Waxes and paint sealants: what’s the difference?
Despite their widespread use, considerable confusion exists over what waxes and sealants actually do, what they don’t do and whether there’s any difference between them.
Historically, the term “wax” was used to describe final finish products that contained natural waxes such as carnauba, while the term “paint sealant” was used for final finish products containing synthetic polymers such as silicone. Waxes tended to generate more shine, while paint sealants tended to last longer.
Today, however, the distinction between these products is not as pronounced. Many “waxes” contain synthetic polymers, while many “paint sealants” contain natural wax. It’s best to review the product label to determine its gloss level and durability.
What do waxes & paint sealants do?
As the name “final finish” suggests, waxes and sealants are applied to the paint after it has been cleaned and restored, as the final step in the reconditioning process. They perform two basic functions:
- Protect the painted surface
- Enhance its gloss
Waxes and sealants contain resins which bond to the paint forming a protective barrier. These resins include the natural waxes (carnauba) and synthetic polymers (silicone) mentioned earlier, along with mineral seal oil and glycerin, among others. The barrier created protects the paint by:
- Diffusing ultra-violet radiation (which causes oxidation)
- Preventing airborne contaminants from reaching paint
- Lowering surface temperatures
- Improving mar resistance
Oxidation is the dulling of the painted surface that occurs when the sun’s ultra-violet rays break the molecular bond created when the clearcoat initially cures. Once this bond is broken, oxygen penetrates the clearcoat and depletes the paint’s natural oils and resins, resulting in a dull, chalky finish.
The barrier formed by waxes and sealants diffuses these harmful UV rays, minimizing their impact on the clearcoat. While oxidation can’t be completely prevented, the process can be slowed considerably, especially if the protective barrier is maintained through periodic re-application of the wax or sealant.
The barrier also prevents bird droppings, road salt, tree sap and other contaminants from coming into direct contact with the paint, which can etch or stain the surface. High surface temperatures accelerate this etching and staining, and waxes and sealants help to lower these temperatures.
Waxes and sealants also minimize the marring that can result from the paint’s inevitable brushes with bumpers, curbs, trash cans, etc.
The durability of the protective barrier depends on the strength of the bond between the resins and the painted surface. This will vary depending on the number and type of resins present and the condition of the surface as the wax or sealant was applied. Chemically-bonding silicones can last up to six months, while physically-bonding silicones, mineral seal oils, glycerin and natural or synthetic waxes last one to four months.
Climate affects the durability of waxes and paint sealants, as well. Harsh weather conditions such as rain, wind, snow will break the bond between the resin and the painted surface much more quickly than will dry, mild conditions. Constant exposure to bright sunlight will also accelerate wax and sealant deterioration (yes, the UV rays against which the wax protects the clearcoat will break down the wax, as well).
Waxes and sealants enhance gloss in two ways. They fill in any indentations that were too deep to abrade out, which levels the painted surface. The newly level surface reflects light in a uniform manner which intensifies its shine.
This is not to suggest that waxes and sealants will restore gloss to heavily scratched or oxidized surfaces. While they can fill light scratches, they will not “level” a heavily scratched surface enough to produce uniform light reflection. Oxidized surfaces absorb instead of reflect light, so any oxidation must be removed if the gloss is to be restored.
The specific resins a wax or sealant contains also contributes to the gloss level each product will generate. Every resin has a unique “refractive index” (degree to which it reflects light). Logically, those products containing resins with high refractive indexes tend to produce glossier finishes. In general, durable resins tend to be less refractive.
What won’t waxes & paint sealants do?
As discussed earlier, waxes and paint sealants are “final finish” products that are applied after the paint is cleaned and restored. They do not clean or restore the paint!!
Car soaps, body prep solvents and clay bars are used to remove dirt, grease, tar and road film and other surface contaminants that commonly afflict the paint. These products should be used, and contaminants removed long before a wax or sealant is ever applied.
When it comes to heavy scratches and oxidation, waxes and paint sealants are not the answer either. These imperfections must be removed from the painted surface with products and equipment designed for this purpose: a buffing compound and high speed buffer. Compounds contain abrasives which cut away the oxidized paint layer and reduce the depth of scratches by abrading away their “ridges”.
If light scratches and oxidation are present, buffing with a mildly abrasive polish is recommended. A polish is a lotion containing mild abrasives and resins that can be applied with a buffer or by hand. The abrasives remove scratches and oxidation by abrading away their “ridges” in a manner similar to compounding, but with much less paint being removed.
Granted, there are waxes containing light abrasives which are sold as “cleaner” waxes. If the “cleaning” you require is the removal of surface imperfections, these waxes will not work. They simply do not generate the level of abrasion necessary to remove scratches and oxidation.
What are the “do’s & don’ts” when applying waxes & paint sealants?
The recommended procedure for applying a wax or paint sealant: is:
- Ensure the painted surface is clean, out of direct sunlight and cool to the touch.
- Shake the container before and during use.
- Start with the roof, and proceed to the hood, trunk and sides.
- Apply product lightly and evenly using an orbital buffer or pre-moistened applicator pad.
- Allow product to dry to a haze.
- Remove product with a clean, soft polishing towel.
It is critical to ensure that the paint is free of dirt, tar, grease, and other surface contaminants before applying your final finish product. Neither wax nor paint sealant will adhere properly to a dirty surface.
Applying wax or sealant in direct sunlight or to a hot surface will accelerate its solvent evaporation which can cause uneven drying and difficulty in residue removal.
It is important to shake lotion and, especially, liquid waxes thoroughly before application. The solvents in these products can separate from the resins, which will prevent proper adhesion if not corrected.
One of the most common waxing mistakes is the application too much product. Ninety eight percent of the wax or sealant applied to the paint is wiped away as residue once the product dries. Only the small fraction of the wax in direct contact with the surface actually bonds to the paint. So you need only apply an extremely thin layer initially.
Yes, this means that those of you applying coat after coat of wax are wasting both time and product. All the wax or sealant applied after the initial bonding takes place is coming off in your towel as you remove the residue.
When washing a freshly-waxed surface, be sure to use a pH neutral car soap instead of a highly alkaline dish soap or household cleaner. The alkalis will strip the resins from the painted surface, lessening gloss and exposing the surface to the elements.
Finally, you should not apply a wax or paint sealant to freshly applied paint. A clearcoat takes 60 to 90 days to “cure” (have its solvents evaporate fully). If a clearcoat is sealed before it has cured completely, its solvents can’t escape as they rise to the surface. This results in small pin-hole surface imperfections called “solvent pop” that are very unsightly.