Diffrent type of additives in paint

Below is a list of additives used in the manufacture of latex paints, and a description of how they affect the properties of those paints.

1. Thickeners and Rheology Modifiers
(rheology is the science of how a liquid tends to flow)

• provide adequate viscosity (thickness), so the paint may be applied properly
• impact how thick the paint goes on and how well it flows out when applied
• modern rheology modifiers help latex paints
- resist spattering when applied by roller
- flow out smoothly
- be less likely to spoil than with older generation thickeners
(with spoilage, the paint may smell putrid and/or lose viscosity)

2. Surfactants (specialized soaps)

• stabilize the paint so that it will not separate or become too thick to use
• keep pigments dispersed for maximum gloss and hiding
• help "wet" the surface being painted, so the paint won't "crawl" (move about)
when it is applied
• provide compatibility with tinting colorants so that the correct color will be obtained
and help assure that it won't change before the paint is used

3. Biocides: two types are used in latex paints

1. a preservative to keep bacteria from growing in the paint

(This is especially important for paint stored in containers that are repeatedly opened and closed, because contamination can occur.)

2. a mildewcide, to discourage mildew from growing on the surface of the paint after it has been applied.

(This is used mainly in exterior products, although some interior paints, such as those formulated for use in damp areas, e.g., kitchens and baths, may also contain mildewcide.)

4. Defoamers break bubbles as they are formed in the paint when:

• the paint is mixed in the factory
• it is put on the shaker or stirred
• it is applied to the surface (especially important when rolling the paint on)

5. Co-solvents are additional liquids other than water; that:

• aid the binder in forming a good film when applied down to the minimum recommended application temperature
• help the liquid paint resist damage if frozen
• enhance brushing properties, including flow and "open time" (the time the paint can be applied and worked, before it sets up)

The co-solvents are generally volatile organic compounds (VOCs).

(Via PQI)

When painting, watch the temperature

As the days grow shorter and the nights grow cooler, you may suddenly realize that you only have a few weeks left to finish your exterior painting projects. However, beware of painting outdoors when the weather turns nippy. Painting when the weather is too cold is a mistake that will leave you with unsightly consequences.

Most manufacturers instruct homeowners to apply solvent-based paint when ambient and surface temperatures are above 45 degrees F and latex paints when ambient and surface temperatures are at least 50 degrees.

Solvent-based paints thicken in lower temperatures, causing stiffer brushing, heavier application and slower drying. This can mean paint runs, sags and wrinkling on vertical surfaces, plus an overall reduced rate of coverage per gallon.

Below 50 degrees, latex paints dry more slowly, especially when high humidity is present. This hinders coalescence, which can lead to poor film-forming, lack of surface adhesion and premature paint failure.

Some manufacturers offer latex paints that can be applied at temperatures as low as 36 degrees F. These specially formulated products contain coalescing agents that aid in film-forming during lower temperatures. Check with your local independent paint retailer for information about these products.

Another thing to consider about seasonal painting is the amount of daylight. When the days are short, there is less daylight available to aid in drying. If you're using a solvent-based paint, which dries by oxidation, daylight is especially critical. So, be sure to paint early in the day so that light is present to add in the drying process.

Also consider the effect of heavy dew. Humidity affects the drying time of all paints, but especially latexes. Most manufacturers recommend that at least two hours be allowed for paint to dry before sunset if cool temperatures and heavy dew are expected that evening.

Finally, keep in mind that cooler temperatures may extend the time before the paint reaches serviceability or hardness. An enameled door requires more time before it can be closed without sticking to the jamb. A clear coating applied to a deck will need more time before you can walk on it. Primers require more time before top-coating. Knowing all of this may aid you as you go about your painting chores in the spring or in the fall.

When in doubt, remember to call your local paint and decorating retailer for advice and assistance. Or contact Snowcem Paints.

(via PDRA.)

Types of paints to choose from

There are different kinds of paints for different jobs. Not all kinds of paint are good on all surfaces. You should make sure that you use the right kind of paint when you are designing your room. If you use the wrong paint on a certain surface, you may have more of a mess than you intended. Check out what kind of paint you should use before you buy it. This will save you money and time in the long run.

There are primers and sealers that you should buy to prepare the surface for the actual paint color. Primers are used to prepare bare or previously painted walls. Sealers are mostly used for bare woods. If you are painting a room that will have kids using it, you should go for a latex paint because it can be cleaned up with soap and water.

