Rust is the main enemy of any car, capable of turning body iron into a sieve in a matter of seasons. That's why. epoxy It has become the gold standard for corrosion protection in professional body repair. It creates an impermeable film on the metal surface, which blocks the access of oxygen and moisture, stopping oxidative processes.
Unlike acidic (phosphate) analogs, this type of primer does not require contact with metal to activate, but rather acts as a powerful insulator. Right. epoxy ensures the adhesion of the subsequent layers of putty and paint, ensuring the durability of repairs. However, working with two-component systems requires strict adherence to the technology, otherwise the expensive material will turn into a useless layer that can swell in a year.
In this article, we will take a closer look at how to prepare a surface, mix components and coat it so that it lasts for decades. You will learn about the subtleties of working with Hardener You will understand why haste in this process is unacceptable.
The principle of operation and advantages of epoxy protection
The main task of this material is to create a chemically inert barrier. After polymerization epoxy It forms a dense structure that physically does not allow water and salt molecules to pass through. This fundamentally distinguishes it from rust converters, which change the chemical composition of oxides, but do not always guarantee complete insulation.
A key advantage is high adhesion to different types of surfaces, including galvanized steel, aluminum and even old paint coatings, if they hold firmly. Two-pronged soil after drying becomes an excellent basis for applying polyester putty, preventing their shrinkage and detachment.
⚠️ Warning: Epoxy soil can not be applied over the putty! Putty is hygroscopic and absorbs moisture, and epoxide will seal this moisture inside, leading to bloating and corrosion. The order of the layers is always this: metal → soil → putty (if necessary) → soil-filler → paint.
Another important aspect is mechanical strength. The dried layer is resistant to chips and scratches, which is especially important for the bottom, rapids and arches of the car. Anti-corrosion properties They persist even when the upper layer of paint is damaged, since the soil itself is not subject to oxidation.
Use epoxy soil to preserve the cleaned metal if you plan to continue repairing it in a few days or weeks. It reliably preserves the surface.
Essential tools and remedies
Before starting to mix components, you need to prepare the workplace and protect yourself. Solvent vapours and components epoxy They are toxic and can cause severe allergic reactions. Working in an unventilated room without protection is strictly prohibited.
For high-quality application, you will need a pneumatic spray gun with a duse of a suitable diameter. For primary soil, a nozzle is usually used 1.3–1.5 mmThis allows you to get a small torch and a flat coating. You will also need measuring tanks with calibration to accurately observe the proportions.
List of mandatory personal protective equipment:
- 🛡️ Respirator with carbon filters of protection class not lower than A1 or A2.
- 🧤 Nitrile or latex gloves resistant to chemical solvents.
- 👓 Protective glasses to prevent splashes from entering the eyes.
- 👕 All-clothing covering open areas of skin.
Don't forget that isocyanatesOften contained in hardeners, have no odor, but are extremely harmful to the lungs. Even if you think the room is well ventilated, using a respirator is a must-have technology requirement.
Preparation of surface for priming
The quality of the finishing surface is 80% dependent on the preparation of the base. epoxy It requires that the surface be absolutely clean, dry and defatted. The presence of oils, silicone or dust will cause the material to simply not lie down or peel off along with the paint.
First, a mechanical cleaning is performed. Using a grinder with an abrasive P80-P120All rust is removed to pure metal. It is important to remove not only visible corrosion foci, but also to clean the transition zone around them. After mechanical cleaning, the surface is blown with compressed air.
☑️ Checking surface readiness
The next step is degreasing. Use a special one. antisilicone Then you have two squirts, one of which is a dry one, and the other one is a dry one. Movements should be reciprocal so as not to smear dirt on the edges.
If there are areas with remnants of old paint or soil on the parts, they must be wrapped. This is done with abrasives. P180-P240. Glossy surfaces will not provide the necessary adhesion, so matteness is a prerequisite. After matting, dusting and degreasing are again carried out.
