Auto Paint FAQ
bobs...@freenet.edmonton.ab.ca
The reason for compiling the following FAQ is to clear up some
misconceptions that are frequently posted to the newsgroups.
Some sample snippets of recent posts:
> One of the main reasons that clear coat isn't applied
to solid colors is that if you were to do this via the
same process as a two or three stage system, the paint
would be so thick it might literally fall off the car.
Solid colors are generally much thicker than their
metallic counterparts.
That post should have ended with the smiley face :) as I assume
he must have been joking. No more than five mils should ever be
applied since the expansion rate of metal and paint resins are
different. Clear coat is often applied over a color coat since
it contains the uv inhibitors that prevent photochemical
reactions with the pigment. One cannot influence the viscosity
of paint by adding a few ounces of powdered aluminum or mica.
The attached FAQ has more detail.
> Urethane enamels are quite different. Clear coats on
solid color urethane enamels isn't commonplace.
Another misconception.
Anyway the guy at the body shop said they would match
the paint and clearcoat. My question is this. Won't
the car look "off" as the factory paint is plain
urethane and the new will be clearcoated?
If the original finish is in reasonably good condition, there is
should be no difficulties in restoring the paint to "pre-
accident" condition.
Dual action sand the whole car to where the paint is so
thin that you can just barely see the original red
primer.
If you're going to strip the paint, strip it all, since the
quality of the finish is only as good as the worst coat.
Otherwise repair minor surface defects and refinish.
> If you have rubber window seals:
> Put thick electrical wire under them to lift them up.
That's the correct procedure.
Don't use too much air pressure though, paint/primer
can flake off if you aren't careful.
If you can blow the old finish off with compressed air, then take
it ALL off! How do you expect to keep the new finish on, when it
will fly off with the old paint?
=================================================================
AUTOMOTIVE PAINT FAQ.
Bob Story
bobs...@freenet.edmonton.ab.ca
This is the first posting of this FAQ which is still in draft
stage. I welcome your comments, suggestions, or questions.
1. WHAT ARE THE COMPONENTS OF PAINT?
2. WHAT TYPE OF PAINTS ARE USED ON AUTOMOBILES?
2.1 Japanese Varnish:
2.2 Nitrocellulose Lacquer:
2.3 Synthetic Enamel:
2.4 Acrylic Lacquer:
2.5 Acrylic Enamel:
2.6 Polyurethane Enamel:
2.7 Acrylic Urethane Enamel:
3. WHAT ARE REDUCERS OR THINNERS AND WHY DO WE NEED THEM?
4. WHAT IS THE BASIC TECHNIQUE OF SPRAYING?
5. WHAT DOES THE TERM "VOLUME SOLIDS" MEAN?
6. DO I HAVE TO USE A CATALYST OR HARDENER IN ACRYLIC ENAMEL?
7. WHAT BRAND OF PAINT SHOULD I USE FOR MY FIRST ATTEMPT AT SPRAY
PAINTING?
8. WHAT CAUSES RUST?
9. WHAT DO I APPLY OVER BARE METAL?
10. DO SOME COLOURS MAKE A VEHICLE SELL FOR A HIGHER PRICE, RED
FOR EXAMPLE?
11. WOULD PAINTING IT THE SAME COLOUR BE CHEAPER THAN OTHER
COLOURS?
12. IF I PAINT IT A DIFFERENT COLOUR, WILL THE OLD COLOUR SHOW
THROUGH?
13. IS NON METALLIC PAINT CHEAPER THAN METALLIC PAINT?
14. WHAT KIND OF PAINT WON'T PEEL OFF A WHILE LATER?
15. MY 91 INTEGRA GS COUPE HAS A BLACK PLASTIC BUMPER STRIP ALL
AROUND THE CAR, CAN THOSE BE PAINTED BY THE PAINT SHOP?
16. HOW CAN I (AND SHOULD I TRY TO) GO ABOUT PREPARING THE CAR
BEFORE I TAKE IT TO A PAINT SHOP.
17. I'M A NOVICE AT THIS AND NEED SOME ADVISE ON HOW TO RUB OUT
THE NEW PAINT TO GET THE "GLOSSY" FINAL FINISH.
18. WHAT IS THE BEST AND QUICKEST WAY TO STRIP THE PAINT OFF OF A
CAR?
