enamel paqint

8/7/2019 enamel paqint

1/22

What Is Enamel Paint?By Stevie Donald, eHow Contributor

What Is Enamel Paint?

Enamel paint usually refers to any hard, glossy, opaque finish. Consider tooth enamel or nail

polish enamel used for fingernails and toenails, as well as paint. Traditionally, enamel paints

were defined as oil-based enamel, but since water-based paints have become so common, the

term is usually used for any glossy paint used on trim, kitchens, bathrooms or anywhere a

durable, shiny finish is desired. However, to confuse matters, some manufacturers sell "flat

enamels," which can make this a hard term to define.

Types1. Enamel paints are any that are hard, washable and usually glossy. They can be oil-based or

alkyd-based, which dry slower and harder than water-based enamels. Oil-based paints have a

strong solvent odor, and all cleanup is done with paint thinner or mineral spirits. Water-based

(also called latex or acrylic) paints are easier to use, dry faster and have a fairly low odor.

Enamels may also be urethane or polyurethane, in either water or a solvent base. Enamels

typically come in several sheens, from eggshell or low-luster to satin, semigloss and high-gloss.

Specialized enamels, often faster-drying, are used for painting appliances and flooring. Some

enamels are heat-resistant.

Misconceptions

2. Before latex paints were available, most paint manufacturers produced what they called "flat

enamels," which were a hard, oil-based flat paint that withstood cleaning and scrubbing. Many

washable water-based flat paints are now marketed as flat enamels, meaning that they have little

or no sheen, but are still very durable and scrubbable. This is not technically correct, but a

marketing term, because most consumers assume any enamel paint will be washable.

Function

3. The higher the gloss of any paint, the harder it dries. Enamel paints are used in the home on any

surface that must withstand high traffic, humidity or grubby hands. Trim, doors, bathroom,

kitchens and floors are painted with enamel because they withstand more abuse, are moisture-

resistant and can be washed repeatedly without marring the surface. Enamels are also used on

appliances, painted furniture and industrial applications.Automobiles, boats, parts of airplanes

and even space shuttle components are finished with enamel paint.Considerations

4. Enamel paints can be applied by brush, roller or spray equipment, depending on the type of paint

and purpose. Follow label directions for application methods and drying time, and remember that

in almost all cases, several thin coats are better than one or two thick coats. When using any

glossy paint, bear in mind that the higher the sheen, the more surface imperfections will show, so

proper preparation is important.

Expert Insight


2/22

5. While oil-based enamel reaches optimum hardness in 8 to 24 hours (depending on drying

conditions), water-based enamel takes up to a month to cure and are somewhat easier to mar

until cured, so care must be taken with washing and handling. Oil-based enamels dry from the

inside out, so when they feel completely dry to the touch, they are fully cured. Water-based

enamels dry from the outside in. A skin forms on the surface of the paint, so it feels dry to the

touch within an hour. However, the underlying paint film dries very slowly. In humid or coolconditions, it can take several weeks to fully harden.

Read more: What Is Enamel Paint? | eHow.comhttp://www.ehow.com/about_4618401_what-enamel-

paint.html#ixzz1FuTx3FnC

Enamel paints are a kind of hard paint with a glossy finish. Enamel paints can be made by adding varnish in ordinaryoil-based paint. In 1930 oil modified polyesters were introduced. These polyesters are sometimes referred to as enamel

paints. Typicallyenamel paint is used to refer to a wide range of high gloss oil-based covering products. Enamel

products also include latex or water based paints. Modern enamel paints are hard surfaced and is usually in reference

to high quality paint brands, floor coatings with high gloss or spray paints.

Varieties of Enamel Paints: There is a wide range of enamel paint available in the market, namely;

Floor Enamel: it is used for concrete surfaces, stairs, basements, porches and patios.

Fast Dry Enamel: fast drying enamels dry within 15-20 minutes of their application. They are ideally used for painting

refrigerators, counters and for other industrial finishes.

High-temp enamel: high temperature enamel paints are extremely heat resistant. They are used to paint engines,

brakes, exhaust and barbecue grills.

Anti rust enamel: used for painting rust susceptible items.

Enamel paint is also used on wood to make it resistant to external elements through the waterproofing and rot proofingcharacteristics of enamel. Enamel painted surfaces are longer lasting and more resistant to wear and tear than

unpainted or untreated surfaces.

Spray Paints:

Spray paints are essentially enamel paints. The most popular type of spray paint is available in aerosol cans.Automobile painting shops use air compressors to spray paint a car body. These are expensive and laborious. Ordinary

spray guns have a compressor to atomize the paint. This type of spray gun wastes a lot of paint since one third of thepaint is coated and the rest is blown into the air as a result of which it makes the job very messy.

