Skill Level / Experience
This kind of work should
only be undertaken by a professional or hobbyist detailer; who is experienced
in colour-sanding (wet-sanding) / paint renovation, more so than detailing,
someone who uses a paint thickness gauge (PTG) to measure and document the
vehicles paint as this is a technique is capable of removing ~ 2.5 – 7.5 µ (microns) > 0.1 to 0.3 Mil
of clear coat
Results will vary depending
on your ability and the thickness of the factory finish. Wet-sanding
(colour-sanding) a complete vehicle body may be beyond the capabilities of the
average detailer or enthusiast; in this case we strongly encourage the reader
to consult a professional detailer. Correct wet-sanding takes a lot of
experience and practice to perfect. This statement is not meant to question
anything related to your detailing or paint re- finishing abilities just my
opinion on the risks involved
Some methods described may
be beyond the capabilities of the average detailer or enthusiast; in this case
we strongly encourage the reader to consult a professional detailer or body
shop concerning the matters discussed herein. The writer assumes no
responsibility, expressed or implied, due to misuse or misinterpretation of the
information or methods used, or for any vehicle damage or injury that may occur
due to the suggestions and information offered.
Focusing on one person’s
methodologies or the products or tools they use will seriously limit your
detailing experience and knowledge. Most importantly - choose carefully whose
advice you listen to, and more importantly what advice you act upon.
How to tell if the paint
needs sanding or compounding would be dependent upon what the vehicle is used
for and you’re detailing goals for it. The use of a paint thickness gauge (PTG)
is considered mandatory when wet-sanding
a)
Factory paint on a daily driver
probably wouldn’t be a good candidate, OEM paint is very thin and constantly
removing scratches will compromise its ultra violet (UV) protection necessitating
a re-paint
b)
Concours d’élégance
vehicle preparation while it's important to try to remove as many of the
defects as possible you are still limited by the thickness of the clear coat or
colour paint of a single stage paint
system. Originality is an important consideration with this type of vehicle.
I would only wet-sand
freshly painted or custom paint cars and strongly advise against wet-sanding
OEM paint finishes, as the paint is usually very thin, or wet-sanding any paint without first using a
paint thickness gauge (PTG) to check the thickness of available clear coat;
consider < 110µ ( microns) the very minimum
Be
cognizant that wet-sanding removes paint, you're then going to have to compound and finish
polish, these procedure will also remove paint, so it's vitally important that
you are working on a custom paint job or you have sufficient paint thickness,
experience, skill and confidence to wet-sand a factory finish.
Wet-sanding is the most
efficient method of ‘levelling’ a paint surface. When you use finishing paper
and a sanding block, any uneven paint or ‘high spots’ will be levelled as the abrasives in the finishing
paper are focussed by the applied pressure and the flat shape of the sanding
block, which removes material far more evenly until the surface
becomes level
Using a baking plate, pad
and an abrasive polish you are applying pressure over the ‘soft’ baking plate
that will follow the contours or high spots
Practice on something
expendable; as it takes a lot of practice to do correctly; and there is a very
small margin of error, which results in an expensive e-paint
Before you wet-sand and
polish any OEM finish, you should know this will void the paint warranty if you
remove more than 0.3Mil (7.5
µ (micron) as this will negatively impact the paint
systems ultra violet (UV) protection.
The following are the
maximum allowable clear coat reductions the major USA car manufacturers will
allow before the paint warranty becomes void; latest (2014) technical
service bulletin TSB) state 0.3 Mil (7.5 µ) maximum clear coat removal
Block wet sanding (finishing
paper and a sanding block) is the most effective tool for paint defect removal;
because of its linear process you abrade the paint surface flat until the
defects are removed. Wet-sand with Trizact 1500 grit, which will level the
surface and then use 3000 grit to remove 1500 scratches the paint, will have a
semi-gloss before the final polish / buffing even starts.
Finishing paper (sandpaper)
In
its manufacture the crystals are electrically charged so that they will stand
up. They are locked into a hard resin and when you apply the paper to a surface
it will remove the substrate of the material you are sanding. The crystals cut
in a negative raking motion, leaving inconsistent scratch patterns. Finishing paper is the most common item from
a larger group of products known as "coated abrasives" i.e. Aluminium oxide. Finishing paper is available in a variety of abrasives or
grit numbers i.e. 1000, 1500, 2000, 2500, and 3000
Its
"grit" rating is a reference to the number of abrasive
particles per inch of paper. It eliminates the risk of deep sanding scratches
by providing a uniform grit size. This makes sense if you imagine how small the
grit particles on a 1000-grit finishing paper would need to be to fit into a 1-
inch square.
Grit finishing paper is
referred to by the size of its abrasives (i.e. 2000-grit paper) the grit you
use depends on to what degree you want to polish or refine a surface. 1500 grit finishing paper abrades the (freshly painted)
surface level and then the 3000 grit removes the 1500 scratches
Micro-Surface Finishing
Products, Micro-Mesh™ - (use Ultra-Flex Micro-Mesh™ Aluminium Oxide for
finishing aluminum). These non-abrasive abrasives are considered a cushioned
abrasive in fact. Conventional sandpaper or finishing paper is designed to be
aggressive so that it will dig deeply.