19. WHAT SIZE AIR-COMPRESSOR DO YOU NEED TO PAINT A CAR?
20. WHAT DO YOU NEED IN THE WAY OF VENTILATION?
21. HOW MUCH PAINT DOES IT TAKE TO FULLY PAINT A CAR?
22. WHAT IS THE HVLP SYSTEM?
1. WHAT ARE THE COMPONENTS OF PAINT?
All paints consist of pigments, resins, and solvents. The resin
provides the coating material, with the pigments creating the
desired color, and solvents reduce the material to a workable
viscosity.
2. WHAT TYPE OF PAINTS ARE USED ON AUTOMOBILES?
2.1 Japanese Varnish:
In the early years, between 1900 and the 1920's,
Japanese varnishes were used. The varnish was applied
by brush.
2.2 Nitrocellulose Lacquer:
In the 1920's, several paint manufacturers were
involved in the development of nitrocellulose lacquers.
This paint had rapid drying and low viscosity
properties, and was applied with air pressure through a
spray gun leaving a hard dry finish in approximately
one hour. When rubbed, polished, and waxed, it far
surpassed in durability and appearance the qualities of
the Japanese lacquers.
2.3 Synthetic Enamel:
In the mid 1930's, a new and completely different type
of paint was developed, the alkyd or synthetic enamels.
It proved to have superior qualities in film strength,
adhesion, lustre, flexibility and durability over all
previous paints. The resin base was developed from the
reaction between phthalic anhydride and glycerin, with
gums, oils and plasticizers added during the
manufacturing process (a drying oil such as linseed, a
polyhydric alcohol, such as glycerine, and a dibasic
acid, such as Phthalic Anhydride). It dries by solvent
evaporation, like the lacquer paints, but the resin
remains soft and sticky when no solvents are present.
It cures to a hard finish by absorption of oxygen from
the air. The curing process can be accelerated by
heat, and several methods of baking enamel were
developed. Unlike lacquer, when dry, it needs no
polishing to produce a high lustre finish.
2.4 Acrylic Lacquer:
As time passed, chemists developed a substitute for
nitrocellulose lacquer, using an acrylic resin as a
base. The resins used in acrylic lacquer tend to be
slightly brittle. This deficiency is overcome by the
use of a plasticizer ( a liquid that is a solvent for
these resins and softens them slightly). A cellulosic
resin is any resin derived from cellulose (pure
cotton). Acrylic lacquer was used extensively by
General Motors.
2.5 Acrylic Enamel:
During the late 1960's and early 1970's, technology
brought on the development of acrylic enamel, which was
harder and more durable. Chemically, it is a cousin to
synthetic enamel, but is modified with acrylic resin,
and is not soft and sticky with no solvents present.
It cures further with the absorption of oxygen from the
air. Unlike the lacquers, which remain soluble in
solvents, the enamel family is insoluble in solvent
when cured. An acrylic resin is chemically any polymer
whose basic monomers are chemical derivatives of
acrylic acid.
2.6 Polyurethane Enamel:
In the mid 1970's, polyurethane enamel was developed to
withstand the severe stress of high speed airplane
surfaces, which are subject to rapid temperature
changes and flexing. This paint was much more durable
than the acrylic enamels.
2.7 Acrylic Urethane Enamel:
Acrylic urethane enamels were developed to withstand
environmental elements, such as acid rain and ultra
violet rays. It is the most durable paint to date.
3. WHAT ARE REDUCERS OR THINNERS AND WHY DO WE NEED THEM?
Aliphatic hydrocarbons (Mineral Spirits- V M & P,
Naphtha)
Aromatic hydrocarbons (Toluene, Xylene)
Esters (Ethyl Acetate, Butyl Acetate)
Ketone (Acetone, Methyl Ethyl Ketone (MEK))
Various combinations are used along with other additives
(retarders, accelerators, and levellers) to reduce the viscosity
of the material to a sprayable consistency and accommodate
climatic conditions. I recommend following the manufacturers
directions unless you have extensive experience in spray painting
automotive finishes. However, in a pinch, the general rule is
that reducers are downward compatible (i.e. you may substitute
acrylic enamel reducer for enamel reducer, but NEVER vice versa.