Mixing proportions and preparation of the mixture
Epoxy soil is sold in the form of two components: the base and hardener. Mixing proportions are strictly regulated by the manufacturer and are indicated on the bank (usually this ratio is the same). 1:1, 4:1 or 5:1 by volume). Violation of these proportions will lead either to non-sweetening of the material or to its excessive fragility.
Use a clean stainless container to stir. First pour the right amount of base, then add the hardener. Mix the components thoroughly for 2-3 minutes, lifting the material from the bottom so that the mass becomes uniform in color and consistency. The lifetime of the mixture After mixing, the pot life is between 30 and 60 minutes, so don’t cook more than you’ve spent.
The viscosity of the material may depend on the temperature in the paint chamber. If it's cold in the room, epoxy becomes thicker, and for normal spraying, the addition of a special diluent (no more than 5-10% of the volume) may be required. However, it is best to work at a temperature. +20°C.
What happens if you add too much hardener?
Excess hardener makes the coating fragile. It can crack when the body vibrates or hits. In addition, the life time of the mixture in the tank is reduced, and you risk not having time to unload the part before polymerization in the spray gun.
Before pouring into the spray gun, be sure to strain the mixture through a funnel with a mesh filter. This will remove possible lumps and prevent clogging of the dusa, which is especially critical when working with fast-drying compounds.
Application and drying technology
Application epoxy It is performed in 1-2 wet layers. The distance from the torch to the surface should be about 20-25 cm. The movements of the gun should be uniform, with a 50% overlap of the previous lane.
The first layer is applied with a thin, so-called "stick" layer. This is to improve adhesion. After 10-15 minutes (the time of interlayer drying), a second, full-fledged wet layer is applied. It should look glossy immediately after the torch passes.
| Parameter | Meaning/Recommendation | Note |
|---|---|---|
| Pressure in the spray gun | 2.0 to 2.5 atm. | At the entrance to the gun. |
| Diameter of a duo | 1.3. - 1.5 mm | For standard soils |
| Interlayer pause | 10 - 15 minutes | At +20°C |
| Complete polymerization | 12-24 hours | Depends on the thickness. |
Suit epoxy It's going in two stages. Primary polymerization allows you to apply the putty in 30-60 minutes (if the instructions for a particular product allow). The complete drying required for zero grinding or painting takes significantly longer – usually around 8-12 hours at room temperature.
Do not grind the epoxy soil "on dry" in the first hour after application. He has not yet gained strength and will score abrasive, turning into porridge.
If you use infrared drying, the process can be accelerated. However, the heating temperature should not exceed 60°Cnot to cause boiling of the solvent or deformation of the thin metal.
Grinding and further work
After drying out completely. epoxy You can grind. Abrasive is used to prepare for painting P240-P320. If you plan to apply a putty, the surface is simply wrapped up P180-P220 to create risks.
It is important to know that epoxy soils are very hard. When grinding, they can "salt" the skin, so use high-quality open-grain abrasives or grind with breaks. The dust produced by grinding is also toxic, so work in a respirator.
⚠️ Note: If after grinding the soil has passed to metal (dried), these places must be covered again with epoxy soil. The bare metal without protection will instantly begin to oxidize, and a corrosion center will appear under the paint.
For further work with filler or paint the surface should be clean and matte. If more than 24-48 hours have passed since the grounding (depending on the product), the surface may crystallize and lose adhesion. In this case, re-coating is required.
Compliance with technology epoxy This ensures that your car will be protected from rust for years to come. Do not save on materials and drying time, as the rework of poor-quality work will cost much more.
Can I apply epoxy soil to old paint?
Yes, it is possible, if the old coating is durable, does not peel off and has no defects. However, it must be wrapped with abrasive P240-P320 and degrease. You can not apply soil to glossy paint - it will not stick.
How to dilute thickened epoxy soil?
Only special diluents for epoxy materials or solvent 646/650 in very small amounts (up to 5-10%) can be used. The use of acetone or Kalosha gasoline is prohibited, as they can disrupt the chemical structure of the resin.
How much does epoxy soil dry at low temperature?
At temperatures below 15°C, the polymerization process slows down or stops. At +10°C, drying time can increase by 3-4 times. It is recommended to force-heat the room or use IR drying.