In its manufacture the
crystals are electrically charged so that they will stand up. They are locked
into a hard resin and when you apply the paper to a surface it will literally
tear in and remove the substrate of the material you are sanding. The crystals
cut in a negative raking motion, leaving inconsistent scratch patterns.
Micro-Mesh™ does the
opposite. The backing is long lasting cloth to which an ultra-flexible
cushioning layer is applied. This cushioning layer will determine how far
forward you can push crystals before they will penetrate the cushioning layer.
On top of this layer, we
have very resilient glue, not a hard resin, but completely flexible glue that
will hold the crystals while allowing it to move and rotate. The crystals can
turn in any direction without coming loose. When you start to apply pressure to
sand with Micro-Mesh™, the crystals will go into the cushioning layer while
beginning to cut a bit.
If you push harder, they will
go further into the cushioning layer, which serves as a safety valve. It
determines how much pressure you can exert in a down ward direction.
Instead of a deep scratch
that sandpaper makes, Micro-Mesh™ produce a refined scratch that is close to a
RMS of 1.0. the abrasives are made with large, very uniform crystals that
recede into the Ultra-Flex matrix as pressure is applied, allowing the crystal
tips to all line up so they are level with the part being polished. This
technology provides a more brilliant, consistent finish.
The cushioning layer also
allows the crystals to cut with a planeing motion that leaves an extremely
consistent scratch pattern and allows you to achieve extraordinary levels of
gloss. Where conventional abrasives will take surfaces down to 51-76µ,
Micro-Mesh™ will take it down to2.5µ or less
Damp sanding
Simply a variation of wet
sanding (colour-sanding) except that you use less water and sanding discs
designed for use with this process. The water on the surface suspends particles
of paint removed off the surface from the abrading action of your sanding disc,
because it utilizes less water for the process this equates to less clean-up of
the work area. I’ve always
preferred air tools for sanding as they generally have less torque than
electric tools, which affords better control.
3M™ Trizact
P1500 Foam Discs – (ultra-fine 1500 grit)
allows you to level more serious defects and then the 3000 grit removes
the 1500 scratch, leaving a semi-gloss finish , which may save the ultra-thin
coating found on PPG's DuPont's SupraShield™,
Optech™ and CeramiClear™ as
they use an ultra-thin layer of ceramic
clear coat over the regular clear coat.
These
ultra-fine papers allow you to level serious defects without removing too much
of this ultra-thin final coating. The 3M Trizact P5000 (grit) Foam Discs are
available in three sizes: 3, 5 and 6- inch.
Foam Interface Pad
Use of a foam interface pad
between the sanding disc and the backing plate is recommended. A foam interface
pad is made to improve your results during sanding, refinishing and spot repair
projects. The foam pad improves the sanding disc's ability to follow the curves
and contours of a vehicle.
The foam interface pad makes
machine sanding smoother for the technician and enables the sanding disc to
conform better to curved body panels. Using an interface pad also reduces the
aggressiveness of the sanding action and reduces the chance of creating coarser
scratches.
New Abrasive
Technology
These ultra-fine cut
finishing discs are made from a Silicon Carbide Mineral embedded in a cured
resin medium on a flexible film. The polyurethane foam backing is designed for
wet use. 3M Trizact 5000 Discs should only be used with water for both machine
and hand sanding.
Colour Sanding (Wet-sanding)
Years ago it was called
colour sanding because automotive paints were single-stage (primer and a colour
coat) and when the finish faded from ultra violet radiation (UV-B) exposure,
sanding off the oxidized paint thereby exposing the underlying paint would
bring back the paint surface colour.
Re-painted panels can be
wet-sanded after 48 hours (check P-Sheet), however a good rule of thumb for
most paint systems is to wait for about 72 hours (max 7-14 days) subject to
climatic conditions
Clear coat paint in
combination with the basecoat forms the automotive topcoat, which gives the
vehicle its appearance. One and two component clear coats (1K and 2K) are
applied over both solvent and water-based basecoats. Now most detailers refer
to it as wet-sanding as opposed to colour sanding
Then, as now, most sanding
was done wet so the terms colour sanding, wet sanding and as all these process
involves a sanding block, block sanding all became interchangeable whether you
were sanding to restore single stage (BC) colour or to level the surface of a
clear coat (BC_CC) paint system to remove surface imperfections.
Block wet- sanding (finishing paper and
a sanding block) is considered the most efficient form of paint correction, by
ensuring a consistent pressure over the entire surface contact area and using a
long stroke; this is the most effective tool for paint defect removal because
of its linear process you abrade the paint surface flat until the defects are
removed and a perfectly ‘flat’ levelled surface is obtained. This provides an
optimum surface light reflection / refraction (in simple terms the light
reflectance from a mirror)
I am never too keen to
colour sand factory paint, but any aftermarket paint is a great candidate. Don't
start with less than 1500 grit finishing paper unless you have lots of material
to work with or some serious imperfections.
Wet-sand with 1500-2000 grit
finishing paper and then use a 3000 grit foam pad and an orbital polisher to
level the paint surface, this will ensure a ‘perfectly’ smooth paint surface.
Block wet sanding (finishing
paper and a sanding block) is the most effective tool for paint defect removal
only because you can sand the paint surface flat until the defects are
removed. Non- diminishing abrasives and
a flat foam pad are similar in application.
