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Shiny & Dry - Understanding Sealants and Drying Agents |
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By Rick Martens, CSI
Two important products at the end of your wash process can give you and your customers exactly what you want: Shiny vehicles coming out of the car wash. In this article I'll tell you about those products, drying agents and sealants, and give you some tips on how to maximize their potential to deliver shiny, dry cars.
An Overview of Drying Agents
The objective of a Drying Agent is to remove water from the surfaces. This is accomplished by making the surfaces of the vehicle very "Hydrophobic" or water hating (literally "water fearing"). After the application of a Drying Agent, water on the surface will exhibit increased surface tension and form into beads and puddles that will do their best to roll off of the surface by gravity. The action of the blower will help move these puddles and beads, especially on the horizontal surfaces such as roofs, hoods, and trunk lids.
The chemistry involved in making these surfaces hydrophobic is to use a water emulsion involving a very hydrophobic material and a cationic surfactant. The cationic surfactant is a material that has two functions, one is to hold the hydrophobic material into water while in the drum of product, secondly to attach it to the surface of the vehicle when diluted and applied.
An Overview of Sealants
Sealants also remove water from the cars but they also provide extra benefits such as improved shine, ultraviolet light protection, and higher performance in all application equipment. Shine is a result of a surface being made so smooth that reflected light is not scattered but performs more like a mirror (that is why a wet car looks shiny). Protection from ultraviolet light is important as the sun will oxidize the finish of a vehicle over time and make the paint look flat and unattractive.
The chemistry of sealants is similar in theory to the drying agents, but they may differ greatly in the actual ingredients and they generally contain more ingredients to provide the added benefits.
Start With A Clean Car
To achieve a good result from your sealant and drying agent applications you must have a clean vehicle. If you apply these products to a car that is still dirty, you can expect poor results. Dirt left on the surface will contain a variety of materials which can inhibit the attachment of the cationic surfactant and hydrophobic portion of the product. The result is a wet car with a surface that when dry, will be very uneven and lack shine.
Drying Agent Application
When applying a drying agent, you inject the emulsion into a stream of water, often at very low levels. When the water hits the vehicle surface the emulsion must break and the active ingredients attach to the surface. The best, most efficient way to achieve good results is to apply the drying agent with as little water volume and pressure as practical. The greater the volumes and pressures, the less the mixture will come in contact with the surface, and active ingredients will go onto the floor, not the car. It really takes very little drying agent to coat the entire surface, but if it is flushed on with too much water a lot will be wasted.
Set Rinse Magic
Ever wonder why adding more water to the surface actually helps get water off the surface? The secret lies in the breaking of the emulsion that I mentioned above. The products are formulated to stay emulsified in the water in the drum, but that must change on the vehicle. Frequently the emulsion holds a little too tightly even when diluted during application. The dispersed emulsion is covering the car but not separating as desired. Once the pure set rinse water is applied, the emulsion stability is disturbed, the actives separate from the water and attach to the surface. The surface is then hydrophobic and away goes the water.
Sealants Add Value
A good sealant should give you good drying. It starts with a hydrophobic material emulsified in water with a cationic surfactant just as with a drying agent, but the actual materials can vary greatly. As with a drying agent, a sealant will perform best when applied under low pressure and low volume, but we must demand more. Frequently these products need to be applied at higher pressure and volumes in order to rinse off a foaming polish or conditioner. Thus we must have a product that is more efficient than the standard drying agent formula and give good water beading even when applied under high pressure.
As well as good water beading performance in the wash, the product should provide extra value to the customer. A good shine from a smooth coating of the surface, and ingredients that help reflect the maximum amount of light provide assurance to the customer of that extra value. In addition to what they do see, ultraviolet light absorbers can be added to protect the surface so they don't see oxidation any sooner than they should. Your car wash should utilize the manufacturers handouts to help market these products to the customer and to help explain their benefits.
No Spot Finish
When a car leaves the blower, small beads of water may still be left on the surface. The amount of water can be influenced by, the condition of the finish, the shape of the vehicle, and the effectiveness of the sealant or drying agent application. Regardless of the reason, the quality of the water in those small beads will determine if you will see a spot there when the water dries. These spots are caused by dissolved minerals in the water, and the best insurance against spots is to use spot-free water as the final application. Applying too much sealant or drying agent could also cause spotting, but it would have to be an extreme overdose to have that effect.
If you follow directions on your drying agent and sealant products labels, make sure the vehicle is clean and well rinsed and finish with spot free water you should be able to achieve the kind of shiny, dry results that will satisfy you and your customers.
(ICA update, Jan 2001)
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