How to care for Dura Coat finishes.


  • 1. General
  • 2. Rust Spotting
  • 3. Cleaning
  • 4. Graffiti and Severe Stains
The factory applied finish used on residential siding and trim panels is very durable and will last many years longer than ordinary house paint. However, it may be desirable for cosmetic purposes to clean the finish occasionally or perhaps repaint to a different color.

Dirt pickup may cause discoloration of the finish when it had been exposed in dirt laden atmospheres for long periods of time. Additionally, slight chalking will ultimately cause some change in appearance in areas exposed to sunlight. A thorough cleaning will often restore the appearance of the product and render painting unnecessary. An occasional subsequent light cleaning will help maintain a good appearance.

Rust spotting can occur from improper techniques in cutting and drilling of prepainted steel panels during installation. Hot chips from drilling or self-tapping screws, or chips from metal saws or cutting discs may embed themselves in the paint finish. These chips can rust and form unsightly red spots in the coating, giving the visual impression that the substrate may be rusting. Shearing of panels to length is recommended, but whenever saws, drills or cutting discs are used, the adjacent painted areas should be protected with a plastic cover. It is imperative to brush off any chips which are struck to the painted surface. A stiff bristle nylon brush is recommended. Care must be taken not to step on any chips as this will embed them and make removal more difficult.
In some cases, simply washing the surface with plain water using hoses or pressure sprays will be adequate. For areas where dirt collection is heavier or more persistent, a solution of water and a detergent (1/3 cup of Tide per gallon of water, for example) may be used. For embossed or striated finishes, a stiff bristle nylon brush is helpful. To minimize streaking, always wash from the bottom to the top. A clear water rinse should follow immediately. Another good cleaning detergent is liquid Ivory in the same solution as above.

On new factory-built housing, dirt pickup or staining may occur from deposits washing off the roofing prior to installation of the gutters. Unpainted, galvanized steel roofs in particular may cause stubborn staining on new siding.

For initial cleaning of this type of dirt staining, normal procedures may be adequate. A 50% solution of Stain Go cleaner in water, applied with a stiff bristle brush, should remove these stains satisfactorily. This cleaning is always followed by a thorough rinsing with clean water.

Mildew may occur in areas of high humidity and mildew spores can grow in dirt deposits, even on factory-baked finishes. To remove mildew along with the dirt, the following solution is recommended.

  • 1/3 cup detergent (Tide, for example)
  • 2/3 cup sodium phosphate (Soilex, for example)
  • 1 quart 5% sodium hypochlorite solution (Clorox, for example)
  • 3 quarts water

   
Strong solvent and abrasive type cleaners should be avoided, as they can damage the finish. Chalking compounds, oil, grease, tars, etc., can be removed by mineral spirits applied only to those areas which are contaminated. Always follow the use of mineral spirits with detergent cleaning and clear water rinsing. Concrete splatter must be removed immediately in order to eliminate staining. The use of acid to remove concrete splatter should only be used as a last resort.

Graffiti presents a special problem because of the many possible agents used, generally aerosol paint. It is better to use less active solvents progressing to stronger solvents until the stain is removed. Use nothing stronger than necessary.

Typical Solvent Classes Mainly for Fluorocarbon Surfaces:


Many solvents are flammable and / or toxic and should be handled accordingly. Keep away from flames, sparks, electric motors, etc. Use adequate ventilation, protective clothing and goggles.

Class I

These solvents have no permanent affect on baked fluoropolymer surfaces.

  • Denatured alcohol (ethanol)
  • Isopropyl (rubbing alcohol)
  • VM&P Naphtha
  • Mineral Spirits
  • Kerosene
  • Turpentine

 

Class II

These solvents should be used with caution. Limit contact to 5 minutes and test before using.

  • Xylol (Xylene)
  • Toluol (Toluene)

 

Class III

These solvents should be used with caution. Limit contact to 1 minute maximum and test before using. Some solvents may even remove the surface.

  • Methyl ethyl ketone (MEK)
  • Methyl isobutyl ketone (MIBK)
  • Ethyl acetate
  • Butyl acetate
  • Lacquer thinner
  • Paint remover and acetone should generally not be used.

Chemical Solutions


Certain chemical solutions may be necessary to remove severe stains, mildew, mortar, etc.

  • Sodium hypochlorite solution (bleach)
  • Hydrochloric acid (muriatic acid)
  • Acetic acid (vinegar)

 

Hydrochloric or muriatic acid, diluted with ten volumes of water, may assist in removing rust stains. Limit contact to 5 minutes. Caution: Acid solutions are corrosive and toxic. Flush all surfaces with copious amounts of water after use.

For additional care instructions see “Voluntary Guide Specifications for Cleaning and Maintenance of Painted Aluminum Extrusions and Curtain Walls”.