Underbody Coating
UNDERBODY COATING
What is underbody coating ?
As the name sugest the under body coating is a thick layer of protective coating (asphalt/latex based usually) that is applied to the undercararge to protect from chipping and rust proofing. This is done after the paintjob or after the total assembly of the vehicle depending on the plant process cycle. The under body coating may be thick on different locatition of the vehicle where it is more more probable of damage . Also the OEM may impliment a different amount of underbody coating depending on the location where the car is being manufacured.

TYPES OF UNDERBODY COATING:
- Rubberised undercoating: Rubberised undercoating 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, 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.
- Polyurerthane undercoating: The other option for undercoating your vehicle is to use a polyurethane-based sealant. This type of vehicle undercoating is a little bit quicker and easier to apply. 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.
- Paraffin-based undercoating: 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.
- Asphalt based undercoating: 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.
Pros:
- Prevents stone chip damage – A car underbody coating provides a durable elastic over the underbody and wheel arches which protects the substrate from stones, gravel, salt, and other debris which is thrown up by the road.
- Protects from corrosion – The automotive coating process consists of at least five layers of protective and decorative paint. However, the underbody only receives the first two layers – the layers that provide the corrosion protection. But if that is the case why would another layer of coating be needed to protect from corrosion? The initial two layers provide corrosion protection, but are not very durable. Stone chip damage may expose the metal itself, leading inevitably to corrosion.
- Prevents water ingress – By covering cracks in the paintwork or joints in the undercarriage of a vehicle, moisture or water from humid or wet environments is prevented from creeping into the underbody and causing corrosion.
- Minimises sound – The noise of debris hitting a vehicle, or vibrations from the road can be dampened by the application of a car underbody coating. They prevent vibrations and because they are elastic they make far less noise when struck than the metal underneath.
- Is easy to maintain – Giving the undercarriage of a vehicle a uniform appearance means cleaning it down is simpler and so is identifying possible problems.
Con:
- It is less helpful if corrosion is already present.: For an undercoating to be the most effective, it should be in place before the underbelly of your car begins to rust. If you apply it over corrosion, you will still isolate the metal from further moisture and airflow, which is good, but the existing oxidizing/rusting process will still continue to occur. After rust is already present, applying an undercoating will slow the continuation of the corrosion process and will make your vehicle look better… until the rust breaks its way through the layer of undercoating you’ve applied. If you have rust present, it is better to remove the rust and then apply the undercoating.
- It works best on new cars.: If you’ve purchased a used vehicle, then the cost of preparing the underbelly for an undercoating might be more than the value of the car. You must remove all the residue from the bottom before it can be applied. Failing to do so will seal in the debris that is present already, which can lead to more problems. The best time to have an undercoating applied is when a vehicle is purchased new because it offers a superior level of protection then.
- Most vehicles make it five years before corrosion begins to show.: For vehicle owners who purchase something new every 3 to 5 years, then rustproofing may not be a good use of your cash. Although an undercoating does add value to a used car, that only applies when the rustproofing product used provides a transferrable lifetime warranty. Most vehicles that are on the road today are able to make it five years before any corrosion begins to show. It may be 7 to 10 years before the functionality of the vehicle is negatively impacted by the lack of an undercoating.
- A third-party undercoating service might void your vehicle’s warranty.: Some new cars no longer need the undercoating service provided because the structure of the vehicle has it built-in already. If you hire a third-party provider to apply an undercoating, you could void the corrosion-perforation warranty that is factory-provided. Most vehicles today that leave the factory floor are all provided with included rust-proofing.
- It adds weight to the vehicle. Although the amount of weight added to a vehicle with an undercoating is minimal (between 10 to 20 pounds for most vehicles), there is a small element of fuel economy to consider. When your vehicle weighs more, the distance you can travel on a single tank of fuel is reduced. The undercoating might reduce your efficiency by up to one mile per gallon, which creates a small additional fuel cost over time. Still, the effect on mileage of this additional weight is negligible compared to the effect a driver can have by the way they drive.

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