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Additives

Everybody needs a little help once in a while. Some days everything seems to work out just fine and other days a little something extra is all one needs to get the job done. For old folks it might be a dietary supplement that puts them right. For house paints, there is a world of additives to help give a little extra something to make things feel right. O-Gee has recently placed a number of new additives in stock since getting access to Coronado’s and Insl-x’s paint line. These products are used to adjust the working properties or to add a special feature to a coating. Working properties include characteristic features such as dry times, viscosity, and surface tolerance. Special features include texture, mildew resistance and insect control.

For modifying dry times you’ll find specialized items for both slowing down and speeding up a coating’s time to harden. Lacquers dry so quickly that the rapid evaporation of their solvents often drops the temperature of the surface below the dewpoint. As condensation develops the surface turns white and dull resulting in a condition known as blushing. The answer is to slow the evaporation of solvents with Lacquer Retarder.

Likewise, oil-base and alkyd products sometimes dry too fast and need to be slowed down to improve their flow and leveling. Although adding thinner might help to some extent, Penetrol from the Flood Company gives excellent brushing properties without sacrificing viscosity.

Water base paints can also be slowed to improve their brush out. Coronado’s Latex Retarder is a thin blend of special solvents that, unlike water, works on the emulsified droplets of paint to remain soft until they coalescence into a paint film. Floetrol from Flood also helps eliminate brush strokes but its heavier viscosity makes it less suitable for spraying than the Latex Retarder.

Speeding up drying times can be just as important, especially when downtime is an issue. Lacquers and water-base coatings don’t really need to speed up as they dry to the touch so fast anyway, alkyds on the other hand can be a real problem. Traditionally, japan drier is added to speed the uptake of oxygen into the paint for more rapid curing. Lately there is another player on the scene to help oil-base paints dry faster. Insl-x has a product called Alkyd Accelerator that assists in getting an alkyd to harden in a much shorter period. Benjamin Moore’s Urethane Gloss and Hardness Enhancer #76-85 is formulated for their Industrial M20 Rapid Dry Gloss Enamel. (It has, however, proved to work in other oil base paints with good results.) It is important to not over do these products as they can make paint harden in the can.

Set times of many industrial coatings can also be adjusted. Thermoset coatings can be adjusted with temperature. Simply simply putting the mixed material in a cooler of ice can attain longer pot life. On the other hand, since epoxies set slower in cold conditions, accelerators are often used when they are applied during winter months. The same accelerators can be used in warmer temperatures to speed setting for less downtime.

Another working property that can use some adjustment is surface tolerance. This means that a coating is less affected by a defect of the surface or preparation. The best example is in the world of lacquers. Contaminants present on a surface cause an effect known as fish eye. Coronado’s Smooth All added to a lacquer coating will eliminate this defect and allow the coating to flow smoothly over the surface. It works by lowering the surface tension of the coating along with special solvents to increase compatibility with contaminants. In car paints, a silicone modifier is used to eliminate fish eye. Flood’s Easy Mix E-B added to a latex paint will give it some ability to penetrate into porous and chalky surfaces. This is accomplished with emulsified alkyd resins – much like Benjamin Moore’s alkyd modified house paints. Easy Mix E-B also includes wetting agents to better soak into a chalky or porous surface. Adding thinner to paint will, of course, allow it to soak into a surface but it may take the binder with it leaving a weakened film on top. Adding Easy Mix E-B gives latex paint additional resins to soak in while minimizing binder loss.

Additives used to add the special features of texture begin with Bondex’s Roll-A-Tex line of graded perlite for simulating sprayed stucco. Any of the three different grades of fine, medium or coarse are added directly to liquid paint to produce decorative effects or help obscure surface defects. Skid resistant materials, such as Bondex’s Skid-Tex and Benjamin Moore’s Anti-Slip Aggregate M67, are spread into wet floor coatings then back rolled to help prevent slipping accidents.

On a microscopic scale, Coronado’s Flattening Paste is adds a super fine texture to lacquer finishes that changes their sheen level. Depending on the amount added, you can vary from a gloss to satin or flat and anything in between.

An additive to control insects or mildew growth is a special feature that works by dispersing a poison throughout the paint film. Because of their toxicity they are limited to exterior use only. Insect control is desirable in covered carports and garages where spiders enjoy setting their webs. Other insects that dwell on the faces of buildings will also be eliminated. Mildewcides work with great effect but any area that stays constantly damp, a dripping air conditioner unit for instance, will overcome its abilities to hold back organic growth.

Additives can change the working properties of a coating or to add a special feature by simply stirring it into the product. Some are simple dispersants while others may react with the chemicals that constitute the paint film. Since all of these alter the formulation, manufacturer defect warranties may be compromised and care must be taken on the part of the consumer to ensure that the additive and the paint can be used together. A paint manufacturer like Coronado that supplies additives will have tested their products for compatibility. Other generically similar products may work well with a particular additive, but not necessarily. Testing is recommended prior to full scale use to determine if there are any negative effects. Unusual aromas, increased brittleness, a change in opacity, decreased spread rates, induced pot life, and difficult brushing are all possible side effects from use of certain additives. Over adding may also create its own share of problems.

A variety of additives should be a part of every painter’s tool box. Paints are made and tested in a controlled laboratory setting but are applied in the real world where environmental conditions change day to day. The label might say that paint X is good for both metal and wood, however, the same paint applied on a metal door during a windy hot dry day will seem like an entirely different product on the wood trim in a damp, cool restaurant. The use of the appropriate additives will help even out the differences and provide the right working properties for the working conditions.

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