Alternative varieties of Enamel Paint:

Other varieties ofenamel paints available in the market are acrylic enamel paint, latex enamels and oil based

enamel paints


3/22

Enamel paint is extremely tricky to use. It's a very unpredictable medium but once perfected, its

advantages are unachievable by other painting media. It has a long-lasting slick-shine, glossy or semi-

glossy finish that sticks well to metals like gold and copper, stones, jewels and ceramics depending on the

fusion tendencies of the materials. It can be used in different art projects including fresco painting, jar

designs, furniture, hand-crafted items like earrings, charms and bracelets, pocket watches and other kindsof jewelry. That process of enameling jewelry is a method that is able to create fine, intricate images using

glass powder that is thinly crushed and heated.

It has been established that enamel is complexly applied on materials to create one-of-a-kind little pieces

of adornments, decorative objects like lawn gnomes, fancy plates for display, and statues. It can also be

used to paint cookware, kitchen pots and professionally made handcrafted kitchenware.

If you want to try your hand at enamel painting, here are a few steps to follow:

1. Prepare your area. Select a workplace where enamel can dry better and where there is good

enough ventilation to prevent suffocation or light-headedness from the potentially harmful

chemicals that exude from the enamel.

2. Start by applying a coat of primer on the material. This keeps it from growing mold, rustingand warping in time. It also keeps the following coat of enamel smooth and glossy when

painted over the material.

If spray paint is unavailable, always use a clean, new varnishing brush that is free of dust and

foreign elements that may stick onto the canvass or material. Ensure this by rinsing it with

turpentine prior to use. For jewelry that requires painting fine details, use a fine, pointed

brush. Be certain of the details you are going to put into your work before applying enamel

because enamel is thicker than water-based paint, making it hard to remove if alterations are

to be done. You may now begin painting. Adding thinner into the mixture will remedy this

by regulating the consistency of the enamel and helping it spread smoothly and evenly across

the surface of the material.

Industrial Enamel Application

On sheet steel, a ground coat layer is put on first to create adhesion. The only surface preparation

required for modern ground coats is a simply degreasing of the steel with a mildly alkaline solution.

White and colored second "cover" coats of enamel are applied over the fired ground coat. For

electrostatic enamels, the colored enamel powder can be applied directly over a thin unfired ground

coat "base coat" layer that is co-fired with the cover coat in a very efficient two-coat/one-fire process.

The frit in the ground coat contains smelted-in cobalt and/or nickel oxide as well as other transition

metal oxides to catalyze the enamel-steel bonding reactions. During firing of the enamel at between

760 to 895 C (1400 and 1640 F), iron oxide scale first forms on the steel. The molten enamel

dissolves the iron oxide and precipitates cobalt and nickel. The iron acts the anode in an

electrogalvanic reaction in which the iron is again oxidized, dissolved by the glass, and oxidized again


4/22


5/22

Enamel (glass) is crushed

to a powder somewhat finer than granulated sugar and somewhat

coarser than flour. This powder is applied, by one of several

methods, to the metal surface. Next, the article is heated to 1000-

1600F, either in a preheated furnace, or with a hand-held

torch. After 1-1/2 to 10 minutes, the article is removed and allowed

to cool to room temperature. Subsequent coats, normally different

colors, are applied. Sometimes 10-20 firings are required to bring

about the desired results.

What is it's history?We do not know when or where enameling originated. The

earliest known enameled articles are six enameled gold rings

discovered in a Mycenaean tomb at Kouklia, Cyprus. The rings

date from the thirteenth century B.C.


6/22

The Greeks were enameling gold jewelry as early as the5th century B.C. Caesar found the Celtic inhabitants of

Britain enameling in the 1st century B.C. During theByzantine era, 4th through 12th centuries, numerous enamel

religious works were made. Fifteenth century artisans in

Limoges, France, perfected the use of enamels in a painting

technique. The 17th, 18th and 19th centuries and the early

decades of the 20th century saw the production of a great

volume of luxury and decorative enamels, made in many

different centers. Since the last third of the 19th century, both

Japan and China have exported an abundance of enamel as

cloisonn - the name of the technique.

Starting early in the 19th century, it was realized enamel

could be used for utilitarian purposes. First in pots and pansfor cooking, then stoves, refrigerators, kitchen sinks, bathtubs,

home laundry appliances, architectural panels, etc.

Who Does it?


