What is silicone?
Silicon fluid is relatively short chain inorganic polymer called polydimethylsiloxane; please note the prefix poly before the units of dimethylsiloxane. The chain is not long enough to be typically called a polymer but by the technical definition, it is a polymer. Again we see here, the name "polymer" means less and less every time you see it.
The properties of silicon fluids range from very thin, volatile liquids that look and feel like petroleum solvents to thick heavy liquids that look like crystal clear honey. The only difference between the thin liquid and the honey liquid is the number of units in the dimethyl siloxane chain.
Automotive body manufacturing plants and paint shops avoid silicones, as they may cause ‘fish eyes’, small, circular craters in the paint finish
Polymers are used for different reasons they all have differing characteristics, i.e. as a paint sealant that contains four different polymers; two are used for durability, one to make the product easy to remove and one to give a great shine.
Silicon Polymer technology
a) Siloxane (R2SiO) or Polydimethylsiloxane (PDMS) The word siloxane is derived from the words silicon, oxygen, and alkane and is one of several types of silicon (polymerized siloxane, a resin as opposed to an oil) it’s a water-based amino-functional resin, although it contains silicon atoms, they are not made up exclusively of silicon, and have completely different physical characteristics from elemental silicon.
b) Silicon or Dimethylsiloxane (DMS) usually a petroleum distillate, (PD) solvent-based silicone, which after polymerization (cross-linking) will present an external hydrophobic surface. These penetrating-type, durable silicones oils form a flexible protective shield that prevents penetration of moisture and dirt.
c) Silicon (Ph2SiO) (Si14) – Silicones are polymers that include silicon together with carbon, hydrogen, oxygen, and sometimes other chemical elements. Some common forms include silicon oil, silicon grease, silicon rubber, and silicon resin
Silicon oils also referred to as dimethyl fluids are generally straight chain poly-dimethyl siloxane fluids ranging in viscosity from 0.65 to 100,000 centipoises. The typical ones used in wax or sealants formulations
However are between 350 to 10,000 centipoises viscosity. These have no reactivity and help with application or initial gloss. There are some modifications to improve characteristics of these oils by adding certain groups for instance aryl groups improve fire resistance and larger alkyl groups make silicon fluids body-shop safe. Some manufacturer’s use these modified silicon fluids only to claim that the product does not contain silicon oils.
Fisheye
[: Silicon Contamination; small circular, crater-like openings
that appear during or shortly after the spray application. or wax]
"Photo spotting" or fish eye is
caused by contamination of the surface to be sprayed. If the surface to be
painted receives the correct preparation it should not cause issues.
Cause
·
Spraying over surfaces contaminated with oil, wax, silicone,
grease, etc.
·
Use of thinner/reducer in place of a solvent cleaner.
·
Spraying over previously repaired areas containing "fisheye
eliminator" additive.
·
Once the surface ’fisheye, the paint should be polished or
cleaned with a chemical cleaner (PrepSol) as something has contaminated the
surface. There is no point in sanding down the surface and repainting as the
problem will not just go away.
Fisheye look like little
craters where the paint pulls away from the centre (looks like a fish eye and
hence the name)
Surface Preparation (For Polishing)
Why is it
important to remove Silicon?
It will have a negative
impact on the abrasive as it will tend to make the surface greasy as silicone
contains oils, which will affect the abrasives ability to remove defects
The properties that make
silicon so popular with car detailers, and some auto manufacturers, also make
it a very difficult product for the polisher to remove. During polishing, the
silicon mixes with the excess paint that is being removed from the surface to
form a smear.
[Can you
remove silicon from a clear coat completely? It is impossible to remove silicon from a
painted surface without using a chemical process so aggressive that it
dissolves the paint. Wax and grease removers will chemically remove one layer
of silicon off at a time but are unable to completely remove all the silicon.
Tests by Dr Michael Hauber at Menzerna using a spectroscope showed the layers
become thinner but the silicon remains. Removing silicon completely can take
place over time and involves a lengthy process of oxygen, chemicals, time and
sunlight.] Menzerna
Most types of silicone utilized in the auto
body and paint industries are water soluble additives used in waxes, polishes
and paint protectants. When fatty acids and polydimethylsiloxane derivatives
are generated, it creates silicone. Silicone also acts as a lubrication agent,
and when added to polish, wax and special coatings, it creates a smooth,
slippery finish.
Preparation- If
the car has been treated with silicon, use a wax and grease remover to remove
as much of the surface silicon as possible before polishing. You will not be
able to remove it all but it helps.
When a silicon-free polish works
on the surface of paint it uses aluminium oxide spheres, suspended in water and
hydrocarbons and a mechanical process to abrade the surface of the paint down
to the level of the bottom of the scratch. Silicon cannot be removed this way.
