Don't Play Mad Scientist
Just remember that anytime
two chemicals with completely different formulas and / or functions are
combined, at best the effectiveness of each chemical is reduced, and/or the
chemicals may not be compatible
Don't haphazardly mix
chemicals; pay attention to the order in which chemicals are to be added to
each other and do not deviate from the instructions. Even chemicals that mix to
produce seemingly safe products should be handled carefully. For example,
hydrochloric acid and sodium hydroxide will give you salt water, but the
reaction could break your glassware or splash the reactants onto you if you
aren't careful. Some rules are NOT made to be broken. That is true of the rules
used for chemicals. They are established for your safety and those of other’s
pH measurement
The term pH is a measurement
of the relationship between hydrogen ions and hydroxyl ions. When you have more hydrogen ions than
hydroxyl ions, you have an acid.
Likewise, if you have more hydroxyl ions than hydrogen ions you have a
base (alkali).
The pH scale is a
measure of the acidity or basicity (Alkali) of a solution. It is approximates
but is not equal to p [H], the negative logarithm base 10) Base (Acid) 1-7,
Alkaline 7- 14; the pH of a solution is temperature-dependent.
Unfortunately
the pH scale is logarithmic; for every integer that the scale decreases the
material is 10 times more acidic. Those of us in earthquake country know all
too well the consequences of a change of from 6 to 7 on the logarithmic, Richter
scale. The difference in the pH scale is just as dramatic and therefore just as
misleading.
Base (Alkali)
Alkalis neutralize acids, and solutions of
alkalis are greasy to the touch. The strength of an alkali is measured by its
hydrogen-ion concentration, indicated by the pH value.
They may be divided into strong and weak
alkalis: a strong alkali (for example, potassium hydroxide, KOH) ionizes
completely when dissolved in water, whereas a weak alkali (for example,
ammonium hydroxide, NH4OH) exists in a partially ionized state in solution. All
alkalis have a pH above 7.0.
The hydroxides of metals are alkalis. Those of
sodium and potassium are corrosive; both were historically derived from the
ashes of plants.
The four main alkalis
are-
1.
Sodium hydroxide (caustic soda, NaOH)
2.
Potassium hydroxide (caustic
potash, KOH)
3.
Hydroxide calcium (slaked lime or limewater, Ca (OH) 2)
4.
Aqueous ammonia (NH3 (aq)).
Their
solutions all contain the hydroxide ion OH-, which gives them a characteristic
set of properties.
If
the affected paintwork is not neutralized any remaining acid residue will be
reactivated each time it comes into contact with moisture and heat. Water
contains 2- hydrogen and 1-oxygen atom and will acts as a catalyst and a
carrier system for acid. Oxygen is an oxidizer; ozone is an allotropic form of
oxygen (an oxidizer is any component that emits oxygen); many chemical
compounds react to slight heating and an oxidizing process.
Acids, Bases, and pH
Water
quality and pH are often mentioned in the same sentence. The pH is a very
important factor, because certain chemical processes can only take place when
water has a certain pH. For instance, chlorine reactions only take place when
the pH has a value of between 6.5 and 8.
pH
literally means the weight of hydrogen. pH is an indication for the number of
hydrogen ions. It consisted when we discovered that water consists of hydrogen
ions (H+) and hydroxide ions (OH-). pH is an indication for the acidity of a
substance. It is determined by the number of free hydrogen ions (H+) in a
substance. The common term for pH is alkalinity.
Acidity
is one of the most important properties of water. Water is a solvent for nearly
all ions. The pH serves as an indicator that compares some of the most
water-soluble ions. The outcome of a pH-measurement is determined by a
consideration between the number of H+ ions and the number of hydroxide (OH-)
ions. When the number of H+ ions equals the number of OH- ions, the water is
neutral. It will than have a pH of about 7.
The
pH of water can vary between 0 and 14. When the pH of a substance is above 7,
it is a basic substance. When the pH
of a substance is below 7, it is an acid
substance. The further the pH lies above or below 7, the more basic or acid
a solution is.
The
pH is a logarithmic factor; when a solution becomes ten times more acidic, the
pH will fall by one unit. When a solution becomes a hundred times more acidic
the pH will fall by two units.
