Threshold corrosion is one of the most common and painful problems faced by car owners, especially in regions with humid climates and aggressive use of road reagents. Water mixed with salt and dirt accumulates in the lower parts of the body, creating ideal conditions for rapid oxidation of the metal. If timely action is not taken, rust can for several seasons turn the power element into dust, which will lead to expensive body repairs or even loss of geometric strength of the body.
Many motorists wonder what is the best way to treat the internal cavities of the rapids to stop this process or prevent it from occurring. The modern market offers a wide range of solutions: from classic bitumen mastics to innovative foam compounds that penetrate the most inaccessible places. The choice of the right material directly depends on the condition of the car, the presence of already begun corrosion processes and operating conditions of the vehicle.
In this article, we will discuss in detail the main types of anticores, their advantages and disadvantages, as well as the technology of application. You will learn why regular paint does not save from rust and which formulations really work for the long term. Understanding the chemistry of the processes and the physical properties of the materials will allow you to make an informed decision and keep your car body in excellent condition for many years to come.
Why the Thresholds Are Ruining in the First Place
The design of automobile rapids is a closed or semi-enclosed cavity, which creates specific conditions for moisture accumulation. When the car is moving, the wheels lift water, dirt and salt from the road, which then settle on the bottom and in the niches of the wheel arches. The thresholds, being the lower part of the sidewall of the body, take the main blow of these aggressive liquids.
The main problem is that there are often no full drainage holes inside the sills, or they get clogged quickly. As a result, the moisture that has got inside cannot evaporate and remains in contact with the metal. Galvanic corrosion It is enhanced by the presence of an electrolyte, the role of which is performed by salt water. The situation is aggravated by the fact that the outside of the threshold can look whole, covered with paint, while the inside of the metal is already destroyed.
- 🚗 Mechanical damage: Stone strikes and sandblasting effect destroy the outer protective layer.
- 💧 Condensate: temperature changes cause the formation of condensation inside closed cavities.
- 🧂 Chemical aggression: Road reagents accelerate the oxidation of the metal at times.
Particular attention should be paid to the design of thresholds in modern cars. Often they consist of several layers of metal welded by spot welding. Between these layers of moisture flows instantly, and it practically cannot dry there. That's why. corrosion-proofing internal cavities is a critical procedure for prolonging the life of the body.
Types of anticorrosive compounds for processing
Choosing material to protect thresholds is not just a matter of price, but an understanding of how a particular chemical composition works. All funds can be divided into several main categories, each of which has its own specific application. The wrong choice can result in money being wasted and corrosion continuing to develop under the protective coating layer.
The most common are bitumen-rubber mastics. They create a thick, elastic layer that perfectly isolates the metal from moisture and mechanical influences. Such formulations often contain corrosion inhibitors and are used primarily for external treatment of the bottom and external surfaces of the thresholds. However, for internal cavities, they are poorly suited due to their high viscosity and the inability to penetrate deeply into microcracks.
For internal cavities where it is impossible to reach the brush, used liquid oil-based or wax-based. Their key feature is high penetrating ability. They displace water from the microscopic pores of rust and create a thin but strong film. Such funds include popular "movili", various wax sprays and foam anticores. They are most often “poured” inside the thresholds through technological holes.
⚠️ Attention: Never use quick-drying paints or nitro-emalee to treat the internal cavities of the thresholds. They are not elastic, crack when the body vibrates and do not have inhibitory properties, only preserving moisture under the coating layer.
Bitumen mastics and their features
Bitumen mastics are a thick, viscous substance of black color, the main component of which is bitumen. Modern formulations are often improved by rubber, resins and mineral additives, which increases their adhesion and elasticity at low temperatures. It is a "heavy artillery" in the world of anti-cows, designed to create a powerful barrier.
The main advantage of bitumen mastics is their ability to create a thick, noise-absorbing layer. They perfectly protect against the impact of gravel and sand, which is important for the outer part of the sills. However, before applying such compositions, careful surface preparation is necessary: removal of rust, degreasing and, preferably, the use of primer. Without this, the mastic can peel off along with pieces of rust.
There is a myth that bitumen mastics can "hit" the rapids from the inside. That's a dangerous misconception. Due to the high viscosity, the mastic will not flow into the far corners of the cavity, but will freeze at the entrance hole, blocking the access of air and creating a pocket for moisture. Tixotropy These materials mean that they don’t spread out on their own, which is good for vertical surfaces, but bad for hidden cavities.
- 🛡️ High mechanical strength: They can withstand the impact of stones and twigs.
- 🔇 Noise insulation: Reduce metal vibration and road noise.
- 🚫 Poor penetrating capacity: They are not suitable for the treatment of hidden cavities and joints.
For rapids, bitumen mastics are used mainly outside, after body repair, to protect welds and restore factory anti-gravel coating. As an internal anticory, they are useless and even harmful if you try to shove them inside through narrow holes.
Liquid anticores: washing, oils and waxes
When it comes to what is poured inside the thresholds, in 90% of cases we are talking about liquid compositions based on oils or dissolved waxes. The classic representative of this group is Movieville - a mixture of motor oil, olifer and corrosion inhibitors. Despite its old-fashioned nature, this principle of operation remains the most effective for preserving already begun processes.