Sanding a paint surface is a
very labour intensive way to eliminate orange peel or other paint surface
problems; this method can take an entire day to sand a vehicle properly. Sanding
can be done by hand using 1500, 2000 or 2500 grit finishing paper and sanding
with a palm sander can be done with Finishing Film or 3M™
Trizact.
Wet-sanding
isn't something to be afraid of, providing you use the correct products and
methodologies; but it is a process that is very aggressive and should be used
with common sense and sufficient caution. I usually recommend 3M™ Finishing
Film for the inexperienced paint renovator using a palm sanders
because it is less expensive and can be used dry so that you can see the
results of your effort while you're sanding so you can see exactly what you are
doing. Trizact is used wet and goes much further than the Finishing Film but
you need to wipe the surface and remove the slurry to check your progress.
Made out of high impact ABS
plastic and it’s constructed in an ergonomic shape for complete comfort when
sanding. The tough rubber pad that is firm for wet or dry use. Perfect for wet
sanding as it's made from stainless steel and plastic and it floats in a
bucket. It also has the best paper clamping system I've ever experienced and
it's flat.
·
High-impact ABS plastic, tough rubber pad that is firm for wet
or dry use.
·
Ergonomic shape for complete comfort when sanding.
·
Stainless steel lever action clips to grip & pull the
sandpaper tight.
·
Tapered edges allow you to get into corners
·
2-34"W x 7-3/4"
Paint Removed by Wet-Sanding
When removing deep scratches
wet-sanding will remove less paint than a rotary polisher and a diminishing
abrasive, however using a non-diminishing abrasive would remove more paint (there are many variables involved with
the above hypothesis-pressure, speed RPM, linear motion, and etc.)
Using a medium abrasive grit
finishing paper and backing block will remove approximately technique is
capable of removing ~ 2.5
– 5.0 µ (microns) > 0.1 to 0.2 Mil of clear
coat; but there are many variables such as the abrasive grade of the polish or
compound and speed and pressure used, the density (hardness) of the paint and etc.
that may affect the amount of paint removed
These numbers should be
checked with a paint thickness gauge (PTG) at some point the remaining clear
coat numbers, not the repair itself will tell you that you need to stop
sanding.
Clear coat breakthrough can
happen very quickly, so check periodically, knowing how much clear coat remains
is extremely important. There comes a point when you must judge wither removing
a scratch will compromise the clear coat and if so you’ll have to ‘live’ with
the imperfection.
A paint thickness reading of 100
µ (Microns) is reasonably safe for wet-sanding 80-90 µ, I wouldn't use
anything stronger than > 2000 grit, 70-80 µ > 2500 grit and under 70
µ I would recommend the use of a glaze.
The readings tend to vary from panel to panel and
are thinner towards the panel edges.
If you have reservations
about the amount of paint surface removed or the amount of paint coating
remaining the use of a paint thickness gauge (PTG) is arbitrary
These numbers are offered as a guide
only, as there are too many variables to provide any more than an
approximation.
Note: 1 µ (micron) is 1/1000th of a millimetre or 0.0393700787 Mil or 0.001 of an inch
·
200µ + can be expected on older cars that have been hand painted or a
re-painted vehicle
·
100 – 200µ 4 – 8 mil - normal paint thickness
·
80 – 100 µ - 3 – 4 mils, thin paint
·
80 µ < - less than 3 mil, very thin paint
Speed
Pad velocity at an identical RPM; V = RPM (Area) A - 6.5-inch = 20.423 sq.ins V=
24,507 inches per minute
(IPM) Pad velocity is also substantially increased with a larger diameter
pad,
Clear Coat Thickness
A micron (µ) is a metric
unit that equals one millionth of a meter, or 1/1000 of a millimetre. A micron
is much smaller than a Mil. There are 25.4 millimetres in an inch and a micron
is 1/1000 of a millimetre. Using the micron measurement gives you a much better
idea of paint thickness because it's so much smaller.
The clear coat provides
gloss plus physical protection from the elements, including ultraviolet (UV)
radiation, which is in the upper level of a cured clear coat, removing more than
12.5µ of clear coat will precipitate premature paint film failure.
There is ultra violet (UV)
protection all the way through the paint, but the majority of it migrates to
the top ~15-22µ of cross-linked clear coat along with the thinner solvents and
particles.
Therefore removing clear
coat ultra violet protection is not a linear process; by removing a small
percentage of the clear coat paint tends to remove a larger percentage of the
ultra violet (UV) inhibitors.
So once you remove too much
clear coat you'll have no paint UV protection other than what you apply with a
LSP (providing it contains UV protection
Modern
clear coat paint finishes are so good today that they lull people into thinking
that vehicle paint has protection and shine when in reality there is not really
much there, other than the clear coat that has a thickness of ~25.4 µ. As a point of reference a sheet of copy
paper is 89 µ. One (µ) micron is roughly 1/80th of the
thickness of a human hair
Most
car manufacturers will only allow ~ 25% of the clear-coat thickness to be
removed without voiding the paint warranty and long-term durability problems
becoming an issue. That means that if you started off with 50µ of clear coat, you would only
be able to remove < 12.5µ
without voiding the paint warranty and possibly having a re-paint.