The solvents are weaker and you'll end up with an ugly curdled
mess in the bottom of the paint gun).
4. WHAT IS THE BASIC TECHNIQUE OF SPRAYING?
You're in the paint booth, and you've used compressed air to blow
dust from the panels, edges, beneath the mouldings and lights,
and from the masking paper and the wheel covers ( You do this
outside the booth first, then again in the booth with the exhaust
fan running, starting furthest away from the fan). You then have
washed the vehicle with a "Final Wash" or "Prep Wash" (other
washes contain silicone which cause fish eyes). You finally wipe
the vehicle with a clean tack cloth and you're ready to spray.
Occasionally, even after reducing the paint to the
manufacturers specifications it may be too dense to spray
properly. The usual specs is about 15 seconds in a #4 Ford
viscosity cup. Translated into English, that means about 4
seconds to stop dripping off the end of the stir stick. Turn
your regulator to about 50 lbs, and get a nice oval pattern.
Trigger the gun so that air passes through the cap, but no fluid
comes through. Holding the tip of the gun about 8 - 10 inches
perpendicular to the surface, start your pass along the panel at
a hand speed of about one foot per second and squeeze the trigger
to allow fluid. At the edge of the panel, release the trigger to
stop fluid but still allow air. This constant air flow ensures
that the air is not pulsing with bursts of pressure. This could
cause excessive build up at the ends of you pass, leaving runs
and sags. Don't stop at the edge of panels either, as this will
also cause build up of material. On the back stroke, overlap
half the first pass (the edge of the paint should appear dry, and
the centre wet. This is known as a "medium wet coat"),
triggering the gun as before. Always begin painting furthest
away from the exhaust fan, so that you are painting over the
overspray. Otherwise, overspray will settle onto the painted
areas and may not blend in, leaving the surface dry and dull in
appearance. With base coats, wait until the coat of paint is DRY
before applying the next coat. Otherwise wait until it is almost
dry, but a little sticky (the directions are usually close).
5. WHAT DOES THE TERM "VOLUME SOLIDS" MEAN?
On the technical data sheet, volume solids refers to the
percentage of actual film formers in the paint. The remainder is
lost to evaporation. (e.g. 32% solids means that 32% of the
material applied forms the coating; 68% is reducer or thinners).
6. DO I HAVE TO USE A CATALYST OR HARDENER IN ACRYLIC ENAMEL?
You should, to speed up the curing time of the paint. However,
acrylic enamel will cure over time by absorbing oxygen from the
atmosphere to complete the molecular cross linking needed to
create the polymer. The addition of a catalyst accelerates this
process greatly (a few days versus a few months without a
catalyst agent).
7. WHAT BRAND OF PAINT SHOULD I USE FOR MY FIRST ATTEMPT AT SPRAY
PAINTING?
All major brands of paint perform well. Personally, I would
suggest that a novice or first time painter should use Dupont
acrylic enamel ("Centari" (tm)). It is one of the most forgiving
paints, as it dries quickly, melts in overspray well, and does
not run easily. These positive features outweigh the negative
effects of quick dry times, which are mentioned elsewhere in this
FAQ. I don't know if they still make it, but Deltron(tm) by PPG
is also an excellent product for a first time attempt.
8. WHAT CAUSES RUST?
Corrosion is caused when an area of metal has a positive charge
and another has a negative charge. Water acts as an electrolyte,
allowing current to flow between these areas. During this
process the metal absorbs oxygen from the water and forms iron
oxide (rust). Salt water conducts electricity better than fresh
water so in areas that use salt on the roads, this process is
greatly accelerated. The objective of applying a protective coat
of paint is to insulate the metal from water. To ensure that no
rust is present before we coat the metal, we clean the metal with
an acid (phosphoric based, which leaves a thin film of iron
phosphate or zinc phosphate that prevents flash rusting), and
then apply a zinc phosphate coating which neutralizes the acid,
and promotes primer adhesion. Zinc (galvanized and zinc rich
primers) competes with the iron for oxygen, and becomes the
sacrificial metal which corrodes, leaving the iron undamaged.
9. WHAT DO I APPLY OVER BARE METAL?
Use a zinc chromate primer which is essentially a metal
treatment. Follow this with a good quality primer surfacer (a
brand name that requires a catalyst (urethane or epoxy)). All
the major manufacturers use a form of a seven stage process
before priming.
