Stainless Steel Care
Here is how you care and maintain your stainless steel products.
When using proprietary cleaners, it is essential that very low or zero chloride contents are present. Both Ajax “Spray & Wipe” and “Windex” claim suitability for use on stainless steel, but we do not have a guarantee of chloride level. 3M’s domestic “Scotch Brite Pads” seem very good for cleaning, provided they are used gently and not on polished stainless steel.
The cleaning procedure needs to be qualified as to whether it is being applied to:
Physical removal of deposits and their type, e.g. Fingerprints, atmospheric deposits, surface corrosion products, organic material or building materials.
Maintenance of an architectural finish.
The original surface finish of the stainless steel.
Cleaning
Stainless steel is often thought to be a maintenance-free material. Unlike gold and platinum, however, it is not a metal that never rusts and is not completely maintenance-free. Rather, it should be termed a building material whose beauty can be retained semi-permanently with proper cleaning and maintenance in addition to considerations as cited above, regarding design, fabrication, and installation.
Generally, special stainless steels with excellent corrosion resistance should be used for building entrance applications in seashore areas. A proper cleaning and maintenance routine, however, permits the use of common grades such as S304 & S316.
The cleaning frequency varies according to the geographical location, building element and structure; the general cleaning criteria are:
2 times/year for rural areas
3 times/year for other areas
A more frequent cleaning routine is advisable for more corrosive environments, however, such as seashore areas, laden heavily with wind-borne sea salt particles, areas near railroad tracks or iron works laden heavily with airborne iron particles, and volcanic areas. Even in less corrosive environments – eaves, soffits, under-eave components and other building components – on which pollutants readily accumulate, should be cleaned more frequently.
Routine Cleaning & Maintenance
Both exterior and interior building components require routine cleaning, the frequency of which is dependant upon environmental conditions and aesthetic requirements.
Well-designed facades will be effectively cleaned by rain reducing the amount of supplemental, routine cleaning to once or twice a year.
When severe environmental conditions are encountered or where design uses the rainless efficiently, more frequent washing may be necessary, and a guide is provided.
For heavier soiling, pressure jet cleaning with hot water to remove material, followed by rubbing with a suitable mild-abrasive cleaner, a water rinse and drying should do. Cleaners containing harsh abrasive should be avoided. If left on the surface chlorine compounds, in many cleaning compounds, may cause corrosion and cleaners with these substances should be avoided.
Special care must be taken with chemically coloured or painted stainless steel. Providing care is taken not to damage the surface, the method detailed as follows is suitable:
Rinse with water to remove loose dirt.
Wash with water containing soap, detergent or 5% ammonia, using a soft long fibre brush if necessary.
Rinse with water.
If required, remove water with overlapping strokes, working from top to bottom.
For heavier soiling, pressure jet cleaning will not be appropriate. Hosing with water and detergent, and if necessary, gentle rubbing with a soft cloth sprinkled with fine calcium carbonate powder could be tried, but this could take the gloss off the paint if done too vigorously or frequently and professional cleaning advice should be sought.
What Causes Stainless Steel to Rust?
A stainless steel may be discoloured by rust
If it is exposed to a more aggressive environment than that for which that grade of steel is intended, e.g. Highly polluted air, salt solutions or residues of cleaning agents containing chlorine;
If it has a rough surface finish that provides a foothold for corrosive substances and corrosion products from the surroundings;
If the design of the structure is inappropriate, with pockets and narrow gaps;
If the surface is contaminated by grinding swarf and other iron particles from tools used in the installation work;
If fasteners of ordinary steel are used for securing the material, or if the material comes into direct contact with adjacent components made of plain carbon steel in wet or humid conditions.
The risk of corrosion in the first three situations is highest for the lower-alloy stainless steel grades and can be reduced substantially right from the start by specifying molybdenum alloyed stainless grades (such as type 316). In the last two cases, the surface of the stainless steel will be discoloured by rust from the plain carbon steel.