There are special paints that are becoming more and more popular with stores. Usually water based paints are different by the additives or the application technique. There is a magnetic paint that contains iron dust mixed with a primer. This type of paint is best for textured finishes for outdoor purposes.

Another type of paint is milk paint. It is a natural and non-toxic paint made from mild protein and earth pigments. It works best for bare wood. Topcoats can be either water or solvent-based coatings. Topcoat finishes create a durable finish on wood floors, furniture, and doors.

There are different finishes for paint also. Flat has no sheen and it is best on walls in rooms that have little use. It will conceal some minor imperfections and is washable but not scrubbable. Eggshell has a smooth finish with a subtle sheen. It is good for walls in family rooms and bedrooms. It is also washable. There is also satin finish, which is a step up from eggshell. It is an all-purpose and popular sheen suitable for almost any room in the house.

Semi gloss is a medium sheen that is good for walls and trim in high abuse areas of the house like the kitchen, bathroom and children’s rooms. It is very durable and washable. Gloss is a paint that is best for doors, trim, and cabinets.

When you are painting, there are a few tips that you should use. When painting walls and trim, use a lower sheen on the walls and higher sheen on the trim. Do not use latex over oil. Latex has a faster drying time so that you can use the room faster. Sometimes when we are painting in our home, we need it to dry fast so that we can put the items back in to that room for use.

When you are painting a room, make sure that you paint the ceiling first. You want to do this so that you do not mark up the walls after they have been painted. This will only cause you more work in the end. When you paint the ceilings, it is best to use a longer pole. This will help you get it done faster and you will not have to worry about getting up and down off of ladders so that you can reach all the areas of the room.

(via Ezilon.com)

How to paint the exterior of your house

Step One

Repair or replace any damaged surfaces, whether wood, stucco, masonry or metal.

Step Two

Wash off all surfaces. Use a high-pressure water sprayer (available to rent) to reduce labor. Make sure that surfaces dry thoroughly.

Step Three

Use sandpaper or a paint scraper to remove any loose, cracked, chipping or blistered paint - down to raw surfaces if necessary. Use a small drop cloth as you go to catch loose bits of paint and debris. If you decide the exterior needs to be sandblasted, hire a licensed professional.

Step Four

Patch all nail or screw holes, gouges and cracks.

Step Five

Caulk such places as seams and corners, above door and window trim, and where trim meets siding - or where any material meets a different kind of material, such as trim over masonry. (Exception: Don't use caulk where siding or shingles overlap or between shingles.) Use high-grade exterior caulk. Better caulks (such as silicone) actually bond to surfaces like glue and resist breaking down.

Step Six

Use epoxy filler (the material used for car bodies) to repair serious problems in woodwork.

Step Seven

Cover dark stains - a wood knot, old paint, wood stain - with a stain-blocking primer. The same goes for mildewed areas; you can find primers and additives made especially for mildew.

Step Eight

Sand all rough or glossy surfaces; paint needs a slightly roughened surface to stick to. You can also use paint deglosser on all glossy surfaces. Remove sanding dust and debris.

Step Nine

Remove or cover all light fixtures, plumbing outlets, electrical covers and house numbers.

Step Ten

Remove all screens. You don't want to get paint on them; it's difficult (or impossible) to remove.

Step Eleven

Use drop cloths to cover everything you don't want to paint, such as plants, walkways, cars and your neighbors' property.

Step Twelve

Apply primer over all raw surfaces. Note that different surfaces - paint, metal, wood, stucco - require different primers.

Step Thirteen

Allow the primer to dry, then apply at least two coats of exterior paint. Let each coat dry between applications according to the manufacturer's instructions. Use a brush on all woodwork and a paint roller or spray machine for everything else.

• You can't paint vinyl or plastic. If there's a problem with any of these surfaces, you'll probably have to replace them.
• If the exterior was painted before the 1980s, you may be dealing with lead-based paint, which is extremely hazardous, especially for kids and pregnant women. Call the National Safety Council's Lead Information Center at (800) LEADFYI for instructions on how to deal with it safely.
• If you're using anything other than water-based latex, never put paint-soaked or cleaner-soaked tools or rags in an enclosed area of any kind - even a trash can with a lid. This is a recipe for spontaneous combustion.

(via ehow)

Can you paint over an oil-based paint with latex paint or is it vice versa?