1. Hot detergent wash to remove grease and oils.
2. Water rinse to remove the detergent, since the detergent
interferes with acid.
3. Acid wash to remove scale and open pores in metal.
4. Water rinse to remove acid.
5. Zinc phosphate acid treatment for corrosion protection and
paint adhesion.
6. Water rinse to remove acid.
7. Bake dry.
This is followed by a primer coat of melamine polyester resin
(Japan), polybutadiene (Europe), or a polyester or epoxy ester
system (USA).
10. DO SOME COLOURS MAKE A VEHICLE SELL FOR A HIGHER PRICE, RED
FOR EXAMPLE?
I don't know. I don't sell cars. I paint them.
11. WOULD PAINTING IT THE SAME COLOUR BE CHEAPER THAN OTHER
COLOURS?
Of course, painting the jambs, door posts, and underneath the
deck and hood will increase the labour hours. Other than that,
it is simply a matter of colour. Pigment is the determining
factor in the cost of paint. Blue, for example, is made from
cobalt, which is relatively inexpensive. Red pigments are by far
the most expensive, perhaps three times the cost of whites
(titanium dioxide).
12. IF I PAINT IT A DIFFERENT COLOUR, WILL THE OLD COLOUR SHOW
THROUGH?
If the old finish is of poor quality (enamel or lacquer), you
must use a sealer to separate the two finishes. Sealer is an
inexpensive insurance policy to prevent "colour bleeding", which
was quite common with enamel reds during the sixties.
13. IS NON METALLIC PAINT CHEAPER THAN METALLIC PAINT?
No. Metallics are made with the addition of crushed aluminum
and/or mica, and is not expensive. However, some pearls which
are used in the new tri-coat systems are quite costly.
14. WHAT KIND OF PAINT WON'T PEEL OFF A WHILE LATER?
The technical term is "delamination". There are two methods of
paint adhesion. Chemical and molecular attraction. Properly
prepared surfaces and substrates, and properly applied coatings
should have excellent adhesion. Why then, are there so many
instances of peeling paint in recent years? The problem seems to
be in the quest to meet increasing VOC (volatile organic
compound) emissions by using water borne or water based low VOC
products. The topcoat should slightly penetrate into the
substrate and "bite" into it with a good chemical adhesion.
Unfortunately, this does not seem to be the case when working
with incompatible solvents.
15. MY 91 INTEGRA GS COUPE HAS A BLACK PLASTIC BUMPER STRIP ALL
AROUND THE CAR, CAN THOSE BE PAINTED BY THE PAINT SHOP?
All interior plastic parts can be painted except for PC
(Polycarbonate) because the integrity of the material is
compromised by the paint. To my knowledge all exterior plastic
parts can be painted. These parts are identified by a code list
on the back of the part, or by a flame test.
ABS (Acrylonitrile/Butadiene/Styrene)
CPE* (Chlorinated Polyethylene)
EP Epoxy
E/P EPM* Ethylene/Propylene
EPDM* Ethylene/Propylene Diene
E/VAC* Ethylene/Vinyl Acetate
MF Melamine
PF Phenolic
PA Polyamide (Nylon)
UP Unsaturated Polyester (SMC) Thermoset
PE* Polyethylene
PPYO/PPO Poly (phenylene Oxide; Phenoxy, Polyaryl Ether) Noryl
PP* Polypropylene
PUR* Thermoset Polyurethane
TPO, TPR* Thermoplastic (Olefin, Rubber)
TPUR* Thermoplastic Polyurethane
PVC Polyvinyl Chloride
SAN Styrene Acrylonitrile
UF Urea Formaldehyde
* requires a flex additive for top coat.
16. HOW CAN I (AND SHOULD I TRY TO) GO ABOUT PREPARING THE CAR
BEFORE I TAKE IT TO A PAINT SHOP.
