Underbody Coating
Objective: The main aim of this challenge is to understand the role and necessity of underbody coating for a vehicle.
UNDERBODY COATING:
Underbody coating is usually a dense cladding (often based on rubber) applied uniformly to the undercarriage of the automobile. It is normally sprayed or painted on when the car is just out of the dealership and is clean. But even if you are getting the undercoating applied after a couple of years, it’s fine too. This is because it can prevent further damage to the undercarriage.
The main purpose of undercoating is to check rust, especially in the body components like frame rails along with other exposed metal parts. Underbody coating can also reduce wear and tear.
Various Kinds of Automotive Underbody Coatings:
- Rubberized Underbody Coating.
- Wax-Base Underbody Coating.
- Asphalt-Based Underbody Coating.
- Polyurethane Underbody Coating.
Rubberized Underbody Coating:
This is generally thought of as the best underbody coating for your car. It preserves the underbody well, protecting it from scratches. Applying this to the undercarriage is not much of a hassle either.
Rubberized Vehicle underbody coating is easy to apply and offers sound-cushioning as well as protection from dust, moisture, and dings or dents.
In addition to your undercarriage, rubberized undercoating is also safe to use on wheel wells and quarter panels, and dries to a soft rubbery finish that prevents further rust, damage, or moisture seeps. The coating can be painted over and, if necessary for bodywork, can be easily removed with an undercoating removal spray.
Overall, the rubberized coating is generally the best option for protecting your vehicle's undercarriage, as it provides the simplest and best protective measures against rust and moisture.
- Heavy-duty undercoating seals protect & insulate.
- Rubberized for maximum durability.
- Excellent professional blend all-purpose coating.
- Use it for rust prevention, sound deadening, abrasion resistance and more.
- Seals: frames, rocker panels, wheel wells and more.
- Fully cures in 24 hours at 77°F (25°C).
- For best adhesion apply to a clean, dry surface.
- Tap the bottom of the can to loosen the agitator ball then shake well.
- Apply a uniform coating by holding a can 10-12 inches away from the surface.
- Multiple coatings can be applied, allow 15-20 minutes between coats.
Wax-Based Underbody Coating:
This – more or less – ephemeral undercoating will wear away in a few months’ time. On the upside, wax-based undercoating puts up a big fight against moisture. It is also the most affordable option out there.
A paraffin-based undercoating will be the cheapest and quickest option available with which to protect the undercarriage of your vehicle. However, keep in mind that it will wear off quicker than other types of undercoating and will need to be stripped and reapplied at least once every year.
Wax-based undercoatings never truly harden. During application, they drip or flow into seams and cracks to provide protective properties. They are usually available in a spray gun canister or in an aerosol can and offer at least a base protection in moderately humid climates.
Wax-based underbody coating spray is primarily used on wax-coated vehicle underbodies and partially for the secondary treatment of all protective coatings, like those based on PVC, PVC/wax, bitumen/rubber and rubber/resins. In addition, the material has proven successful for the following applications.
- Secondary treatment of inaccessible areas, such as corners, edges, seams etc. Where rust spots are preferably formed.
- Addition of existing coating material based on PVC, bitumen/rubber, rubber/resins and wax.
- For selective applications and for repair coating of all underbodies after an accident.
Asphalt-Based Underbody Coating:
Best suited for lorries, trucks and large vehicles this provides a greater degree of protection compared to rubber-based coatings. However, asphalt-based coatings contain little amounts of rubber for sound-insulation purposes. The process of applying this coating is a bit time-consuming though.
For standard vehicles, any of the aforementioned types of undercoating will provide sufficient protection. For large trucks and heavy machinery, asphalt-based undercoating provides a bit of extra durability against rocks, chips, and moisture.
Asphalt-based undercoating generally contains a little bit of rubberized material that sets up firmly and also helps soften noise. Generally sold in five gallon containers, this type of undercoating also needs more cure time than the other three, and is NOT paintable, making it best to use only for undercarriages.
Polyurethane Underbody Coating:
This coating closes up splits and fractures on the underbody of the vehicle. It offers up good protection against corrosion and also bonds with the metal. Unlike in the case of asphalt-based coating, you can paint over the polyurethane coating.
The other option for undercoating your vehicle is to use a polyuethane-based sealant. This type of vehicle undercoating is a little bit quicker and easier to apply.
Polyurethane Undercoat is a two-pack modified polyurethane based on the chemical reaction of polyfunctional acrylic and isocyanate based material. Specially designed undercoat for exterior and interior masonry and wooden surfaces.
Oftentimes, polyurethane undercoating will come in canisters ready to preload into an application gun. This type of sealant works by seeping into all cracks and seams, displacing salt and moisture and oozing around rusty areas to bond with and protect unoxidized metal. It also sands quickly in case you'll need to perform bodywork and can be painted over.
On the flipside, this type of car undercoating generally requires a little bit more surface prep work before applying -- sanding and applying an etching primer to bare metals before using are generally recommended.
- Excellent mechanical film properties such as film hardness, adhesion, scratch and abrasion resistance.
- Good algae and fungi resistance.
- Highly resistant to splash and spillage of corrosive chemicals, solvents and detergent.
- Excellent adhesion on old epoxy and polyurethane painted surfaces.
- Provides a very stable base coat for subsequent coat.
- Easy application.
Modern Automotive Underbody Coating Processes:
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Pretreatment: removes and cleans excess metal and forms an appropriate surface structure enabling bonding of a corrosion protection layer.
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The next step is electrodeposition (ED) of the anti-corrosion or rust prevention layer.
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A sealer like Poly Vinyl Chloride (PVC) is applied for anti-corrosion, elimination of water leaks, and minimization of chipping and vibrational noise.
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A primer is then applied to promote adhesion between the surface and the basecoat; it also imparts a smoother surface for subsequent layers and has anti-chipping properties.
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Finally, the topcoats that include a basecoat and clearcoat are applied; they provide surface properties that are sought after, including colour, appearance, gloss, smoothness, and weather resistance.
Pro's and Con's of Underbody Coating:
Pro's:
- It provides a layer of protection against corrosion.
- It will extend the life of your vehicle.
- It can be applied to damaged areas.
- It can be self-applied.
- There are multiple undercoating methods that can be used.
- The service might help with the cost of your insurance.
- It may help to reduce interior noise.
Con's:
- It is less helpful if corrosion is already present.
- It works best on new cars.
- Most vehicles make it five years before corrosion begins to show.
- A third-party undercoating service might void your vehicle’s warranty.
- It adds weight to the vehicle.
- An undercoating is not impervious to damage.
- It must be reapplied every 3 to 5 years for the best results.
Underbody Coating:
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