7/22

Utilitarian enamels are

made in large factories, while artistic enamels are made by

thousands of individual artists throughout the world. We see

enamels exhibited at schools, arts and crafts shows, artgalleries, museums, and rare examples have sold at auction for

more than 3-1/2 million dollars.

What is a quality enamel?

A quality work of

enamel art should have a sense of design, a feeling for

proportion and appropriate color and texture.

Transparent enamels should be jewel-like. Firing of all

enamels should be sufficient to insure a permanent bond ofglass to metal. The work should show that the artist has full

control of the technique and materials.


8/22

Enamel Preparationby Woodrow W. Carpenter

Volume 1, Number 2, March 1982Discuss this article in the Glass on Metal Forums

The traditional method of enamel preparation was described by Cunynghame1 and

Chapin2. Large chunks of enamel were wrapped in a piece of cloth and broken with a

hammer. The cloth was to prevent the particles from flying about, getting into one's eye or

being lost. When the enamel had been broken into pieces about the size of a pea, they were

washed to remove any lint. Quoting Cunynghame verbatim: "The enamel is placed in a very

hard mortar, about 8 inches in diameter, preferably of Scottish or Villon granite, with a pestle

of the same material. A little clean water is poured on to it, to prevent the chips from flying,

and then it is pounded into small pieces with the aid of the mallet. The mortar may be laid on

a bag of sand to prevent its being broken by the shock. Afterwards the enamel is ground upwith the pestle to the size of ordinary sea sand." Two paragraphs later: "After the enamel

begins to become as small as sand, a milky substance seems to be disengaged and to fill thewater, which lies above the enamel. This consists of some of the colouring matter of very

fine particles of enamel and of potash and soda. If any of it is left in, the enamel when firedwill be opaque and dull. Hence it must be washed away by agitating the pounded enamel in

water poured into the mortar and then pouring off the fluid. This must be done until theenamel remaining is in fine even grains, looking like perfectly clear, clean, fine sand. The

size of the grains may be such as will go through a fine sieve with meshes 75 to the linear

inch." Five paragraphs later: "Opaque enamels need not be washed, except to remove any

little dirt that may have got in, and, as will presently be seen, some coatings of enamel cannot

be washed, but must be put on in a state of impalpable powder. So thin, however, are the

layers thus used that they are fused up into transparent enamel." As far as we can determine,

he did not expand on this statement presently or later. If he had, he probably would have said

that low firing enamels made at this time were practically water soluble.

Unfortunately, the art-enameling community has always been isolated from the glass and

enamel scientists. As a result, Cunynghame cannot be criticized, because he did not have the

benefit of knowledge gained during the eighty years following publication of his book.

During the last decade of the nineteenth century, glass scientists became very involved

with the durability of glass. The first published work of note was by Foerster3 in 1893. Much

has been published up to the present. A few of the major works are listed as references.

Let us start with the enamel as it is removed from the pot and poured onto a metal plate to

cool. At this stage, it is a round flat disk perhaps eight inches in diameter and one half inch

thick. Depending on the composition, some are quite durable as to water, acid andalkali. Others are not so durable. In any case, they all are at their maximum durability at this

moment. Surface tension caused the glass to assume a minimum volume, thus tightening the

network structure at the surface, forming what we might call a fire polished surface. Any free

alkali at or near the surface is vaporized, resulting in a skin which is a little more durable than

the interior.


9/22

When cool, the enamel cakes are ground or crushed. The normal European method is ballmilling, while the normal method in the United States is crushing with hardened steel

rolls. The principle advantage of the latter method is fewer fines are produced.

Ground enamel is slightly less durable than the cake or lump form. When two immiscible

phases, such as a gas and a solid are brought into contact, the solid will adsorb a thin film of

the gas.

Adsorption is to be distinguished from absorption, which involves the bulk penetration of

the structure of a solid by a gas and is governed by laws of diffusion.

Air is a gas which normally contains some water. Thus, at certain humidity andtemperature conditions, all solid surfaces will adsorb a thin film of water. A fire polished

surface will adsorb only a thin layer, known as physical adsorption. Such layers are weaklybonded and can be removed by a slight increase in the temperature of the solid.

When glass is broken, an atomically clean surface is exposed. Immediately, this clean

surface reacts with the air by a process known as chemisorption. If the certain humidity and

temperature conditions mentioned above exist, the surface will adsorb a thin film ofwater. Unlike physical adsorption, chemisorption consists of strong bonds and the water

cannot be removed by a slight increase in the temperature of the glass.

The thin film of water reacts with the glass. First is an ion exchange of alkali and

hydrogen ions (explained below), and second, the formation of sodium hydroxide and/or

sodium carbonate. If the humidity and temperature conditions change, the sodium hydroxide

and/or sodium carbonate may crystallize and cease to react. If conditions change so the

crystals can absorb water, reaction will restart.