Total alkalinity
Is
frequently referred to as AT, defined as the amount of acid required
to lower the pH of the sample to the point where all of the bicarbonate [HCO3-]
and carbonate [CO3--] could be converted to carbonic acid [H2CO3]. This is
called the carbonic acid equivalence point or the carbonic acid endpoint.
When
an acid substance ends up in water, it will give up a hydrogen ion to the
water. The water will than become acid. The number of hydrogen ions that the
water will receive determines the pH. When a basic substance enters the water
it will take up hydrogen ions. This will lower the pH of the water. When a
substance is strongly acidic it will give up more H+ ions to the water. Strong
bases will give up more OH-
There
are several ways to define acids and bases, but pH only refers to hydrogen ion
concentration and is only meaningful when applied to aqueous (water-based)
solutions. When water dissociates it yields a hydrogen ion and a hydroxide.
Pure
water is said to be neutral, with a pH close to 7.0 at 25 °C (77 °F). Solutions
with a pH less than 7 are said to be acidic and solutions with a pH greater
than 7 are said to be basic or alkaline.
The following is a generalized list of
examples of pH:
·
pH 0 battery acid
·
pH 1 hydrochloric acid
·
pH 2 lemon juice, vinegar
·
pH 3 grapefruit
·
pH 4 tomato juice
·
pH 5 black coffee
·
pH 6 urine/saliva – acidic ^
·
pH 7 fresh water, milk – Neutral
·
pH 8 sea water – basic substances (alkali) v
·
pH 9 baking soda
·
pH 10 Milk of Magnesia®
·
pH 11 ammonia
·
pH 12 soap
·
pH 13 bleach
·
pH 14 liquid drain cleaner
Reactivity
Add
moisture (dew, rain, car washing etc.) and heat to this equation (reactivity) all
of which equates to a highly concentrated solution, which causes a concave
indentation (etching or alkaline staining) to the paint surface. This must be neutralized to stop the ongoing reaction
process as moisture acts as a catalyst and a carrier system, which will
permeate the paint system matrix.
Neutralization of
acids and bases
Sodium
bicarbonate or sodium hydrogen carbonate is the chemical compound with the
formula NaHCO3Many laboratories keep a bottle of sodium bicarbonate powder
within easy reach, because sodium bicarbonate is amphoteric, reacting with
acids and bases. Furthermore, as it is relatively innocuous in most situations,
there is no harm in using excess sodium bicarbonate
Surface
preparation - wash and then clean the paint surface by using a chemical
paint cleaner (Klasse all in one (AIO) or ValuGuard "N" New Car Prep
Acid - ValuGuard Acid
Neutralizer (Step I) - diluted 1:8 with distilled water it neutralizes acids
deposited on the paint surface and in the micro-pores of the paint
Base (Alkalis)- ValuGuard
Alkaline Neutralizer (Step II) - deep-cleans painted surfaces to remove
alkaline deposits
Acid
/ Alkali Etching Removal –
First clean the paint surface and then
neutralize the acid or alkali
2.
Use a
machine polish (Optimum Polish, Optimum
Compound) and a cutting (LC White,
Orange or Yellow) foam pad (speed # 4- 5.0 or 1200 RPM) to level the surface
3.
For PPG
CeramiClear™ Clear Coat or other hard clear coats substitute Menzerna for
machine polish; i.e. PO 203 S - Power Finish
4.
Use the
least aggressive polish/foam pad first, if this doesn't remove the problem
step-up to a more aggressive polish / foam pad set-up. If none of
the above remove the etching use a wet-sanding process with 2000, 2500 and
then 3000 (or 4000) grit finishing paper
I would like to
think that these articles become an asset to anyone who is new to detailing and
to professionals alike, as well as industry experts who seek to advance their
knowledge.
I hope the
above article was informative. By having some understanding of the ‘What’ and
‘Why’ as well as the ‘How’ along with a little science to help you understand
how the chemicals we use react, you can achieve the results you desire.
I would appreciate it if you
would share this article as it helps other detailers further their knowledge.
Questions and/ or constructive comments are always appreciated.
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© 2002 - 2012 TOGWT® (Established 1980) all rights reserved
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