I want to be cautious dispensing advice on this subject, since it
is easy for someone who is inexperienced to create more work by
attempting to do too much them selves. Body shop costs are
calculated from the hourly rate the shop normally charges
multiplied by the hours required to do the work based on Mitchell
Guide Flat Rate manuals. Let's say the hours required to
refinish a car is quoted at 23 hours, multiplied by a shop rate
of $42.00/hr, plus an additional charge of $19.00/hr for paint
materials, we would arrive at a cost of $1403.00 plus any
applicable taxes. Body work is extra, usually quoted at the shop
labour rate plus an additional charge of $9.00/hr for shop
materials. To reduce some of the labour time, one could remove
all chrome and trim that has to be removed for painting. If the
sheet metal is straight, then sanding with 180 grit or finer
would also cut down the labour costs. But then again, putting
additional divots with the sander, or denting the sheet metal
while removing the trim will only increase the labour hours. I
would suggest consulting with the body shop that you intend to
use, as to what you can do. How much and what you decide to do
is at your own discretion.
17. I'M A NOVICE AT THIS AND NEED SOME ADVISE ON HOW TO RUB OUT
THE NEW PAINT TO GET THE "GLOSSY" FINAL FINISH.
You will need a 7" grinder, Mcguires #4, and #7 compound, a
bucket of clean water, a stiff foam sanding block, and some
sheets of 10 micron (1500 grit) wet sandpaper. Do not attempt to
polish in direct sunlight. If the paint is non-metallic or clear
coated, then wet-sanding is recommended. Do not attempt to sand
a metallic paint that has NOT been clear coated as you will
disturb the metallic pattern. Wash the car thoroughly. Get some
10 micron (1500 grit) wet sandpaper, and fold three or four
sheets into three sections so that none of the abrasive sides are
touching (from the back, left side in two thirds, right side in
one third) and put it into a bucket of CLEAN water. Have a
coffee or a beverage and do nothing for about twenty minutes.
This will allow the sandpaper to become soaked and flexible. If
you omit this step, you will likely put deep paper cuts into the
paint that won't polish out. Use a firm foam sanding block, keep
the surface wet and sand the surface, squeezing the water off
every once in a while with the sanding block to check for
imperfections in the surface. Stay away from edges or high crown
lines, as the polishing wheel will burn through these areas very
quickly. Once you are satisfied, put a clean wool polishing pad
on (if it has old polish on it, then spin the pad and clean it
with a dressing tool or something that's clean and not sharp),
and apply some #4 Mcguires onto the pad. Polish the surface,
moving the pad steadily to prevent heat build up (except for
lacquer, which can be reflowed). In a few minutes you will see a
good shine develop. Continue with the remaining panels. Put on
a foam pad, and use #7 compound, to bring up a deeper shine and
eliminate any swirl marks. Wash off any compound residue when
finished.
18. WHAT IS THE BEST AND QUICKEST WAY TO STRIP THE PAINT OFF OF A
CAR?
The most common methods of paint removal are sandblasting,
plastic blasting, chemical stripper, or sanding. Sandblasting is
not recommended as it tends to create heat and warp the sheet
metal, which creates a whole new set of problems. Plastic
blasting is good, but expensive. Chemical stripper is fairly
inexpensive and fast, but it is quite messy and be sure to mask
or remove all the trim and plastic lens coverings. Additionally,
caution must be used to avoid skin or eye contact which could
result in severe injuries. A dual action sander (set to strip
mode) with 80 grit paper will do the job nicely, although it may
take a while. Follow with 180 in oscillating mode to remove the
circular patterns in the sheet metal.
19. WHAT SIZE AIR-COMPRESSOR DO YOU NEED TO PAINT A CAR?
The compressor should be capable of delivering a minimum 20 cfm
at 90 psi.
20. WHAT DO YOU NEED IN THE WAY OF VENTILATION?
Nearly all the materials used in automotive refinishing are
hazardous to your health, the paint especially so. The catalysts
usually contain Diisocyanate Prepolymer, and it's the isocyanate
that is the main concern. It attacks the central nervous system,
and can cause permanent injury. A good air flow, and a fresh air
mask should be used. If you don't have any bronchial problems,
then an activated charcoal mask can be used. I have used the
charcoal mask for years, but now my lungs seem to have an
asthmatic reaction to the fumes and I strictly use the fresh air
system.
