Corrosion of metal body elements is not just an aesthetic problem, but a real threat to the safety and durability of the car. Wheel arches are especially vulnerable when they are exposed to aggressive abrasives, reagents and moisture. Processing arches with cannon fat remains one of the most effective and time-tested methods of protection, despite the emergence of many modern analogues. This material is capable of creating an elastic, non-cracking film that retains its properties for decades even under extreme operating conditions.
Many car owners mistakenly believe that bitumen mastic or tar are a complete replacement for gun lard. However, the physicochemical properties of these substances are radically different. Cannon fat (or pushsalo) is a petroleum product thickened with fatty acids, which gives it a unique ability to self-heal microcracks. Unlike hardening mastics, it does not chip from impacts of gravel, but is only temporarily deformed, maintaining the tightness of the coating. That is why body repair professionals often recommend this particular composition for primary or restorative protection.
In this article we will analyze in detail the surface preparation technology, proper application methods and nuances that will help you avoid common mistakes. Well made anti-corrosion treatment extends the life of the body by 5-7 years, preventing through corrosion. It is important to understand that the result directly depends not only on the quality of the material, but also on the thoroughness of the preparatory work. Ignoring the cleaning or degreasing steps can ruin all your efforts by turning the protective layer into a moisture trap.
Chemical composition and benefits of cannon lard
The material is based on heavy petroleum oils, thickened with ceresin and paraffin, with the addition of corrosion inhibitors. This formula provides the substance with high adhesion to metal and the ability to displace remaining moisture from microcracks. Unlike synthetic compounds, cannon fat does not contain volatile solvents that evaporate over time, leading to shrinkage and cracking of the coating. This makes it an ideal choice for hidden cavities and high vibration areas.
The key advantage is temperature stability. The material does not flow in extreme heat (up to +90°C) and does not become brittle in the cold. Elasticity The film allows it to stretch and contract along with the metal of the body during thermal expansion. If a stone scratch forms on the surface, the viscous structure of the substance heals the damage, preventing oxygen from contacting the metal. This phenomenon is often called the "memory effect" of the material.
⚠️ Attention: Despite its high efficiency, cannon lard has low mechanical tensile strength. In areas subject to constant abrasive action (bottom, lower edge of arches), it is recommended to combine it with harder mastics or use it as a sublayer.
A comparative characteristic shows that the service life of high-quality gun lard in arches is from 5 to 7 years, while cheap bitumen mastics lose their properties after 2-3 years. In addition, rust inhibitors, included in the composition, continue to work even after application, passivating the oxidized areas of the metal. This is especially important for used cars, where it is not always possible to completely remove corrosion areas before treatment.
Necessary tools and preparation of the work area
High quality arch processing impossible without careful preparation. You will need not only the anticorrosive agent itself, but also a specialized tool. To heat the material, you need a water bath or a hair dryer with a thermostat, since an open fire can ignite the vapors. It is most convenient to apply the composition with a brush with stiff bristles or a special gun for thick mastics if you plan to work with the material heated to a liquid state.
The first step is always to remove the wheels and, if possible, the plastic wheel arch liners. This is the only way to gain access to hidden cavities and the tops of arches where the most dirt accumulates. If the lockers cannot be removed, they must be thoroughly washed from the inside with a stream of water under pressure, using special nozzles for arches. After washing, the surface should dry completely, ideally using a heat hairdryer.
List of required equipment and materials:
- 🧴 Cannon lard (calculation 1-1.5 kg per arch)
- 🔥 Construction hair dryer or water bath container
- 🖌️ Brushes, spatulas or anticorrosive sprayer
- 🧼 Degreaser (white spirit, solvent or special cleaner)
- 🛡️ Personal protective equipment (gloves, respirator)
After cleaning from dirt and sand, it is necessary to mechanically clean the corrosion areas. To do this, use metal brushes, sandpaper or a sandblaster (if possible). Removing loose rust — a critical stage: if you leave the oxidized metal, corrosion will continue to develop under the anti-corrosion layer, corroding the body from the inside. It is recommended to treat the cleaned areas with a rust converter, which will convert iron oxides into stable compounds.
Application technology: step-by-step instructions
The process of applying cannon lard requires compliance with the temperature regime. The material must be heated to 80-90°C. At this temperature, it becomes fluid, like sunflower oil, which allows it to penetrate into the smallest pores of the metal. However, it is impossible to overheat the composition above 100°C - this can lead to the loss of some of the beneficial properties and boiling. Heating is best done in a water bath to avoid local overheating and the risk of fire.
Heated cannon lard should be applied with quick, confident movements. If you use a brush, try to rub the compound into the metal rather than just spreading it across the surface. Pay special attention to welds, edges and mudguard attachment points. This is where it often starts pitting corrosion. The layer should be uniform, without gaps, but also without the formation of thick “sags” that can flow down during operation.
☑️ Checklist for preparation and application
For hard-to-reach places that cannot be reached with a brush, you can use the “cold application” method. To do this, a piece of hard lard is heated with a hairdryer directly on the metal, and then spread with a spatula or a hard brush. This method is less effective in terms of penetration, but allows you to treat local areas without dismantling the elements. After completion of the work, it is advisable to leave the car in a warm garage for a day for final polymerization and cooling of the composition.