The extent of the reaction depends upon the composition of the enamel, and theprecautions exercised by the manufacturer, distributor, and enameler.

The scene now switches to the enameler's studio. According to most books, all enamels

are immediately washed and stored wet, in small jars or bottles.

At least three different steps are involved in the reaction of water with ground

enamel. The first, is ion exchange of hydronium (H3O+) or hydrogen ions from the water with

alkali ions in the glass. Second, is the partial hydration of the silicon-oxygen network of the

glass. Third, is the dissolution of the glass into the contacting solution.


10/22

Figure 1 is a schematic diagram showing water in contact with one surface of glass,

assuming the other surfaces are protected. The dry glass at the bottom, contains alkali ions at

the original concentration.A

s one proceeds upward to the glass surface, there is a decrease inthe concentration of alkali ions (dotted S curve) as a result of their replacement withhydronium ions. In this layer of partial exchange, the network structure of the glass is intact,

and the only change is replacement of one ion for another. Closer to the surface, the networkcan become partially hydrated by reaction of silicon-oxygen bonds with water.

This partial hydration leads to a more open structure than in the original glass; ions from

solution and water molecules can penetrate through this partially hydrated or gel layer with

mobilities much higher than in the glass network that has not been broken up by reaction. (1)

The exchange of alkali ions in the glass and hydronium ions from water can be described

with the equation: Na+ (glass) + H3O+ (solution) = Na+ (solution) + H3O+ (glass). (2)


11/22

As reaction (2) proceeds the solution becomes more basic, and the rate of dissolution ofthe silicon-oxygen network becomes more rapid.

At extended time of reaction, the amount of alkali appearing in solution becomes

proportional of time. Furthermore, silicon and other glass constituents are found in the

solution. These results suggest that the glass dissolves into the solution by reactions of the

type:

2 H2O + SiO2 = H4SiO4 (3)

H2O + CaO = Ca(OH)2 (4)

3 H2O + A12O3 = 2A1(OH)3 (5)

H2O + Na2O = 2 Na(OH) (6)

H2O + PbO = Pb(OH)2 (7)

In reaction (2), the sodium cation (ion with a positive charge) was used as an illustration

because it has the greatest mobility in a glass network. Actually, all cations react with thehydrogen ion as shown in reaction (2), but at different rates.

The rate of the above reactions depend greatly on the composition of the enamel and tosome extent on the amount of water used, as well as the temperatures of storage, and whether

or not the jar is tightly sealed. When a sufficient amount of the enamel has been dissolved,

the mass will 'set up' like concrete. Enamels have been made with durability so low that they

would 'set up' in a matter of days. Enamels can also be made with durability so high that it

takes years.

Since the attack is proportional to time, it is obvious that fine particles would be

completely changed to a gel before large particles. The composition of the gel will vary

some, depending on the composition of the enamel. In any event, it is composed of metal

hydrates which will not form a glass at a normal firing temperature. Therefore, it is desirable

to remove the fine particles which have a high degree of deterioration. The custom has been

by elutriation as described by Cunynghame. This does not remove the gel or deterioration

from the larger grains, which may give off water up to 1000F or higher, leaving metal salts

which will not be taken into solution by the glass at normal firing temperatures, resulting in

white specks. If some combination of acids and/or alkali could be used to completely

dissolve the gel, there remains that portion of the glass where there is a partial exchange of

hydrogen ions for alkali ions. Once most of the hydrogen ions and water molecules havebeen driven out with heat, there remains a silica rich area which is more refractory and of a

much lower expansion than the bulk of the glass. This part of the glass will have a dullappearance and some opacity due to some water being retained. Perhaps these silica rich

areas can be removed with hydrofluoric acid, but how do you stop just short of dissolving toomuch silica and end up with surfaces too rich in alkali?

There is an alternate method to elutriation. It is called screen separation. Three screens,

100 mesh, 200 mesh, and 325 mesh should be sufficient for most purposes. Enamel

classified through 100 mesh and remaining on 200 mesh is ideal for good transparents. That

which passed through the 200 and remained on 325 can be ground in a mortar and pestle to

pass through 325 and used for painting. Normally, opaque enamels can be used without

screening out the fines. In rare cases, it might be helpful to remove particles finer than 325

mesh.


12/22

Figure 2 shows a set of two screens along with a

collecting pan and a cover. Note a couple sizeable lumps of frit in the screen will aid in

keeping the wire cleared to speed up the process.