21. HOW MUCH PAINT DOES IT TAKE TO FULLY PAINT A CAR?
It depends on the size of the vehicle, and the type of paint
used. There are formulas for sq. ft. coverage, but in my
experience are not always reliable. Let's take a 92 Cutlass
Ciera for example, which would be a fairly common size. In a
base coat/clear coat (BC/CC) application, I would mix 2 quarts of
basecoat, which thinned to spraying consistency would give me a
gallon of sprayable material, and should provide adequate
coverage. However, some pigments are more transparent than
others, and additional or less material may be required. Paint
booth lighting is essential to ensure proper coverage. After
applying the base coat, I would mix two quarts of clear, which
reduced would give me three quarts of sprayable material (two
coats at approx 1 1/2 quarts per coat). An additional third coat
could be applied if desired, but be sure to watch for excessive
film build which can lead to dulling or solvent popping problems.
If you don't have access to a paint mixing system, then buy more
than you need. There is no way to fix a paint job that does not
have adequate coverage except for repainting the entire car.
22. WHAT IS THE HVLP SYSTEM?
A High Volume Low Pressure system designed to increase transfer
efficiency by eliminating excessive over spray, which creates
high VOC emissions and material waste. Sort of like volts * amps
= watts. Conventional spray systems operate at about 50-60 psi
and the HVLP system requires less than 10 psi. HOWEVER, the same
amount of air is consumed. If you don't have large air lines the
volume of air will be restricted, and it won't work. As a simile
we can imagine a small garden hose with high pressure versus a
large hose with small pressure that are designed to flow an equal
amount of water. That is likely the main reason they never
became very popular. The painters used them once, swore at them,
and hung them up on the wall to collect dust, without realizing
that the 3/4" reduced to 1/2" shop air lines simply were not
designed to carry an adequate VOLUME of air.
--
bobs...@freenet.edmonton.ab.ca
Klint Karch
Thanks Bob! Good scoop.
Klint
Bernie H. Krause
Hi, Bob. Sorry, but anyone who sounds that knowledgeable(?)
about a subject is just asking to be pestered with more
questions, so here's mine. Hope you don't mind.
I've got a 1993 Taurus wagon, with a strange paint problem which
body shops here can't agree on. The car is white, and the upper
surfaces (roof, hood, fender tops) are covered with a very, very
fine pin point sprinkling of rust coloured spots. They aren't
obvious until you're looking at the car from about 6 inches away,
then they're everywhere. There are some on the perpendicular
surfaces (doors, back hatch) but none in none exposed areas such
as between the doors, on the door pillars, etc. Some bodyshops
have said "It is rust!", others say "It is Not rust", others say
"I don't know what it is". I've heard the term 'railroad dust'
mentioned at a few places. The spots can be taken out with
rubbing compound, and don't seem to leave pit marks in the paint,
so I'm guessing that it isn't rust, but some residue from
something else.
Any opinion or experience with this?
TIA
Bernie Krause
Winnipeg
Don Sterner
In article <4vnigd$1p...@bottom.MTS.Net>, Bernie H. Krause said...
I've seen that symptom twice. In one case the vehicle was regularly
parked near a busy railroad. In the other case, a pickup was
regularly parked near an incinerator. The concensus was that the
'rust' was caused by metal particles that fell onto the surface
of the vehicle.
Be very careful of that rubbing compound!
--
dste...@neosoft.com
Sumo Rabbit
"Bernie H. Krause" <bkr...@mts.net> wrote:
>I've got a 1993 Taurus wagon, with a strange paint problem which
>body shops here can't agree on. The car is white, and the upper
>surfaces (roof, hood, fender tops) are covered with a very, very
>fine pin point sprinkling of rust coloured spots. They aren't
Sounds like metal particles are settling on your car and rusting.
Look for sources of airborne metal particles in areas where you
regularly park your car. (it's often called "railroad dust" because
that's a big source). Construction sites, railroad tracks, or even a
nearby metal shop. Depending on the nature of the stuff, a good coat
of wax might help you wash off the dust, rather than having to resort
to a rubbing compound.
Good luck!
Andy
Matthew McDonald
"Bernie H. Krause" <bkr...@mts.net> wrote:
>Hi, Bob. Sorry, but anyone who sounds that knowledgeable(?)
>about a subject is just asking to be pestered with more
>questions, so here's mine. Hope you don't mind.