Be
cognizant that wet-sanding can remove > 12.5µ very quickly. Two variables
need to be established; (1) How much clear coat is
available (2) how much clear coat can be removed
without compromising long-term durability
Paint thickness gauge
Taking constant paint
thickness measurements during the wet-sanding process will ensure against
removing too much paint. A PosiTest DFT Combo, measures
paint on any metal; including steel and aluminium, a popular choice given many
cars have both steel and aluminium. It automatically recognizes the material
and takes a measurement
Sanding Prep
Wash paint surface
thoroughly to remove any surface contamination, fill a spray bottle with paint
cleaner/ degreaser (DuPont PrepSol II™ to remove old wax and
soluble contaminates, spray onto a 100% cotton micro fibre towel (DF
Towels - DF Concours products) and clean the surface. If you don’t
wipe the surface before you sand you will not remove the contaminants, you will
force (sand) them into the paint surface
The secret to a Concours d’élégance
winning paint finish is colour-sanding (before wet-sanding paint show vehicle
owners often have an extra 2.5 Mil to 3.0 Mil of clear applied).
The paint sections / panels
that are difficult and involve risk are usually those that are close to the
edges of a panel (as this is where the paint is usually thinnest) or highly
contoured areas. Flat areas like the trunk, hood or roof involve minimal risk.
Orange peel
It is possible to wet-sand
orange peel, but if you try to eliminate it completely you risk severely
compromising the paint thickness.
Wet-sanding levels the paint
(and removes orange peel, harsh acidic or alkaline marks, etc.) it removes
approximately 0. 1 Mil (3µ Microns) of paint from the vehicle using 2000 -grit finishing
paper. A digital paint thickness gauge
will allow you to measure the film thickness of the paint system which includes
the e-coat, primer, base coat (colour) and clear
Be cognizant that orange
peel is found on both OEM and re-painted vehicles. Modern Isocyanate resins
(clear coat) finishes are so good today that they lull people into thinking
that vehicle paint has protection and shine when in reality there is not really
much there, the clear coat that has a thickness of ~25.4
µ (micron). As a point of reference a sheet of copy paper is 89 µ
The
clear coat provides gloss plus physical protection from the elements, including
ultraviolet (UV) radiation, which is in the upper level of a cured clear coat.
Most car manufacturers will only allow ~ 25% of the clear-coat thickness to be
removed without voiding the paint warranty and long-term durability problems
becoming an issue.
That
means that if you started off with 50µ of clear coat (this will vary by vehicle manufacturer) you
would only be able to remove <12µ
without voiding the paint warranty and possibly having a re-paint.
Removing
clear coat ultra violet protection is not a linear process; by removing a small
percentage of the clear coat paint tends to remove a larger percentage of the
ultra violet (UV) inhibitors.
Defect removal – these pads are also
very effective when used for defect removal without flattening out paint
provided they are used with a soft flexible baking plate. Using the same
principle behind wet sanding; it’s dependent upon the baking plate used i.e. a
stiff baking plate (block sanding) is used to level paint, whereas a soft
baking plate will remove defects
You should initially try
these on a test panel and get an idea of just how fast they remove paint. Using
little or no pressure (machine weight alone) start a low 600-700 RPM and then
progress to 1200 RPM, at this speed the kinetic heat produced by these
pads is high so it is wise to constantly
check paint surface temperature. The pad / backing plate combination is rigid an
so acts in a similar way to 'block sanding’, removing the high spots before the
valleys, maintain the pad flat and parallel to the surface; a spritz of
distilled water can be used to reduce the surface temperature, but beware of
product spatter
CarPro Orange Peel
Removal Pads - you can now remove or substantially
reduce orange peel in the top layer without sanding. While removing orange peel
and deep defects you are also polishing the paint rather than leaving sanding
marks, which reduces the steps needed afterwards.
These pads
have a very aggressive abrasive and are deceptive; they have twice the rate of cut of typical wool pads. They
don't dull the paint like sanding so it may appear you aren't removing paint
but you most certainly are.
They
are intended for use by professionals who are very familiar with paint film
thickness, using and interpreting the results of a paint thickness gauge (PTG)
compounding, polishing, and the dos and don’ts of paint correction. Theses pads
are designed for use with a rotary polisher (1000 RPM <) average removal is
approximately 5µ (0 .2Mil) - 7.5µ (0. 3 Mil)
These pads are available in
two configurations: Denim (2000 Grit) is the more aggressive and designed for
the removal of severe texture from refinished paints and Velvet (3000 Grit) is
used for removing light orange peel from thin, factory-applied paint; both
pads utilizing CarPro Fixer as a
lubrication / compound.
Use very little pressure and
check the paint surface temperature often. Similar to ‘block sanding’ the pad /
backing plate are rigid enough that when used correctly it abrades the paint
ridges (high spots) faster than the valleys. Either pad will polish the paint
as it removes orange peel requiring only one or two additional polishing steps
to create level paint that reflects accurately. These pads should only be used
with proper knowledge of clear coat thickness in conjunction with a paint
thickness gauge. As with any aggressive
abrasion method be very cautious with factory OEM paint.
