICATION

1. Using a clean, soft cloth, wipe the surface with degreaser, rubbing with the grain of the metal. Clean surface dirt and grease only, do not abrade the metal.
2. Wipe the surface with clean, soft cloth soaked with non- ionic detergent or cleaning solution (see Section 2.02 B. above), working a small area at a time.
3. Rinse the cleaned area with distilled water to remove traces of cleaner and corrosion products which can precipitate soon after cleaning.
4. Dry with a soft cloth.
5. After completion of cleaning, apply corrosion inhibitor/cleaner on a clean soft cloth and rub along the grain of the metal.