Car Rust Protection Tips & Applications.

Protecting your car from rust can help you to avoid unnecessary costly repairs or scrapping your vehicle in extreme circumstances. Surface rust can soon appear and become evident around the vehicle underbody when stone chippings and road debris hit the protective paint layer causing holes to appear revealing the bare metal underneath. This problem soon leads to iron oxide ‘rust’ forming on the surface, a chemical reaction caused by oxygen and water or moisture in the air.

Corrosive Road Salt

Corrosive Road Salt

Surface Water Ingress

Surface Water Ingress

Stone Chipping

Stone Chipping

Is it good to rust proof your car?

Whether you own a new or old car, protecting the underbody against water ingress from surface water during harsh weather conditions is an important part of vehicle maintenance. Also, did you know that rock salt used to clear roads from snow and ice is a corrosion accelerant when introduced into the iron oxide chemical reaction? This means rust proofing your car every couple of years is a good idea due to the increased risk with flooding in the UK. Applying a suitable car rust protection coating will help to prevent rusting, by forming a protective film barrier to stop oxygen reacting with the metal. Helping you to reduce maintenance costs and avoid the premature replacement of components and parts.


What is the best rust protection for a car?

To protect your car from rust you will find a wide range of prevention products including cavity waxes and underbody coatings on the Frost website including:

Dinitrol 4941 a black waxy bitumen-based underbody coating has excellent abrasion resistance characteristics and self-healing properties. The product can also be applied over Dinitrol 3125 HS a high solid cavity wax for the ultimate dual layer rust prevention. However, when applying Dinitrol 4941 a wet thickness of 700 microns must be achieved to ensure the rubbery coating layer provides the ultimate car rust protection.

If you are looking to paint the underbody with a suitable automotive paint, Zinga Cold Galvanising zinc coating is extremely effective. The anti-corrosion product contains 96% zinc and galvanises the chassis providing protection against rust. This innovative rust prevention product coating provides safe cathodic protection that is comparable to hot galvanising. Zinga Cold Galvani is also commonly applied to truck chassis and car body frames before painting.

Another great product is Eastwood 2K ceramic chassis black underbody coating. The car rust protection underbody chassis coating provides incredible abrasion resistance due to being formulated with specialist ceramic nano-technology. Whilst also providing excellent stone chip protection and must be used in conjunction with Eastwood 4:1 Urethane Activator. Applying this fast-drying underbody rust proofing product coating is very easy and creates a chemical resistant protective layer. Please note when spraying Eastwood 2k ceramic black chassis underbody coating, professional breathing apparatus must be worn. We also recommend spraying the underbody coating over Eastwood’s epoxy primer for increased durability.

We can also recommend another impressive car rust protection product Noxudol Auto-Plastone a black coloured bitumen compound paste that additionally provides road noise sound deadening. The moisture-repellent rubbery underbody car rust protection coating retains good elasticity for a long time irrespective of temperature conditions. This product is easy to apply with a paintbrush or spray equipment however, a 3-6mm layer thickness must be achieved to protect the chassis against de-icing salts.

Finally, for the ultimate car rust proofing underbody protection, we recommend POR 15 Rust Prevention Paint the black paint provides a permanent finish. When compared to other leading underbody rust proofing paints that peel, crack, chip, scratch or flake far sooner to enable rusting. Once sprayed or brushed onto vehicle underbody surfaces the rust prevention paint forms a rock hard non-porous flexible protective coating. This makes POR 15 an ideal solution for protecting the vehicle suspension and chassis area. For the best results, it’s advisable to clean the area with POR 15 cleaner and degreaser then apply POR 15 metal prep to dissolve any rust leaving a zinc phosphate coated surface for improved paint adhesion.

Dinitrol 3125 HS Cavity Wax (1 Litre)

£16.00 S305HS
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Dinitrol 4941 Black Underbody Coating Rust Preventive Fluid (1L)

£17.40 S315
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Eastwood 2K Ceramic Chassis Black Satin Underbody Coating

£74.99 50430
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Eastwood Urethane Activator 8 oz

£24.99 21854
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Noxudol Auto Plastone – Underbody Compound

£13.02 NOXAP1L
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POR-15 Gloss Black Rust Preventive Paint 113ml

5.00 out of 5
£11.99 P266

POR15 Semi Gloss Black Rust Preventive Paint 3.78L (US Gallon)

£153.60 P280SGBLACK
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Zinga Cold Galvanising System – Anti Rust / Corrosion Zinc Coating (5kg)

£119.99 S512


Frost Mini

Rust proofing Car Underbody

Applying a car rust protection underbody chassis coating is simple and can be conducted with a DIY application. However, preparation is key to ensure the underbody coating is correctly applied and providing the best protection possible for your vehicle. Whilst the car rust proofing process is relatively straightforward and simple, we recommend following the steps below and product application advice guide.

1) Before applying the car underbody rust proofing coating, you must prepare the work area and ideally spray the product in a clean environment. We also recommend masking the vehicle and treatment area to prevent overspray. You must also wear a ventilator or dusk mask and only apply the underbody car rust protection coatings in a well-ventilated room. Finally, it’s advisable to apply the car underbody rust proofing treatment on a day with low humidity for faster drying times.

2) When applying a underbody rust proofing coating, preparing the surface is very important to ensure all dirt and soiling has been removed. For this process, we recommend using a steam pressure washer and suitable cleaner & degreaser that will remove any surface salts already present. However, you must wait until the surface is completely dry before proceeding to apply the underbody rust proofing coating. Otherwise, surface moisture can become trapped underneath the chassis underbody rust proofing protective layer that will soon start rusting. With newer cars you will also need to remove all plastic underbody protective tray covers from around the chassis area and wheel arches prior to steam cleaning.

3) With older cars or when surface rust is evident we recommend removing any flaking parts with a wire brush. Then apply a compatible rust converter like Dinitrol RC 900 or rust remover to the affected area. When excessive rust is present additional sanding may also be required. If opting to treat the chassis area with a rust converter or rust remover, read the product specification to check they are over-paintable and suitable for your individual application requirements.

4) Usually, with most car rust protection underbody coatings, it’s possible to apply them with a conventional aerosol, paintbrush or by using
spray equipment ‘undercoating gun’ attached to an air compressor when seeking to achieve a professional finish. When applying to the surface we recommend layering the material to gradually build up the coating until the product manufacturer’s recommended thickness has been achieved. Not applying the correct thickness can soon lead to the car rust proofing coating prematurely failing with visible cracks soon appearing due to being very thin.

5) Once you have successfully applied the car rust proofing coating, it’s advisable to repeat the process every couple of years to ensure the underbody chassis remains protected. You should also conduct regular inspections for any cracks or evident holes appearing in the underbody protective coating layer. In most cases conducting simple minor repairs to the car rust proofing protective layer is quick and easy with an aerosol spray application.

Car Rust Protection Product Range

Whether you are looking to protect an existing vehicle underbody or currently working on a classic car restoration project. Applying and continually re-treating the vehicle underbody with a suitable rust protection treatment coating is an essential ongoing maintenance requirement. To view the full range of underbody car rustproofing treatment coatings including Frost Extreme Chassis Black Paint a popular treatment with Classic Car Owners please browse the car rust protection shop range.

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