There are two
considerations; (a) how
much clear coat (b) how
much ultra violet protection can be removed, they are not interchangeable. The
following are the maximum allowable clear coat reductions the major USA car
manufacturers will allow before the paint warranty becomes void; The following
are the maximum allowable clear coat reductions the major USA car manufacturers
will allow before the paint warranty becomes void; latest (2014) technical service
bulletin TSB) state 0.3 Mil (7.5 µ) maximum clear coat removal
Wet or Dry Sanding
Either is a safe option as
there is no risk of electric shock risk as you’re not mixing water / electrical
current. If possible, it is always better to use a lubricant. This will extend
the life of the finishing paper greatly and keep the material from loading. It
will also keep heat generation to a minimum.
There are many types of
lubricants, but generally water is best. It is best to work using a light mist
or spray. Flooding the work surface or work piece is not recommended as it will
cause the abrasive to aquaplane across
the surface, making less surface contact and removing less material
3M™ Trizact
P5000 Foam Discs – (ultra-fine 5000 grit) they allow you to level more serious defects ,
which may save the ultra-thin coating found on PPG's DuPont's SupraShield™,
Optech™ and CeramiClear™ as
they use an ultra-thin layer of ceramic
clear coat over the regular clear coat.
These
ultra-fine papers allow you to level serious defects without removing too much
of this ultra-thin final coating. The 3M Trizact P5000 (grit) Foam Discs are
available in three sizes: 3, 5 and 6- inch.
Foam Interface Pad
Use of a foam interface pad
between the sanding disc and the backing plate is recommended. A foam interface
pad is made to improve your results during sanding, refinishing and spot repair
projects. The foam pad improves the sanding disc's ability to follow the curves
and contours of a vehicle.
The foam interface pad makes
machine sanding smoother for the technician and enables the sanding disc to
conform better to curved body panels. Using an interface pad also reduces the
aggressiveness of the sanding action and reduces the chance of creating coarser
scratches.
The 3M
Random Orbital 6 Inch Air Sander is designed to leave a smooth finish
without over-sanding any particular spot. The abrasive disc and disc pad on
this dual action sander move in two distinct oval patterns. No single abrasive
particle follows the same path twice. Therefore, the results are smooth and
even across the entire sanded area, whether it's a small spot or an entire panel
.
3M Random Orbital 6 Inch Air Sander
The Air Sander has a 3/16-
inch orbit, which is rated for general purpose sanding. A Stikit™
Low Profile Disc Pad is included with the sander. Use 1500, 2000 and 3000 grit Trizact sandpaper used wet
to level the paint then a rotary polisher and a foam pad to produce a gloss
finish. Check out the selection of 3M sanding and finishing discs for
more disc options
Wipe down Process
Anhydrous Isopropyl alcohol [Molecular formula C3H8O] for all-purpose cleaning, isopropyl
alcohol, is a colourless liquid with a pleasant odour, and is highly flammable.
Isopropyl alcohol also known
as IPA, is excellent for removing oils / grease from paintwork before applying
your final sealant or wax after polishing, or used to clean stone chips before painting. Wiping
the finish with a micro fibre cloth you may feel that the swirls have been
removed, only to have them reappear when applying the final wax or sealant.
After polishing a section, mist and wipe to fully remove residues and reveal
the true paint finish.
a)
Polymer sealants will not form a proper monocular bond with a
paint surface if there are any silicone or synthetic oils present, they will
also affect durability if not removed
b) Silicone
will cause surface smearing and will affect abrasives effectiveness,
product bonding and durability (See also Silicone Removal)
A wipe down after polishing
or compounding is used to remove the carrier oils and wax used for surface
lubrication and allows you to inspect the surface to determine if the surface
is defect free or if further work is required. When polishing or compounding to
remove fine swirls or holograms, it's easy for residues and / or waxes or oils
to settle in the swirls, hiding the true paint finish (drop back). Be aware
that you may need to repeat this process more than once, perhaps 3-4 times may
be necessary.
The effectiveness of this process is dependent upon a few
factors; strength of product used, surface temp of paint, pressure applied and number
of passes will all affect the outcome.
The wipe down process should
be carried out both before to ensure
a surface that is free of any debris and after
to ensure that defects have been removed as opposed to masked by any
lubrication oils or fillers left behind after the polishing process. The
wipe-down process may need to be repeated to ensure a perfectly ‘clean’, debris
free surface
Application
methodology - Isopropyl alcohol (IPA) if used undiluted it flash dries
(evaporates) rapidly, which lessens surface inspection time and will also
redeposit the oils you're trying to remove. Alcohol and water will emulsify any
oils, enabling them to be removed
Fill a fine misting spray bottle with an 8:1
ratio of (IPA) / distilled water solution. Spray the surface you have just polished and allow
the solution sit for approximately 15 seconds. If it flashes too quickly (hot surface or
environment) use further dilution
Agitate
the area with a clean, soft
100% cotton micro fibre towel (you may need to repeat this process) change the towel to a fresh
quarter after each panel to ensure oil and debris are not re-deposited and observe. What you have done is remove any
silicone, wax, and oils that may have filled any remaining swirls.
Now using your
surface inspection light, shine the light directly on the panel and look for
fine swirls. If they are still present, you should be able to see them. If not
you will see a clear bright reflection from the panel with a great shine, and
clarity
Notes:
1.