The rule of thumb is that, given proper surface preparation, for exterior use you can apply quality latex paints over oil-based, but not the reverse. However, if you have many layers of oil based paint, stick to using oil on oil.
For interior use, generally you can use one over the other. Some manufacturers of latex products will recommend a primer when going over oil-based paint.

When is the best time to apply latex house paint?

Many times the question arises, "When is the best time to apply latex house paint?" Most paint can labels will say, "Above 50° F." and that's the only limitation. This is really an oversimplification -- however, can you imagine the effect if a paint label read:

"Apply only on properly prepared surface. Conditions should be 60° F. to 85° F., 40% to 60% relative humidity during the time of application and for a period of two weeks thereafter."

The above statement is outrageous, but it does outline ideal painting conditions. To insure a long life house paint job with latex requires common sense and a little cooperation from Mother Nature.

Basic Guidelines.

Time of Year: Late Spring or early Fall will afford the best results. Temperatures are mild. One has to watch the threat of rain or high evening humidity. Summer is also a good time to paint, but one should avoid painting when the thermometer goes over the 90° mark.

If at all possible, never use latex during "Indian Summer." Those days in the late fall are the worst time to paint. Any freeze-thaw cycles subjected to a latex paint film during its first two weeks of cure can conceivably shorten the life of the paint job.

In short, the latex house painting season starts after the last frost in the Spring and runs until about two weeks prior to the first expected frost in the Fall.

Time of Day: An early morning start never hurts, but a late finish and you are asking for trouble. Generally one should stop painting a couple of hours before sunset, especially during those days of spring and fall that are cool and humid. Glycol bleeding can result if conditions are just right.

Also, during the day, never paint in direct sunlight. Work opposite the sun.

Temperature/Humidity: Temperatures in the seventies are ideal. Above 85° F. latex tends to dry too quickly and may not properly wet out the surface. When temperatures drop below 60° F. latex curing is retarded, and below 40° F. coalescence is severely hampered. One should not paint if the temperatures may drop to 40° F., even 24 hours after application.

When humidity reaches above 70% the evaporation of water from the latex paint film is suppressed. Avoid painting on those days when humidity is excessively high.

Surface Preparation/Application: Surface preparation is critical when using latex paint. Surface must be free of dirt, mildew and chalk. Apply with a quality applicator to a dry film thickness of 3-4 mils.

Final Thought: One might think they would be better off using oil based paint. WRONG! Using good-painting practices, a latex paint job without a doubt will provide superior durability over an oil based finish.

Should you use oil or latex paints?

Latex paint is a great choice for most instances, but there are still situations where a solvent-based paint may be preferable. To help decide which is best in your case, consider the following:

What are the advantages of latex paints?

• They have a less objectionable odor, which makes them good for repaints and painting in occupied areas, where solvent odor is an issue.
• They clean up with soap and water; there's no need to work with hazardous and/or flammable solvents, and no used solvent to dispose of afterwards.
• Latex paints dry faster, and can be recoated sooner; this makes them a good choice for painting in occupied areas, where someone might touch or brush up against the freshly painted surface.
• Latex paint binders hold up better in sun-exposed areas, because they're more resistant to UV (ultraviolet) radiation; alkyd and oil binders will absorb more of this radiation and break down more quickly.
• Latex paint films are less prone to yellowing over time, especially with white, light off-white and pastel colors.
• Latex paint films are more breathable; they allow small amounts of water vapor to pass through the film, so the chance of blistering is reduced. This is especially important when the surface being painted is slightly damp.
• Latex paint films have better gloss and color retention, so they'll keep a 'like-new' appearance longer.
• Latex paint films are more elastic, so they can expand and contract with the substrate better; this means they'll be less likely to crack and peel over time.

What are the advantages of solvent-based paints?

• Solvent-based paints are less sensitive to application conditions, which means they can be applied over a wider temperature and humidity range (however, the surface must still be dry for good adhesion).
• Solvent-based paints can be applied in a thicker coat with less sagging, for better coverage.
• Solvent-based paints have better flow and leveling characteristics, so they'll dry to a smoother finish, with fewer brush or roller marks (this advantage is reduced somewhat for low V.O.C. alkyd paints).
• Solvent-based paints provide better surface penetration, especially on weathered wood; this means improved adhesion and better surface protection.
• Solvent-based paints have better adhesion on smooth surfaces.
• Solvent-based paints initially have a sharper, richer-looking gloss (however, they also tend to lose their gloss faster over time).
• Solvent-based paints initially provide a harder, more durable finish (however, they also tend to become more brittle over time).