Silicon is removed by a chemical means and is designed to resist being removed
by mechanical means. Instead the silicon mixes with the blend of paint dust and
polish powder and it creates a smear on the paint.
We should differentiate between
swirl marks in the silicon layer and swirl marks in the paint underneath. Some
polishes may appear to remove the swirl marks in the paint but are really only
working on the layer of silicon. So the swirl marks in the paint itself remain
unaffected by the polishing and reappear after a few weeks, as the silicon is
being removed by time.
Removing Silicone - polishing is a mechanical process; silicon is a product
that has been designed not to be removed by mechanical abrasion. When using
Menzerna to polish surfaces which have been previously treated with silicon, a
smear may result. It is important to understand why this occurs.
There are lots of silicon
oils on the market. The high gloss properties that make silicon so popular with
car detailers, and some auto manufacturers, also make it a very difficult
product for the polisher to remove. During polishing, the silicon mixes with
oxidised paint and polish abrasive residue that is being removed from the
surface to form a smear. These products and or paint/ polish debris can be
removed with a wipe-down process or a specific silicon remover. You may not be
able to remove it all but it helps.
When a silicon-free polish
works on the surface of paint it uses aluminium oxide spheres, suspended in
water and hydrocarbons and a mechanical process to abrade the surface of the
paint down to the level of the bottom of the scratch. Silicon cannot be removed
this way. Silicon is removed by a chemical means and is designed to resist
being removed by mechanical means. Instead the silicon mixes with the blend of
paint dust and polish powder and it creates a smear on the paint.
We should differentiate
between swirl marks in the silicon layer and swirl marks in the paint
underneath. Some polishes may appear to remove the swirl marks in the paint but
are really only working on the layer of silicon. So the swirl marks in the
paint itself remain unaffected by the polishing and reappear after a few weeks,
as the silicon is being removed by time.
·
Hi-Temp's Prep Wash - to
prepare a paint surface for polishing, compounding, wax and / or polymer
sealant application (especially if changing from a wax to a polymer product)
this is a water-based paint cleaner designed to remove all traces of silicone,
oil, and buffing residue from any exterior paint surface
·
DuPont PrepSol II™ or Final-Klean
- spray onto a 100% cotton or a micro fibre towel and clean the
surface, DuPont now also sells the Sonatra Line, which are essentially wipes/towels, pre-moistened with
either Prep-Sol or Final-Klean, ideal for all high tech wiping applications,
excellent in use both wet and dry with high absorbent capacity
·
Dow Corning® OS-2 Silicon Cleaner and Surface Prep Solvent is
a volatile methyl siloxane (VMS) fluid that is compatible with a wide range of
materials. It will not harm most substrates, including plastics. OS-2 can be
used to remove silicone-based; greases, oils, car wax and car care products,
will soften cured silicones to facilitate removal
·
Hi-Temp's Prep Wash - to
prepare a paint surface for polishing, compounding, wax and / or polymer
sealant application (especially if changing from a wax to a polymer product)
this is a water-based paint cleaner designed to remove all traces of silicone,
oil, and buffing residue from any exterior paint surface
·
DuPont PrepSol II™ or Final-Klean
- spray onto a 100% cotton or a micro fibre towel and clean the
surface, DuPont now also sells the Sonatra Line, which are essentially wipes/towels, pre-moistened with
either Prep-Sol or Final-Klean, ideal for all high tech wiping applications,
excellent in use both wet and dry with high absorbent capacity
·
Dow Corning® OS-2 Silicon Cleaner and Surface Prep Solvent is
a volatile methyl siloxane (VMS) fluid that is compatible with a wide range of
materials. It will not harm most substrates, including plastics. OS-2 can be
used to remove silicone-based; greases, oils, car wax and car care products,
will soften cured silicones to facilitate removal
Current
Information
To
be of real practical use, a subject like automotive detailing requires a great
deal of research, and updating as new products become available. The advent of
materials like detailing clay, micro fibre technologies and finely milled micro
diminishing abrasives, suitable for ceramic nanotechnology paints are examples
of why it’s so important to monitor the industries new products, chemical
technologies and ideas that are constantly being introduced, as are the
techniques for applying them, hence all of the in-depth articles will be
up-dated and revised on a regular basis
Always
be willing to learn; because the more you learn, the more you’ll realize what
you don’t know. It is
said that knowledge is power, with the caveat that it includes access to a
reliable information sources. I would
like to think that these articles become an asset to anyone who is new to
detailing and to professional’s alike, as well as industry experts who seek to
advance their knowledge.
I
hope these articles are informative. They are based on the current status of
technical development as well as my experience with the products.
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 these articles as it helps other detailers further their knowledge.
As always if you have
questions, I’ll do my best to answer; bear in mind the only stupid questions is
the one that was unasked. Questions and/ or constructive comments are
always appreciated
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