For
‘hard’ clear coat use a very light dilution rate, for ‘soft’ clear coats use a
heavier dilution
2.
After
the paint surface has been subjected to a chemical cleaning its protective
layer (s) have been removed and the
paint surface left without protection, so it is very important that a wax or
polymer protection be applied
immediately.
Alternative
products
·
Menzerna
Top Inspection (PP95) – use to inspect your work, use this water-based cleaner
that removes dust left by compounding and any lubricating oils so you can see
the real results of your work. There are no silicones or fillers, just gentle
cleaning agents to uncover the real condition of your vehicle’s paint.
·
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™ - http://www.xurex.com/products.html) spray onto a 100%
cotton or a micro fibre towel and clean the surface
·
Optimum
Power Clean - Optimum Power Clean™ is an environmentally friendly, all
surface-safe cleaner, used for paint dilute it 2:1
·
Wurth
Clean Solve is a fast acting cleaner and solvent that will not leave a film
residue. It will quickly remove wax, tar, gum, grease, paint overspray,
adhesive, oil, and silicone. It can be used on a variety of surfaces including:
base coat, clear coat, aluminium, fibreglass, glass, fabrics and vinyl.
·
Rohm
and Haas Acrysol - a high purity solvent for cleaning a variety of surfaces,
dissolves excess adhesives, sealers, tar, undercoating, road oil, waxes and
silicone polishes.
No
residues; cleans thoroughly without leaving an oily film to attract dust and
dirt; can be applied to all types of cured paint or unpainted surfaces without
streaking or etching.
Methodology
1.
Put a drop or two of Woolite®
liquid in a clean bucket and fill it with clean water.
2.
You will need 6-inch x 4-inch sheets of Nikkens™
2000, 2500 and 3000 - grit finishing paper (1000 and 1500 grit is also
available, but they are usually used on single stage paint systems, you can start
with any grade of finishing paper according to the condition of your paint film
surface, but as always use the least abrasive first) next cut or tear three or
four pieces of the finishing papers in half and place them in the bucket also.
3.
Leave them in the bucket of water for about 20 -30 minutes to
soften their edges. These papers have a latex rubber impregnated paper backing
that is waterproof and this prevents the finishing paper from breaking-down
into pulp from over soaking. Keep the surface wet at all times and sand in
short strokes, applying light to moderate pressure with the sanding block held
flat. After going over the finish with 2000- proceed to 2500- and then switch
to 3000-grit finishing paper and sand once more.
4.
While you're waiting for the paper to soften, wash your vehicle
too completely to remove any grit or dust, and then gently dry it with clean
terry cloth towels. Next, take a tack rag and wipe over the paint surfaces one
final time to make sure the paint is absolutely clean. A small particle of grit
can make deep scratches in even the hardest finish. If you're working outdoors,
wet down the surrounding area to keep dust under control, and keep a garden
hose running with a trickle of water on the surface at all times.
5.
Use Gloss It EVP Pad Prime for surface lubrication
6.
Wrap a piece of the softened Nikkens™ 2000
- grit finishing paper (or whatever grade your paint surface requires) around a
Unigrit Sanding Block (see also alternative
products) if you're going to be working broad, flat surfaces. Otherwise, you
can just fold the sandpaper in thirds. Keep wetting the surface of the vehicle
in the area where you're sanding and keep it wet while you work. Place your
hand flat on the sanding block / finishing paper at all times and start sanding
in short, crisscross strokes.
7.
Don’t apply too much pressure to the sanding block; by flexing
the metal you’ll sand through the clear on the spots contacting the block
before the low spots disappear.
8.
Avoid applying excessive pressure; by flexing the metal you’ll
sand through the clear on the spots contacting the block before the low spots
disappear.
9.
Always keep the sanding block flat or you’ll gouge the paint
surface and never sand with just your fingertips, as you'll create grooves if
you do.
10. Only
move the finishing paper and block about 4 - inches back and forth, if you do
make a scratch, it will be a short one and easier to buff out. Using shorter,
quicker strokes requires about the same amount of time as the longer sweeps
most people are used to. Besides, you shouldn't worry about time and have a lot
of patient when colour-sanding.
11. As
the finishing paper skims over the surface it will remove the highest points in
the paint, causing them to dull, the lower spots will still have a shine; once
the high spots have been removed keep working until the paint is level.
12. Keep
the finishing paper surface clean and use a small nail brush to clean any dust ‘pills’
from the finishing papers surfacer; this will avoid any Q type pig tails. The
pills will indicate that the paper is almost ready for change
13. Regularly
lift the finishing paper and tap the sanding block with your hand to remove any
dust build up.
14. A
clean rubber squeegee (3M™ Wetordry™ Rubber Squeegee, P/N 05517, 2 -inches x 4
-inches) is the best tool for checking your progress. Swipe the squeegee across
the sanded surface periodically to clear it of water. Only when you have the
surface completely free of any suggestion of orange peel or imperfections are
you ready for the next step.
15. Proceed
to the next level of grit and repeat the process until all the coarser
scratches are eliminated and finish with 3000 - grit finishing paper in order
to remove all of the very fine scratches, only when the paint has a
consistently level, smooth, satin finish should you continue to the polishing
stage.