Comparison with analogues and alternative methods
There are many products on the anticorrosion market, and the choice often confuses the owner. To understand the place of cannon fat in this hierarchy, let’s compare it with its main competitors. Bituminous mastics create a harder coating that provides better protection against stone impacts, but they are prone to cracking as they age. Liquid plastic (liquid fender liners) forms a durable polymer film, but at the slightest violation of the integrity, moisture gets under it and causes hidden corrosion, which cannot be noticed without removing the coating.
Oil anticorrosives (such as Movil) have excellent penetrating ability, but they do not dry completely and require regular updating. Cannon lard occupies the niche of the “golden mean”: it does not dry out completely, remaining plastic, but it also does not flow as actively as oils. This makes it ideal for older cars where the body already shows signs of metal fatigue and microcracks.
| Parameter | Cannon fat | Bitumen mastic | Liquid plastic | Oil anticorrosives |
|---|---|---|---|---|
| Elasticity | High | Low (hardens) | Average | Very high |
| Service life | 5-7 years | 3-4 years | 2-3 years | 1-2 years |
| Impact protection | Average | High | High | Low |
| Penetration | High (warm) | Low | Low | Very high |
It is important to note that modern wax-based synthetic compounds are often superior to cannon lard in terms of environmental friendliness and odorlessness, but their cost can be 3-4 times higher. For budget repairs or processing of a car preparing for sale in a few years, traditional cannon lard remains the most economically justified solution.
Before applying gun fat, a thin layer of primer can be applied to the rust-free areas. This will create an additional barrier and improve anticorrosive adhesion.
Common mistakes and how to avoid them
One of the most common mistakes is applying anticorrosive to a damp or poorly degreased surface. The water remaining in the pores of the metal will be preserved under a layer of fat, and the rotting process will accelerate. Degreasing - This is not a formality, but a necessity. Use white spirit or special cleaners, thoroughly wiping the metal with a clean rag before starting work.
The second mistake is insufficient heating of the material. Cold cannon lard forms clumps, does not penetrate microcracks and quickly peels off. The consistency should resemble liquid sour cream or butter. If you are working in a cold garage, the material will cool too quickly, so it is recommended to warm up the container with lard as you work.
⚠️ Attention: Do not apply gun lard to brake system components, rubber boots and electrical connectors. The material can destroy rubber and cause brake overheating if it comes in contact with pads or rotors.
The third mistake is ignoring drainage holes. There are holes for water drainage in the arches and sills of the car. If handled carelessly, they can be clogged with thick anticorrosive, which will lead to the accumulation of moisture inside the hidden cavities. Check and clean carefully drainage channels after completion of all work.
Care of treated surfaces and service life
After treatment, the arches become less susceptible to external influences, but this does not mean that you can forget about them. Once a year, preferably before the winter season, it is recommended to inspect the condition of the coating. If you notice mechanical damage or severe contamination, the area can be locally cleaned, degreased and a fresh layer of anti-corrosive applied. Coating repair does not require a complete rework of the entire arch; it is enough to treat the damaged area.
When washing a car with high pressure, try not to direct the jet at a right angle close to the arch coating, especially if it was applied a long time ago. Strong water pressure can damage the integrity of the layer. If you use active foam, make sure that it does not contain aggressive alkalis that can wash away the surface layer of anticorrosion.
The service life of the protection directly depends on the operating conditions. In urban traffic jams with reagents, the layer can thin out faster than in rural areas. However, even partial preservation of the film continues to protect the metal. If you're planning on selling a car, having a fresh coat of gunmetal in the arches is often perceived by buyers as a sign that the car has been cared for with care.
What to do if gun fat gets on the paintwork?
Fresh cannon grease can be easily removed with Galosh gasoline or white spirit. Dampen a rag with solvent and carefully wipe off any spills. Do not rub too hard to avoid damaging the varnish. If the lard has frozen, you can heat it with a hairdryer and remove it with a rag; remove the remaining residue with a solvent.
The main secret of durability is not so much the material itself as the quality of surface preparation. 90% of success is clean, dry and degreased metal before application.
Frequently asked questions (FAQ)
Is it possible to apply gun lard over old rust?
It can be applied, but it will not stop corrosion completely. Loose rust must be brushed down to the metal. If the rust is dense and focal, cannon lard will preserve it, slowing down the process, but it is better to treat such places with a rust converter before applying anticorrosive.
At what temperature is it best to process?
The optimal ambient temperature is from +10°C to +25°C. In a cold room, the material will harden too quickly, making application difficult. When applied, the material itself must be heated to 80-90°C.
Is gun fat washed off with water or chemicals at the car wash?
High-quality cannon lard does not dissolve in water and reacts poorly to alkaline shampoos. However, aggressive solvents (gasoline, acetone) can wash it off. Over time, the layer may become thinner due to the abrasive effects of sand and stones.
Do I need to remove the plastic fender liners for processing?
It is advisable to remove it. This will allow you to treat the inside of the arch, the upper edges and hidden cavities, which are the main sources of corrosion. Treating only the visible part of the arch is only 50% effective.