Figure 3 shows how the screens nest making the

operation easier. Of course, the enamel can be screened in single screens without nesting.

No doubt some enamelers will feel some extremely fine powder will adhere to the grain

surfaces throughout the screening and wish to remove it by washing. Alcohol is ideal for

washing enamel. It has high affinity for water and evaporates readily. Ethanol (ethyl or

grain) should be used, even though it is more expensive. Methanol (Methyl or wood) is

poisonous if taken internally or with prolonged breathing of the fumes.

Although we have pointed out water can be a source of problems with some enamels,others are quite resistant to water and little or no problem will develop. Our concern is the

teaching of washing as a fundamental principle. It should be taught as a special operation for

a special purpose, if taught at all.

If we were determined to use certain enamels and were concerned with obtaining

transparency, we would purchase it in lump form, and grind it in a mortar with a transparent

plastic cover with a hole in the center to allow the handle of the pestle to stick through. We

would grind a short time, screen, regrind, screen, continuing until enough enamel of the

proper mesh was obtained. We would wash, only if necessary, with water or alcohol. Any

left over enamel that had been exposed to water, should be discarded. Any ground enamel,

which has not been exposed to water, should be stored in a desiccator. Again, it is stressed,

all enamels do not require this degree of pampering.

Enamel being attacked by water is not a unique phenomenon. Water attacks all glass,

especially when freshly broken or ground into a powder. An enlightening experiment is toplace a piece of window glass in distilled water and ad a few drops of phenolphthalein. No

reaction will be indicated. Grind the piece of glass into a powder, add water and a few dropsof phenolphthalein. The solution will immediately turn pink, indicating the presence of alkali

in the solution.


13/22

Of historical interest, are the following two excerpts: The first from Cellini4, written1568: "We have a proverb in the craft which says, 'Smalto sottile e niello grosse.' 'Enamel

should be fine, niello should be coarse', and that's just what it is. You put your enamel in alittle round mortar of well-hardened steel, and about the size of your palm and then you

pound it up with very clean water and with a little steel pestle especially made for this

purpose of the necessary size. Some, to be sure, have pounded their enamels on porphyry or

serpentine stone, which are very hard and more over have done this dry, but I now think thatthe steel mortar is much better, because you can pound it so much cleaner."

The second excerpt is from the third edition (published in 1906) of Cunynghame, page 91:

"But, since this edition was published, Mr. Charles Tomes, F.R.S., has made some

interesting experiments which shed new light upon the subject." They will be found in the

August number, 1900, of the Journal of the Society ofArts. His conclusion is, "that the

apparent mud only consists of finer particles of the very same composition as the coarser

stuff, and that these fine particles, especially on the surface, become very quickly

agglutinated by the heat of the furnace, entangling between and beneath them an infinity of

small bubbles but that, when coarser particles are fired, they run together more slowly, and

then the air escapes for the most part, the little which remains forming large bubbles, whichdo not practically interfere with the transparency."

"The experiments of Mr. Tomes undoubtedly bear out the general proposition put forward

by him. He concludes that grinding enamels in paraffin oil* is not better than to grind them

in water." *(In the U.S., paraffin oil is called kerosene.)

"In this as a practical result, I am unable to agree with him, for although enamels kept

under water suffer but little change, enamels kept for many days in a state of fine, damp, mud

undoubtedly appear to undergo decomposition."

The observations of both Tomes and Cunynghame were correct. If Tomes applied the fine

enamel immediately after grinding, the small bubbles would have been the only

difference. And, had he applied the enamel thin, he might have eliminated most of the smallbubbles. Cunynghame was correct in that small particles deteriorate faster than large

particles. Small particles have more surface area in proportion to their volume than do largerparticles.

When working with transparent enamels, one of Cunynghame's remarks quoted earlier in

this article should be considered a fundamental principle: "So thin, however, are the layers

thus used, that they are fused up into transparent enamel."

We hope those who experiment using alcohol for washing will share their experience with

Glass on Metal Magazine


14/22

Paint is a term used to describe a number of substances that consist of a pigment

suspended in a liquid or paste vehicle such as oil or water. With a brush, a roller, or a

spraygun, paint is applied in a thin coat to various surfaces such as wood, me tal, or

stone. Although its primarypurpose is to protect the surface to which it is applied,

paint also provides decoration.