16. By
finishing with 2000 – 3000 grit finishing paper, less buffing will be needed to
get a flawless finish.
17. Proceed
to remove sanding scratches with a machine polisher, appropriate polish (Menzerna
PO 203 Power Finish a 2000 grit polish) and Lake Country
(LC) Mfg. Orange or a Green foam pad
18. Typically
the final step in surface polishing; using a finishing polish (Menzerna
Final Finish Polish / Super Finish 106FA) in
tandem with a pad that has no abrasive abilities (LC)
CCS Gold Concours Finishing foam) you are just effectively
burnishing the paint surface to a high gloss finish. Most finishing polishes
are formulated with lubricating oils, which enable a longer working time.
19. Spread
a finishing polish using a non-abrasive foam pad at 900-1000rpm and then
increase to 1200-1500rpm until it goes clear and then a few passes at 1000rpm.(See also Jewelling )
Notes:
1.
I wear a headlamp
when I’m wet-sanding so I can see the work area better.
2.
Maintaining a clean
work surface is of paramount importance, so wash the paint surface periodically
to remove the accumulated abrasive dust
3.
It is
also advisable to carry out a wipe-down process to ensure that there are no
polishing oils and/or abrasive dust is not ‘filling any defects, and to
determine if the surface is defect free or if further work is required
4.
Aluminium Oxide
exhibits a high degree of friability. This means that when heat and pressure
are applied it fragments. This is highly desirable because when it creates new
sharp edges, this self-renewing property allows aluminium oxide to last longer
than most other finish papers.
5.
Finishing paper
quality - cheaper paper will induce deeper sanding scratches, which will be
more difficult to remove
6.
Wet-sanding can
also be done using a random orbital polisher that has a short eccentric offset
(typically 5/16 – inch)
Alternative –
a)
Four Star Professional Abrasive Enhancing Gel, extends sandpaper
life and adds lubrication -
non-toxic, use instead of water
b)
3M™ Trizact™ Hookit™ II Clearcoat
Sanding Disc - P1500 (PN 02069)- large area wet-sanding, runs damp, long
lasting, excellent for texture matching and sanding contours, removes nibs and
other defects, leaves a very refined finish
c)
Micro-Mesh Regular finishing
papers (silicon carbide grit with standard backing) - The standard grade of
Micro-Mesh used for the majority of operations on plastics, paints, wood and
most metals and polymers. It is used to
produce a uniformly smooth surface and bring the surface to a high gloss finish. Available in grades 1500 to 12000 (30 to 2
microns)
Bi-directional sanding- if you are sanding in a \\\ pattern with the 2000, then sand in
a /// pattern with the 2500, once
all your lines are opposite then you know you have completely covered the area.
(See
also Polishing, Spit Shining, Colour, Depth and Clarity, Legal Stuff, Wet
Sanding / Polishing)
3M Nib Pad and Scalloped Disks
3M Finesse-It Hand Sanding Pad.
This 3M product is a small
(36.5mm) hand held sanding pad and is used with our 3M micron abrasive discs
typically to remove micro imperfections on the repaired dent, or can be used to
gain a "read" of the dent by flatting the top of the dent, this
usually shows any highs or lows left over.
3M™ Sanding Sponge
Soft foam sponge with
sanding abrasive coating on three sides of block form; designed for contour and
flat sanding.
Going through the grits
What does this mean?” It’s a
very similar idea to ‘Least aggressive first’ it refers to the process of using
different grit finishing papers of progressively finer grit or foam / wool pads
with progressively denser pads to get a smooth finish (i.e. using finishing
papers 500 grit increments will yield flatter results - 1000 > 1500 >
2000 > 2500 > 3000)
By going through the grits
each progressive piece of grit finishing paper or pad removes the scratches
from that previously used. Always start with the least abrasive combination,
i.e. a machine polish and the least aggressive foam / wool pad. If that
combination doesn't remove the imperfections, using the same machine polish and
change to a more aggressive pad, if the surface imperfections remain, then step-up
the abrasive polish and use the least next level (abrasive)only when the paint
has a consistently level, smooth, satin finish should you continue to the
polishing stage.
Guide Coat
Although this step is not
absolutely necessary,
I'd recommend guide coat as it provides a visual guide to a smooth surface when sanding
most primers; so you know that you got the surface level. It is certainly a
good idea if you want to achieve a really good result. Also I wouldn’t
recommend doing this with ordinary primer/surfacer as it is usually not thick
enough to rub back.
Usually a decent sized
pressure pack (SEM Gide Coat Black) aerosol will be sufficient for most cars,
the quick drying formula won't clog sandpaper just be sure it is acrylic not enamel
as enamel will react with the top coat acrylic if there is even the smallest
trace of it on the panel
·
Spray a light coat across your panels. Read the instructions and
allow enough drying time before sanding.
·
Use 800-1000 grit finishing paper used wet and with a sanding
block. Once again you want to follow the lines of the panel and keep plenty of
water on the surface. Without the use of a guide coat these imperfections would
have showed up after the top coat was on. Hence the reason to use a guide coat!
