The vast majority of window cleaning is pretty basic; dirty glass is easily
cleaned using water, a glass cleaner, a scrubber (washer sleeve), and a
squeegee. Unfortunately (or fortunately depending upon your perspective),
mineral deposits, residue and other forms of pollutants are more stubborn,
and don’t simply wash away using this method. More serious tools are
commonly used to remove these tougher problems and make the Window Cleaner
look like a star.
Most people don’t realize that glass is not actually perfectly smooth; if it
was it would be easy to remove most forms of dirt. Glass surfaces are pitted
with microscopic indentations and this allows solids to bond to the surface.
Fortunately for you, a variety of chemicals (starting on page 53) can be
used to rid glass of even the most stubborn deposits. Here is a list of the
types of dirt and damage you will come up against, and some of the tools you
can use to restore the glass to almost new condition.
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Problem: Everyday Grime
Solution: Glass Cleaners
All windows are subject to climate conditions such as pollution, acid rain
and automobile exhaust. Inside, they can be abused by smoking, heating and
air conditioning fumes, and fingerprints. Perfect cleaning of a clear
surface (both sides) demands a solution that will reduce drag, and not
bleed, streak or dry out, and is strong enough to work for an extended
period of time. Dish soaps are not designed for cleaning glass, and often
leave a residue that gets dirtier faster. Go to Glass Cleaners.
Problem: Oxidation
Solution: Mild Chemicals & Abrasives
Oxidation, also known as etching, hazing or screen burn, occurs when metals
around windows (frames, screens, etc.) are exposed to rain or humidity and
deteriorate causing oxidation. This oxidation runs down the glass and
penetrates (or clings to) the glass. Mild acids, like Crystal Clear 550, or
abrasives like Sörbo Stain Remover (often combined with fine steel wool) are
often all that’s required to remove the oxidation. Go to Oxidation Removers.
Problem: Hardwater Stains
Solution: Chemicals and Abrasives
Hardwater stains occur when sprinkler water hits the building or rainwater
travels over concrete or a precast surface of a building and carries tiny
particles from that surface onto the window. After the rainwater dries the
mineral deposits are very hard to remove. Acid rain and sprinkler stains are
of the same nature due to the high concentration of minerals present in the
water. Much like Oxidation, mild chemicals and abrasives will take
care of most problems.
Problem: Overspray, Construction Leftovers
Solution: Scrapers and/or Chemicals
Most common on new structures, the process known as Construction Cleanup
involves removal of paint, stucco, tape, caulking, stickers and other
substances that end up on new glass. A razor scraper is generally the
answer, but many times chemicals make cleaning the window faster, and may
prevent scratching of the glass (see Scraping on page 13). Chemicals should
be used if mortar, concrete or stucco has been splashed on the windows. If
the glass has been burned by acids, chemicals are the only possible remedy
other than replacement. See Scrapers on page 33 - 35, and Oil-Flo on page
60. |
Problem: Scratches in Glass
Solution: Aggressive Abrasives, Sanding
Unfortunately scratches are common on glass; graffiti artists have found
glass panels on office buildings and shopping centers to be rich terrain.
There are no chemicals that can repair scratches, they can only be removed
by basically sanding or grinding the glass around the scratch down to a
level deeper than the deepest part of the scratch. There are two ways this
can be attempted; strong abrasives like compound polish used on cars, or
pads that are basically very fine sandpaper. Both techniques are applied
with electric drill motors that spin and grind the glass down. Rougher
grades are used first for deeper cutting, and finer grades are used to
deliver smoother glass. See page 39. There is specialty equipment designed
for larger jobs or businesses that make quick work of scratch removal. Go to Scratch Removal.
Problem: Glass Ages and Fogs
Solution: Protect After Cleaning
Like other parts of a building, glass ages from exposure to sun and other
pollutants. More importantly after chemical cleaning, the glass can be even
more susceptible to these conditions. Fortunately, glass can be protected
with liquids that are applied almost like car wax (you may be familiar with
Rain-X on car windshields). Building owners need to understand that the life
expectancy of their glass can be greatly extended if the glass is protected.
Go to Glass Protectants.
How to Succeed
Most experienced window cleaners have a wide variety of these chemicals and
cleaners with them at all times so they can experiment with the problem.
They also know to discuss the pros and cons of various solutions with the
owners. And most importantly, when testing the solutions, they work in
small, discreet areas in case the solution damages the glass or does not
remove the residue. |
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