Samples of the first known paintings, made between 20,000 and 25,000 years ago,

survive in caves in France and Spain. Primitive paintings tended to depict humans

and animals, and diagrams have also been found. Earlyartists relied on easily

available natural substances to make paint, such as natural earth pigments, charcoal,

berryjuice, lard, blood, and milkweed sap. Later, the ancient Chinese, Egyptians,

Hebrews, Greeks, and Romans used more sophisticated materials to produce paintsfor limited decoration, such as painting walls. Oils were used as varnishes, and

pigments such as yellow and red ochres, chalk, arsenic sulfide yellow, and malachite

green were mixed with binders such as gum arabic, lime, egg albumen, and beeswax.

Paint was first used as a protective coating bythe Egyptians and Hebrews, who

applied pitches and balsams to the exposed wood of their ships. During the Middle

Ages, some inland wood also received protective coatings ofpaint, but due to the

scarcityofpaint, this practice was generallylimited to store fronts and signs. Around

the same time, artists began to boil resin with oil to obtain highlymiscible (mixable)

paints, and artists of the fifteenth centurywere the first to add drying oils to paint,

therebyhastening evaporation. Theyalso adopted a new solvent, linseed oil, which

remained the most commonlyused solvent until synthetics replaced it during the

twentieth century.

In Boston around 1700, Thomas Child built the earliest American paint mill, a

granite trough within which a 1.6 foot (.5 meter) granite ball rolled, grinding the

pigment. The first paint patent was issued for a product that impr oved whitewash, awater-slaked lime often used during the earlydays of the United States. In 1865 D. P.

Flinn obtained a patent for a water-based paint that also contained zinc oxide,

potassium hydroxide, resin, milk, and lin-seed oil. The first commercial paint mills

replaced Child's granite ball with a buhrstone wheel, but these mills continued the

practice of grinding onlypigment (individual customers would then blend it with a


15/22

vehicle at home). It wasn't until 1867 that manufacturers began mixing the vehicle

and the pigment for consumers.

The twentieth centuryhas seen the most changes in paint composition and

manufacture. Today, synthetic pigments and stabilizers are commonlyused to massproduce uniform batches ofpaint. New synthetic vehicles developed from polymers

such as polyurethane and styrene-butadene emerged during the 1940s. Alkyd resins

were synthesized, and theyhave dominated production since. Before 1930, pigment

was ground with stone mills, and these were later replaced bysteel balls. Today, sand

mills and high-speed dispersion mixers are used to grind easilydispersible pigments.

Perhaps the greatest paint-related advancement has been its proliferation. While

some wooden houses, stores, bridges, and signs

The first step in making paint involves mixing the pigment with resin, solvents, and additives

to form a paste. If the paint is to be for industrial use, it usuallyis then routed into a sand

mill, a large cylinder that agitates tinyparticles of sand or silica to grind the pigment

particles, making them smaller and dispersing them throughout the mixture. In contrast,

most commercial-use point is processed in a high-speed dispersion tank, in which a circular,


16/22

toothed blade attached to a rotating shaft agitates the mixture and blends the pigment into

the solvent.

were painted as earlyas the eighteenth century, it wasn't until recentlythat mass production

rendered a wide varietyofpaints universallyindispensable. Today, paints are used for

interior and exterior housepainting, boats, automobiles, planes, appliances, furniture, and

manyother places where protection and appeal are desired.

Raw Materials

Apaint is composed ofpigments, solvents, resins, and various additives. The

pigments give the paint color; solvents make it easier to apply; resins help it dry; and

additives serve as everything from fillers to antifungicidal agents. Hundreds of

different pigments, both natural and synthetic, exist. The basic white pigment istitanium dioxide, selected for its excellent concealing properties, and blackpigment

is commonlymade from carbon black. Other pigments used to make paint include

iron oxide and cadmium sulfide for reds, metallic salts for yellows and oranges, and

iron blue and chrome yellows for blues and greens.

Solvents are various low viscosity, volatile liquids. Theyinclude petroleum mineral

spirits and aromatic solvents such as benzol, alcohols, esters, ketones, and acetone.

The natural resins most commonlyused are lin-seed, coconut, and soybean oil, while

alkyds, acrylics, epoxies, and polyurethanes number among the most popular

synthetic resins. Additives serve manypurposes. Some, like calcium carbonate and

aluminum silicate, are simplyfillers that give the paint bodyand substance without

changing its properties. Other additives produce certain desired characteristics


17/22

Paint canning is a completelyautomated process. For the standard 8 pint paint can available

to consumers, emptycans are first rolled horizontallyonto labels, then set upright so that the

point can be pumped into them. One machine places lids onto the filled cans while a second

machine presses on the lids to seal the cons. From wire that is fed into it from coils, a

bailometer cuts and shapes the handles before hooking them into holes precut in the cans.

in paint, such as the thixotropic agents that give paint its smooth texture, driers, anti-settlingagents, anti-skinning agents, defoamers, and a host of others that enable paint to cover well

and last long.