The beauty of high-fill
primer is that 99 percent of the time you can sand out these imperfections
without the need for more filler or reaching the bare surface below. Be extra
careful at the edges of the panels as it is easy to sand through the primer there
and as with the speed file, don’t be tempted just to sand one little area to
get rid of all the guide coat, keep the sanding block moving across a large
area until all the guide coat is gone. If you do happen to sand through the
primer it is simply a matter of applying some more primer and a guide coat to
the area and sanding again.
Once you think you have
sanded the entire panel wash it down with clean water and check for any
remaining guide coat, re-do any problem areas and finally either dry the panel
with compressed air or leave it out in the sun for an hour or two.
An important note regarding
primer – 99% of primer/surfacers, spray putties etc. are porous meaning that
they will absorb moisture.
The amount of time between
applying the primer and the top coat should be as little as possible and once
the wet sanding is finished be sure to dry the panel down as much as possible.
Any moisture trapped in the primer has the ability to ruin our nice new paint
job.
Final polishing
First step is to completely
remove all the sand scratch marks. Subsequent polishing steps will involve
polishing for maximum gloss and then finessing (jewelling) for maximum clarity.
You can't be in a hurry in any polishing step or you risk missing some
imperfections. It needs to be flawless.
Using a PC
1500 >2000> 3000 grit
3M Perfect-It Trizact speed 3 -4.Remove sanding scratches with a suitable
finishing polish, or use a 4-inch Purple
Foamed Wool pad and M105; followed by M105 on an LC Orange foam pad and finally
M205 with an LC White foam pad.
Personal Protective Equipment (PPE)
For your safety and the
legally required protection of employees, you will need to have personal
protective equipment available that will include a respirator fitting for you
and your employees. At no time should you endanger yourself or others, take any
unnecessary risks or infringe any laws.
Protection
from Potential Health Hazards
1.
Warning: Always use ground fault protection
interruption (GFPI) when using any electrical device around water
2.
Eye
Protection: I would strongly advise the wearing of safety glasses or visor
when operating any machine polisher.
3.
Ear
Protection; the constant pitch of a polishing machine could affect your
hearing so wearing ear plugs would be wise to protect you from hearing loss.
4.
Hand
Protection; Gloves- with the
verity of chemicals a detailer uses on a daily basis wearing chemical-resistant
gloves resist penetration and permeation, and will provide protection against
dermatitis and chemical burns. Gloves can provide protection, but they must be
chosen with care, the proper selection matched to the hazard is critical.
Chemical-resistant gloves resist penetration and permeation, and cam protect
against dermatitis, chemical burns and corrosion.
5.
Respiratory
Protection (N95): Materials such as aluminium oxide (Aluminium oxide is on
EPA's TRI list if it is a fibrous form) or silicon carbide (Nuisance
particulate-Accumulation in lungs) used in polishes and compounds, and powdered
fillers (Crystalline silica poses a serious inhalation hazard because it can
cause silicosis) and Isocyanate clear coat residue represent a hazard to your
lungs and may cause respiratory distress. Use
a NIOSH-approved half face respirator equipped with a combination filter
cartridge should be worn while using them
6.
Consult the current 3M Respiratory Selection Guide for
additional information or call 1-800-243-4630 for 3M technical assistance.
7.
Material Safety Data Sheets:
Use a ring binder or other filing system to ensure the appropriate MSDS
is always available to identify hazardous substances
8.
Work Hygienic Practices: Rinse cloves under running water before
removing them
9.
Protect
yourself, work safe. As in all things, allow common sense to prevail and proceed with due
caution
GFCI and Extension Cord
Ground Fault Circuit
Interrupter and Extension cord selection is based on two main principles.
First, the cable should be able to carry the current load imposed on it without
overheating. It should be able to do this in the most extreme conditions of temperature
it will encounter during its working life.
Second, it should offer
sufficiently sound earthing to (a) limit the voltage to which
people are exposed to a safe level and (b)
allow the fault current to trip the fuse or MCB in a short time. To meet these
requirements requires consideration of the circuit load current (AMPS) a
reasonable voltage drop, cable thickness (G) and length (feet) and the
over-current protection device
Prime Wire & Cable
Duplex GFCI -residual current device is also known as a ground fault
circuit interrupter (GFCI) junction Box with 6-Ft. cord, Model# GF200806
Portable GFCI duplex receptacle detects power leaks and shuts off electricity
in less than a second to prevent shock. Test and reset buttons Tough jobsite
box with 6-ft. 12/3 SJTW power cord UL listed, meets OSHA standards.
Prime Wire & Cable 50-Ft
extension 12/3 Neon Power Cord — Blue, Model# NS514830
Bright NEON extension cord stands out for easy identification. 12 Gauge, SJTW,
3 prong cord features super-flexible vinyl jacket with a cold temperature
rating of -31°F. LIGHTED connector indicates when power is on. Cord is water
and flame resistant and rated at 15 amps, 125V, 1875 watts, UL listed and meets
OSHA standards – Northern Tool
Bibliography
1.
Perfect-It 3000 Training Class
2.
Eastwood Technical Library - Eastwood Company Home Page
3.
Glasurit, Advice on Paint and Paintwork Defects - Glasurit
4.
Colour Sanding and Polishing - Welcome to System One APS
5.
Eastwood Technical Library - Eastwood Company Home Page
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