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UH BGM

Lesson 19 - Metal Cleaning and Polishing

Maintenance of metal surfaces embraces not only periodic cleaning but may include the protection of surfaces and occasionally the restoration of an original finish or color. Regularity is the essence of successful metal maintenance. Although the very low maintenance requirements and long life of metal have been prime reasons for their increased popularity, even metal must be cleaned sooner or later.


The frequency with which metal is cleaned depends on the following factors:
  1. Atmospheric conditions
  2. Geographic location
  3. Amount of traffic
  4. Level of appearance desired

Naturally, the metal surfaces near ground level are exposed to much more abuse, soil and grime than those on the 15th floor; likewise, a door handle or elevator panel will receive more use that a window mullion and frame in an office on the 39th floor.

Metal polishing and cleaning is a specialized operation that requires knowledge of the type metal being cleaned as well as the type cleaner being used. The four general classifications of metal surfaces we are usually concerned with are:
  1. Stainless steel
  2. Non-Ferrous
  3. Chromed, Anodized or Plated
  4. Ferrous

Each general classification will be reviewed in detail with regard to the following:
  1. General Information
  2. Care
  3. Precautions


STAINLESS STEEL

1. General Information
Most stainless steel is of the chromium nickel type which is very resistant to rust. IF rust streaks appear on the surface, look for the source in some iron or steel part nearby or possibly the cleaning equipment being used.

2. Care

Synthetic detergent and water may be used to quickly remove ordinary deposits of dirt and light greases. Whenever possible, the metal should be thoroughly rinsed and dried with a soft cloth after washing. In the case of tightly adhering deposits of grease, oil, soot, or dirt film from the atmosphere, the metal may be cleaned with pumice, finely bolted whiting, an oxide resistor, or stainless steel polishing powder. In all cases, rubbing should be in the direction of the finish lines.

There are many excellent prepared stainless steel cleaners on the market. The fact that many cleaners can be used is one of the outstanding advantages of stainless steel.

Stainless steel wool or stainless steel sponge may be used to remove abnormal accumulations of grease or dirt if care is taken not to scratch or mar the finish. It is important that the cleaning compound be completely removed with water after each cleaning.

3. Precautions

Never use iron-contaminated grits or polishing compounds on stainless steel. If iron becomes embedded in the surface, the stainless steel may show a brown discoloration, resulting from the rust of the iron particles. Do not use ammonia and water as a film will build up on the surface.

Ordinary steel wool or steel brushes should never be used on stainless steel. Always rub in the direction of the grain.


NON-FERROUS

1. General Information
Some uncommon examples are silver and gold. The more common non-ferrous metals are copper, brass, and aluminum. They have been used in the past and are still used today for interior and exterior building trim and ornamentation because:
a. it can be polished to a high luster,
b. it is relatively easy to clean and polish,
c. it is not affected by moisture or atmosphere and,
d. it has an extremely long useful life.

2. Care
Unless treated with epoxy, shellac or some other protective surface coating, they tend to tarnish and discolor rapidly. Cleaning and polishing should be scheduled with sufficient regularity to maintain the desired level of appearance. If the metal is protected with a surface coating, it should be:
a. washed with S.D. and warm water,
b. dried with a soft, clean cloth
c. polished with general purpose polish and Turkish toweling

Be extremely careful as the surface may be easily scratched.


If the metal is bare and is not protected with a surface coating:
a. use any well known or highly recommended brand of non-ferrous metal cleaner or polish. Follow the label directions closely
b. if necessary, rinse with clear water to remove excess build up
c. polish with a soft, dry cloth - preferably Turkish toweling

If the above methods are unsuccessful, use a light synthetic scratch pad or stainless steel wool pad with a petroleum distillate polish or other cleaner to remove heavy build up or tarnish. Although this may cause minor scratches, they will normally disappear with repeated polishing. Also an old toothbrush may be used for cleaning intricate patterns or other small areas.

3. Precautions
Do not use steel wool or steel brushes as they tend to scratch the surface and can leave iron particles embedded in the metal's surface.

With the exception of petroleum distillate preparations, cleaner deposits should be removed with clean water followed by a thorough drying. Petroleum based cleaners leave a thin protective coating which need not be removed after cleaning. If desired, coat a liquid wax on all metal surfaces after cleaning to facilitate later maintenance.


CHROMED, ANODIZED OR PLATED SURFACES

1. General Information
These are hard protective coatings that have been applied through a special process of electrolysis and are generally several thousandths of an inch thick. A wide variety of colors are available.

2. Care
a. Clean with S.D. and water
b. Dry with clean, soft cloth
c. Apply petroleum distillate if desired

3. Precautions
Do not use abrasives as they will scratch the surface. Do not use steel wool, brushes or coarse synthetic scratch pads.


FERROUS METALS

1. General Information
Common examples are steel, cast-iron and some alloys. They are used for decoration and trim but not extensively, since they lack the advantages of non-ferrous metals.

The exterior surfaces are generally protected with a surface coating such as paint, oil or some other preservative to discourage rust or oxidation.

2. Care
If protected by oil or preservative, wipe with an oil or preservative saturated rag.

If protected with paint or hard surface coating, wipe with light oil or petroleum distillate product.

Polish with a soft dry cloth.


3. Precautions
Avoid excess water. Re-apply paint or preservative as needed.


COMMON TYPES OF METAL CLEANERS AND POLISHES
1. Acid Base
Usually oxlitic acid, although stronger acids are used in some special duty metal cleaners. They clean by etching or actually removing a small amount of the metal surface due to a chemical reaction.

2. Alkaline Base
These are generally powder or crystal that we mix with water. They tend to be extremely strong and should be used with protective clothing and caution. Generally used on aluminum, they require neutralizing and a thorough rinse. A sealer may then be applied.

3. Abrasive Base
These chemicals clean by scratching away the soil and tarnish. They are generally composed of silicone or pumice. They tend to leave a film and will require thorough rinsing.

4. Polishing Cloths or Wadding
These are usually treated with solvent; the cloth or wadding has a polishing effect.

5. Petroleum Distillate Product or Wax
These products are similar to light oils. They are generally sprayed or wiped on. Any excess should be removed by polishing with a soft, clean cloth; however a film will remain to protect the surface.


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