Design

Paint is generallycustom-made to fit the needs of industrial customers. For example,

one might be especiallyinterested in a fast-drying paint, while another might desire a

paint that supplies good coverage over a long lifetime. Paint intended for the

consumer can also be custom-made. Paint manufacturers provide such a wide rangeof colors that it is impossible to keep large quantities of each on hand. To meet a

request for "aquamarine," "canaryyellow," or "maroon," the manufacturer will select

a base that is appropriate for the deepness of color required. (Pastel paint bases will

have high amounts of titanium dioxide, the white pigment, while darker tones will


18/22

have less.) Then, according to a predetermined formula, the manufacturer can

introduce various pigments from calibrated cylinders to obtain the proper color.

The Manufacturing

Process

Making the paste

y 1 Pigment manufacturers send bags of fine grain pigments to paint plants. There, the

pigment is premixed with resin (a wetting agent that assists in moistening the

pigment), one or more solvents, and additives to form a paste.

Dispersing the pigment

y 2 The paste mixture for most industrial and some consumer paints is now routed into

a sand mill, a large cylinder that agitates tinyparticles of sand or silica to grind the

pigment particles, making them smaller and dispersing them throughout the mixture.

The mixture is then filtered to remove the sand particles.

y 3 Instead of being processed in sand mills, up to 90 percent of the water-based latex

paints designed for use byindividual homeowners are instead processed in a high-

speed dispersion tank. There, the premixedpaste is subjected to high-speed agitation

bya circular, toothed blade attached to a rotating shaft. Thisprocess blends the

pigment into the solvent.

Thinning the paste

y 4 Whether created bya sand mill or a dispersion tank, the paste must now be thinned

to produce the final product. Transferred to large kettles, it is agitated with the

proper amount of solvent for the type ofpaint desired.

Canning the paint

y 5 The finished paint product is then pumped into the canning room. For the standard

8 pint (3.78 liter) paint can available to consumers, emptycans are first rolled

horizontallyonto labels, then set upright so that the paint can be pumped into them.

A machine places lids onto the filled cans, and a second machine presses on the lids

to seal them. From wire that is fed into it from coils, a bailometer cuts and shapes the


19/22

handles before hooking them into holes precut in the cans. A certain number of cans

(usuallyfour) are then boxed and stacked before being sent to the warehouse.

Quality Control

Paint manufacturers utilize an extensive arrayof qualitycontrol measures. The

ingredients and the manufacturing process undergo stringent tests, and the finished

product is checked to insure that it is of high quality. A finished paint is inspected for

its density, fineness of grind, dispersion, and viscosity. Paint is then applied to a

surface and studied for bleed resistance, rate of drying, and texture.

In terms of the paint's aesthetic components, color is checked byan experienced

observer and byspectral analysis to see if it matches a standard desired color.

Resistance of the color to fading caused bythe elements is determined byexposing aportion of a painted surface to an arc light and comparing the amount of fading to a

painted surface that was not so exposed. The paint's hiding power is measured by

painting it over a black surface and a white surface. The ratio of coverage on the

black surface to coverage on the white surface is then determined, with .98 being

high-qualitypaint. Gloss is measured bydetermining the amount of reflected light

given off a painted surface.

Tests to measure the paint's more functional qualities include one for mar resistance,

which entails scratching or abrading a dried coat ofpaint. Adhesion is tested by

making a crosshatch, calibrated to .07 inch (2 millimeters), on a dried paint surface.

Apiece of tape is applied to the crosshatch, then pulled off; good paint will remain on

the surface. Scrubbabilityis tested bya machine that rubs a soapybrush over the

paint's surface. A system also exists to rate settling. An excellent paint can sit for six

months with no settling and rate a ten. Poor paint, however, will settle into an

immiscible lump ofpigment on the bottom of the can and rate a zero. Weathering is

tested byexposing the paint to outdoor conditions. Artificial weathering exposes a

painted surface to sun, water, extreme temperature, humidity, or sulfuric gases. Fireretardancyis checked byburning the paint and determining its weight loss. If the

amount lost is more than 10 percent, the paint is not considered fire-resistant.

Byproducts/Waste


20/22

A recent regulation (California Rule 66) concerning the emission of volatile organic

compounds (VOCs) affects the paint industry, especiallymanufacturers of industrial

oil-based paints. It is estimated that all coatings, including stains and varnishes, ar e

responsible for 1.8 percent of the 2.3 million metric tons of VOCs released per year.