Liquid anticores work on the principle of displacing water. Due to low surface tension, they flow into any cracks, expelling moisture from under the rust and stopping oxidation. The oil base allows the composition to remain mobile years, constantly tightening small scratches and damage. Wax compositions, in turn, after drying the solvent form a denser, paraffin film.
When buying liquid anticores, pay attention to the presence of a spray tube in the kit. Without a special nozzle - "goose neck" qualitatively treat the inner cavity of the threshold is impossible.
Modern analogues, such as foam-crustcombine the advantages of liquid and solid compositions. They are supplied in aerosol cylinders and foam when sprayed, filling the entire volume of the cavity. After polymerization, the foam settles, leaving a uniform layer of protective substance on the walls. This allows you to control the quality of the processing: you see (through the control holes) where the composition got.
It is important to understand the difference between “dry” and “wet” anticor. Oil formulations (wet) never dry completely and provide better protection, but can drip if damaged. Wax (dry) form a hard crust, which is better held, but when cracked, the protection is broken locally. For thresholds, it is oily, non-drying compositions that are more often recommended.
Technology of processing of hidden cavities
The quality of anti-corrosion treatment is 80% dependent on preparation and 20% on the material itself. Just spraying a spray into an existing hole is a waste of time and money. Technology requires a series of operations to be performed consistently, ignoring which will negate all efforts.
The first step is always the diagnosis and preparation. It is necessary to remove plastic linings of thresholds, if any, and assess the condition of the metal. If the threshold is already through, no anticor will not help - welding or replacement of the element is required. If the metal is intact or has surface rust, the surface is cleaned of dirt and degreased.
☑️ Checklist for preparation for processing
Then comes the application process. To do this, holes (usually 6-8 mm) are drilled in the threshold with a certain step so that the anticory jet covers the entire area. A special pistol is used with a long tube and a sprayer at the end, which is inserted deep inside. The processing is carried out progressively: from the far point to the near, evenly turning the balloon or pistol.
After treatment, the holes are closed with rubber plugs. It is important to give the composition time for polymerization (if it is drying) or spreading. In the first days after the procedure, it is better not to operate the car intensively, so that the anticor evenly distributed along the walls. It is critical not to close the drainage holes.If they are designed, otherwise the effect will be reversed.
Comparative table of anticorrosive agents
To simplify the choice, let’s organize information about popular types of tools. Different operating conditions and the condition of the car dictate the choice of a particular product. Below is a comparison of the main characteristics that will help to navigate the variety of proposals.
| Type of instrument | penetrating ability | Mechanical resistance | Term of service |
|---|---|---|---|
| Bitumen mastic | Low. | Tall. | 3-5 years |
| Oil Anticor (Moville) | Very high. | Low. | 1-2 years |
| Wax composition | Medium | Medium | 2-3 years |
| Foamy anticor | Tall. | Medium | 3-4 years |
As you can see from the table, there is no universal solution. For a new car with whole rapids, wax compounds or mastics for external protection are ideal. For age cars, where there is a high risk of hidden corrosion, the best choice will be penetrating oil compounds that can reach the rust foci.
Can you mix different anticores?
Mixing different types of anticores (for example, bitumen and oil) is not recommended. They can react chemically, curl up, or lose their properties. If you do not know what the car was treated before, it is better to use neutral trains or carry out a complete cleanup.
Common errors in self-processing
The desire to save on the services of specialized centers often leads motorists to self-processing, which, due to ignorance of the nuances, brings more harm than good. One of the most common mistakes is to apply anticores over dirt or, worse, over loose rust without pre-treatment with a converter.
The second common mistake is to use the wrong tools. Attempting to pour liquid anticores through a thin tube without a sprayer causes the composition to simply drain down to the lower part of the threshold, leaving the top and corners unprotected. Spray dispersion - a key factor in success.
⚠️ Attention: Do not seal all the technological holes after processing. The threshold should “breathe”, and excess moisture should be able to evaporate. Complete sealing can lead to accelerated rot from the inside.
The temperature is also often ignored. Applying anticores in a cold garage or in the cold makes the composition too viscous, it does not penetrate well into microcracks. Most manufacturers recommend working at a temperature not lower than +10 ... + 15 ° C.
The main secret of long-term protection is not so much the material itself, as careful surface preparation and the correct choice of anticores for a specific state of the metal.
Frequently Asked Questions (FAQ)
How often should the corrosion coating of the thresholds be updated?
The frequency of processing depends on the composition used and the operating conditions. Oil anticores (such as Moville) are recommended to be updated annually, as they gradually wash out and dry out. Wax and bitumen coatings last longer - from 2 to 5 years. Visual inspection through the drainage holes will help you understand whether retreatment is necessary.
Will the anticor if the threshold has already rotted through?
No, anticor is a preventive and preservative, not a material for repair. If the metal has lost its structural integrity (through holes have appeared), welding or replacement of the element is necessary. Pouring anticory into a leaky threshold will only temporarily mask the problem, but will not stop the destruction.
What is the best way to handle the rapids in winter or in a cold garage?
At low temperatures, most compounds lose their properties. If processing is vital, use special “winter” versions of anticores based on oils that remain fluid in the cold, or preheat the car and the room. However, the ideal option is processing in the warm season.
Do I need to clean the rust before applying anticores?
Yes, mechanical cleaning of loose rust is mandatory. If it is not possible to remove corrosion to metal, chemical rust converters that convert iron oxides into stable compounds should be used. Applying anticores to a loose layer only preserves the process of destruction under the film.