>
>I've got a 1993 Taurus wagon, with a strange paint problem which
>body shops here can't agree on. The car is white, and the upper
>surfaces (roof, hood, fender tops) are covered with a very, very
>fine pin point sprinkling of rust coloured spots. They aren't
>obvious until you're looking at the car from about 6 inches away,
>then they're everywhere. There are some on the perpendicular
>surfaces (doors, back hatch) but none in none exposed areas such
>as between the doors, on the door pillars, etc. Some bodyshops
>have said "It is rust!", others say "It is Not rust", others say
>"I don't know what it is". I've heard the term 'railroad dust'
Sounds like 'Railroad Dust'.. do you park near a train station or near
tram tracks.. I've seen the problem in Australia when parked near
tracks.. When the tram or whatever brakes it throws tiny particles of
RED HOT metal around and when it lands on the car it settles in the
paint and after a few days starts to rust. It can apparently be buffed
out. It's more apparent on light colored cars..
regards
matthew
|\ /|
--------------- \ / ---------------
Matthew McDonald \ / Email:
Tasmania Australia \ www.sv.net.au/~matthew / mat...@sv.net.au
+61 41 Matthew / GSM and Piazza Info \ Files etc:
+61 416 288 439 / \ mat...@trump.net.au
_______________ / \ _______________
|/ \|
bobs...@freenet.edmonton.ab.ca
Matthew McDonald (mat...@sv.net.au) wrote:
: "Bernie H. Krause" <bkr...@mts.net> wrote:
: >body shops here can't agree on. The car is white, and the upper
: >surfaces (roof, hood, fender tops) are covered with a very, very
: >fine pin point sprinkling of rust coloured spots. They aren't
: Sounds like 'Railroad Dust'.. do you park near a train station or near
: tram tracks.. I've seen the problem in Australia when parked near
Yes, I agree with the railway dust. Except that the dust is caused when
the trains wear tiny particles from the track, and these fine particles
float into the air. They are not hot, but they turn to rust very
quickly, and do no real damage other than appearance.
--
bobs...@freenet.edmonton.ab.ca
Tracy Nordin
Bernie H. Krause wrote:
>
> Hi, Bob. Sorry, but anyone who sounds that knowledgeable(?)
> about a subject is just asking to be pestered with more
> questions, so here's mine. Hope you don't mind.
>
> I've got a 1993 Taurus wagon, with a strange paint problem which
> surfaces (roof, hood, fender tops) are covered with a very, very
> fine pin point sprinkling of rust coloured spots.
I have read several replies mentioning "railroad dust". Another
source of these rust colored spots can come from parking under
a sycamore tree during the summer months. The tree developes some
sort of brown "stuff" under it's leaves. When it rains this
dust will form little brown dots on light covered vehicles that
is real difficult to remove. I parked a white fiberglass boat
under my tree once, at I had to sand the junk off. Maybe the
indians of old used this for "permanent" ink.
Richard Nottage
In a previous article, bkr...@mts.net ("Bernie H. Krause") says:
>Hi, Bob. Sorry, but anyone who sounds that knowledgeable(?)
>about a subject is just asking to be pestered with more
>questions, so here's mine. Hope you don't mind.
>
>I've got a 1993 Taurus wagon, with a strange paint problem which
>body shops here can't agree on. The car is white, and the upper
>surfaces (roof, hood, fender tops) are covered with a very, very
>fine pin point sprinkling of rust coloured spots. They aren't
>obvious until you're looking at the car from about 6 inches away,
>then they're everywhere. There are some on the perpendicular
>surfaces (doors, back hatch) but none in none exposed areas such
>as between the doors, on the door pillars, etc. Some bodyshops
>have said "It is rust!", others say "It is Not rust", others say
>"I don't know what it is". I've heard the term 'railroad dust'
>mentioned at a few places. The spots can be taken out with
>rubbing compound, and don't seem to leave pit marks in the paint,
>so I'm guessing that it isn't rust, but some residue from
>something else.
> Any opinion or experience with this?
>
>TIA
>
>Bernie Krause
>Winnipeg
>
>
The most likely source of these rust spots is Brake dust.
With semi metallic pads on most vehicles, you can Imagine how much metal dust
becomes airborne.
I have noticed this problem on my White Grand Prix mostly on the nose and rear
lite and bumper area.
I speculate the nose contamination is from following other cars and the rear is
from wind turbulance (sp?)