The new regulation permits each liter ofpaint to contain no more than 250 grams

(8.75 ounces) of solvent. Paint manufacturers can replace the solvents with pigment,

fillers, or other solids inherent to the basic paint formula. This method produces

thicker paints that are harder to apply, and it is not yet known if such paints are long

lasting. Other solutions include using paint powder coatings that use no solvents,

applying paint in closed systems from which VOCs can be retrieved, using water as a

solvent, or using acrylics that dryunder ultraviolet light or heat. A consumer with

some unused paint on hand can return it to the point ofpurchase for proper

treatment.

A large paint manufacturer will have an in-house wastewater treatment facilitythat

treats all liquids generated on-site, even storm water run-off. The facilityis

monitored 24 hours a day, and the Environmental Protection Agency(EPA) does a

periodic records and systems check of all paint facilities. The liquid portion of the

waste is treated on-site to the standards of the local publiclyowned wastewater

treatment facility; it can be used to make low-qualitypaint. Latex sludge can be

retrieved and used as fillers in other industrial products. Waste solvents can be

recovered and used as fuels for other industries. A clean paint container can be

reused or sent to the local landfil

Read more: Howpaint is made - manufacture, making, used, components, composition,

product, industry, machine, Raw Materials, Design, The Manufacturing Process ofpaint,

QualityControlhttp://www.madehow.com/Volume-1/Paint.html#ixzz1FuX3aV37

Paints - Key InputsyThe paint industry is raw material intensive. Paint involves the mixing of various

raw materials in various proportions. The raw materials are of a wide variety.On an average, raw materials account for 60% of net sales (industry average).In case of small-scale units it forms up to 70% of the net sales.

yHigh cost and erratic availability of raw materials mark the Indian paint industry.


21/22

Around 300-400 raw materials are required to manufacture different kinds ofpaints. The high number of raw materials and finished goods highlights thworking capital intensity of the sector.

yMost of the raw materials are petroleum based. Thus paint companies benefitwhen the petrochemical industry goes into its cyclical downswing. A hike in theprice of petroleum products raises input costs negating the impact of a cut in

import tariffs on raw materials.

yRaw materials frequently run into short supply, resulting in high inventory cost.The shortage of one specific material could result in severe manufacturingproblems It is estimated that 18-20% of the total raw materials used theindustry are imported.

yMost paint companies are hit by the fact that they do not make the rawmaterials themselves. For example, phthalic anhydride (PAN) is manufacturedfrom orthoxylene and which goes into the production of paints along wittitanium dioxide. Asian Paints is the only paint company that manufacturesPAN. The other paint companies have to import their stock. Since PAN pricesgenerally outpace international orthoxylene prices by almost 50% paint

companies end up paying a fortune when prices rise. In such a situation AsianPaints benefits by selling PAN in the open market.

yRaw materials are divided into three major groups, namely, pigments (titaniumdioxide, zinc oxide etc.), solvents (mineral turpentine) and resins andadditives.

yPigments are finely ground solids of different shades to give colour, durability,consistency and other properties to paint. It is also one of the major ramaterials, accounting for one-third of the total raw materials cost.

yAmongst the vital pigments used in the process of paint manufacture isTitanium dioxide (TiO2) and the industry consumes around 60% of TiO2. Thispigment is available in two grades: anatase and rutile, of which anatase iexclusively used in interiors while rutile is preferred in exteriors. India hasabundant raw materials for the manufacture of TiO2, especially ilmenite ofwhich it has 12% of the worlds deposits. It is ironical that the paint industrypresently imports TiO2 in excess ofRs.1 bn - a figure that may touch Rs 2 bnby the turn of the century. TiO2 is responsible for the demand-supply gap. If thestrong demand growth boosts domestic production of TiO2, there will be anincreased usage in various sectors. If the raw materials are properly utilized,India has the potential to emerge as a net exporter of TiO2 in the next fivyears.

ySolvents are volatile organic compounds (VOC) used to dissolve, suspend orchange the physical properties of other materials. They are generally used tbring down the viscosity of paints to the desired level, which also reduces the

cost of paint formation. They constitute 70%-75

% of the paint liquid andultimate escapes into the atmosphere when the fluid dries. Solvents such asethylene glycols and alcohols are finding wider use as co-solvents in newwater-borne formulations.

yBinders are generally oils, resins and plasticisers that give paints its protectiveproperty. Most resin manufacturers make alkyds, polyesters, emulsionpolymers, epoxy resins, amino resins, powder coating resins etc.

yAdditives are added in small proportion to the paint to improve its performance


22/22

characteristics in various ways. Skinning inhibitors, fungicides, wetting agents,driers are included in this category

enamel paqint

Documents