Treatment of the internal cavities of the arches with specialized compounds is a critical procedure to prevent through corrosion, which often develops unnoticed from the outside. Many car owners ignore this stage, relying on the factory coating, but aggressive reagents and sand quickly destroy the protective layer, allowing moisture to access the metal. High-quality anti-corrosion treatment allows you to extend the life of the body for years and maintain its market value without expensive welding work in the future.
Doing this work yourself requires careful surface preparation and the right choice of chemistry, since applying a protective layer to dirt or rust will only give a temporary visual effect. Modern anti-corrosion materials have the ability to displace moisture and penetrate microcracks, creating an elastic film that does not crack due to temperature changes. It is important to understand that the application technology depends on the type of composition chosen: bitumen mastics, wax mixtures or polymer coatings require different approaches to preparation.
Before starting work, it is necessary to provide access to all hidden cavities, which often requires the dismantling of fender liners, mud flaps and decorative trims. If you skip even a small area, the oxidation process will continue with a vengeance under a new layer of protection, reducing all efforts to zero. That's why mechanical cleaning and degreasing are the foundation of a long-lasting result, and not just a formality.
In this manual, we will analyze all stages of the process, from choosing a tool to final drying, so that you can complete the job professionally and safely for your car. Correctly selected anticorrosive Not only will it stop rust, but it will also reduce the noise level from gravel hitting the wheel wells.
Diagnostics of the condition of arches and selection of materials
The first step is always a thorough inspection of the wheel arches for existing damage and areas of corrosion. You can visually assess the condition of the metal only after removing dirt and dismantling plastic lockers, which often hide unpleasant surprises. If you find blistering paint or red streaks, this is a signal that corrosion has already penetrated deep into the metal structure.
When choosing a protective equipment, you should focus on the operating conditions of the vehicle and the climate zone. For regions with harsh winters and an abundance of reagents on the roads, bitumen-rubber-based compounds are better suited, which create a thick, vibration-insulating layer. In milder climates or for newer vehicles with intact factory coating can be used wax or oily liquids that are easier to renew.
It is important to pay attention to the adhesive properties of the material, since some compositions do not adhere well to vertical surfaces and may run off during the drying process. A quality product must remain elastic after polymerization in order to compensate for body vibrations when driving over uneven surfaces. Poor quality sealant will quickly crack and begin to let moisture through, accelerating the destruction of the metal.
Necessary tools and workplace preparation
For high-quality processing, you will need not only the anticorrosive agent itself, but also a whole arsenal of auxiliary tools that ensure the convenience and safety of the process. The main equipment will be a compressor with a sprayer or aerosol cans with a long tube for hard-to-reach places. Also an indispensable assistant is spray gun with an adjustable torch, allowing you to apply the material in an even layer.
- 🛠️ Drill with metal brush attachments for cleaning rust and old coating.
- 🧴 Degreaser (anti-silicone) and rags for final cleaning of surfaces.
- 🔦 A powerful flashlight or spotlight for inspecting hidden cavities and monitoring the quality of application.
- 🧤 Protective gloves, respirator and goggles for safety when working with chemicals.
The workplace must be well ventilated, as vapors from solvents and anticorrosives are toxic and fire hazards. A garage with a lift or pit is ideal, but you can also work on a level area by lifting the car with a jack. Be sure to use safety glasses, since drops of the composition that get into the eyes can cause a serious chemical burn.
Prepare masking tape and covering material in advance to protect brake mechanisms, calipers and suspension elements from anticorrosion. If bitumen or wax compounds come into contact with brake pads or rotors, they can cause loss of braking performance and an unpleasant odor when heated. Brake system must remain absolutely clean.
Use masking tape to cover parking sensors and rear view cameras, if they are located in the processing area, so as not to stain their optics.
Technology for preparing surfaces for processing
The quality of surface preparation determines 90% of the success of the entire operation, so this stage should be given maximum attention and time. First, the arches must be thoroughly washed from dirt, sand and road chemicals using a high-pressure washer and special shampoos. After washing, the surface must be completely dry, since applying anticorrosive to wet metal will trap moisture and accelerate corrosion.
This is followed by mechanical cleaning of all visible foci of corrosion to bare metal. Use a drill with a brush attachment or a scraper to remove loose rust that won't adhere to the surface. If the rust has penetrated deeply and formed through holes, they must be welded or sealed with epoxy. sealant before applying the main layers.
The final stage of preparation is degreasing the entire area to be treated. Wipe the metal with a cloth soaked in degreaser, removing residual oil, bitumen and silicone. This will ensure maximum adhesion of the anticorrosive to the metal and prevent peeling of the protective layer in the future.
☑️ Preparation checklist
The process of applying anti-corrosion composition
Application of anticorrosive agent must be carried out at an ambient temperature of at least +10°C so that the material adheres well and polymerizes correctly. If you are using a composition that requires heating, follow the manufacturer's instructions, but do not overheat it so as not to lose its beneficial properties. Apply the material using even movements, trying to cover all hard-to-reach areas, stiffeners and welds.
Pay special attention to hidden cavities that cannot be reached visually. Use special spray tubes, inserting them into the technological holes and turning them 360 degrees to uniformly irrigate the walls. Spray must cover the metal with a thin but continuous layer, without gaps or drips.
To enhance protection, you can apply a second layer after the first has partially dried, if this is allowed by the instructions for a particular product. The thickness of the layer should be sufficient to absorb impacts from small stones, but not excessive, so as not to increase the weight of the car and not to upset the balance of the wheels. Properly applied anticorrosive looks like a homogeneous matte or glossy film.
⚠️ Attention: Do not apply anticorrosive to hot parts of the exhaust system or engine, as this may cause a fire or release toxic smoke.
Treatment of hidden cavities and hard-to-reach places
Hidden cavities of arches and sills are the most vulnerable places where corrosion develops most quickly due to lack of ventilation and constant accumulation of moisture. To process them, special elongated nozzles are used, which allow the composition to be fed deep into the structure. The pressure in the system must be optimal to create a fine mist that settles on the walls.
When working with internal surfaces, it is important not to overdo it and not to fill the drainage holes through which moisture should escape. Clogged drains will turn the arch into a bathtub, where water will stagnate and destroy the metal even under a layer of anti-corrosion. Check the condition regularly drainage channels in the process of work.
If the design of the car allows, it is recommended to remove the plastic fender liners and process the inside of the arches on both sides: both the metal side and the plastic side. This will create a double barrier for moisture and noise. In some car models, access to the upper points of the arches is possible only by removing the wheel arches or even interior elements.
Safety precautions when working with chemicals
Work only in a well-ventilated area or outdoors. Use a respirator with organic vapor filters, as prolonged inhalation of aerosols is harmful to the lungs. If the product gets on your skin, wash it off immediately with warm water and soap or a special cleaner.
Drying, quality control and operation
After applying the anticorrosive agent, the car needs time for the composition to completely polymerize and dry. Depending on the type of material and weather conditions, this process can take from several hours to a day. It is not recommended to travel on heavily trafficked roads or be exposed to rain during the first 24 hours after treatment.
Quality control of the work performed is carried out visually: the layer must be uniform, without bubbles, tears or unprotected areas. Pay special attention to areas around fasteners and welds, where application defects most often occur. If you find any gaps, they must be eliminated immediately before the material has completely hardened.
Regular inspection of treated surfaces will help to promptly identify damage to the protective layer and restore its integrity. It is recommended to check the condition of the arches at least once a year, preferably before the winter season. Timely renovation small scratches will prevent the development of large-scale corrosion.
The table below shows the comparative characteristics of popular types of anticorrosive coatings for arches:
| Type of composition | Service life | Noise insulation | Difficulty of application |
|---|---|---|---|
| Bitumen mastic | 3-5 years | High | Average |
| Wax spray | 1-2 years | Low | Low |
| Liquid plastic | 2-4 years | Average | High |
| Oil composition | 1 year | Missing | Low |
Main conclusion: The durability of anticorrosive coating depends not so much on the brand, but on the quality of surface preparation before application.
⚠️ Attention: If after treatment there is a persistent smell in the cabin, check the tightness of the seals and ventilation, as anticorrosive vapors could get into the air intake system.
Frequently asked questions (FAQ)
How often do you need to repeat the anti-corrosion treatment of the arches?
The frequency of processing depends on the type of material used and operating conditions. Bitumen mastics last 3-5 years, wax compounds require updating every 1-2 years. In regions with aggressive winter roads, it is recommended to carry out a preventive inspection annually.
Is it possible to apply anticorrosive coating over rust?
It is impossible to apply anti-corrosive agent over loose, flaking rust - it will continue to grow under the layer of protection. It is necessary to mechanically strip the rust down to the metal, treat it with a rust converter (if technology allows this) and only then apply anti-corrosive agent.
Do I need to remove the wheels to treat the arches?
Yes, removing the wheels is necessary for good access to the upper part of the arch and hidden cavities. Without removing the wheels, it is impossible to ensure uniform coverage and protection of the brake mechanisms from ingress of the compound.
How to wash off anticorrosive if it gets on the body or clothes?
Fresh anticorrosive agent can be removed with gasoline, white spirit or a special bitumen stain cleaner. Hardened bitumen layers are much more difficult to remove and may require mechanical cleaning or heating (with caution).
Does anticorrosive protection affect the car's warranty?
Repairing hidden cavities yourself usually does not affect the warranty unless factory communications or electrical damage has been caused. However, if you apply a thick layer of mastic to the exterior parts, it may raise issues with your auto body repair dealer.