Corrosion of the lower part of the body often begins with damage to the paintwork on the thresholds due to constant contact with sand and reagents. Recovery of the protective layer at this location requires immediate intervention, as rust quickly spreads through the hidden cavities of the metal. Quality Painting the Threshold of a Car with Your Hands allows not only to return the aesthetic appearance, but also to extend the service life of body elements, preventing through holes.
The restoration process takes a considerable time and requires strict adherence to surface preparation technology. Errors in the degreasing or grinding phase will lead to the flaking of the material after a few months of operation. In this guide, we will take a look at all the steps of the job, from the removal of the linings to the finish polishing, so that you can get the job done professionally in garage conditions.
Diagnostics of damage and choosing a repair strategy
Before starting work, it is necessary to objectively assess the condition of the metal to understand whether cosmetic painting will be enough or welding will be required. Visual inspection often does not give a complete picture, so you should knock the problem areas and check the thickness of the coating with a thickness gauge. If you have a swelling of paint, this is a sure sign that corrosion I've already gone under the LCP layer and reached the inside of the threshold.
Depending on the depth of damage, the recovery method is chosen: local painting with transition or complete digestion of the outer part. For small chips and scratches that do not touch the metal, polishing and local coloring are suitable, but deep defects require stripping to metal. It is important to determine whether the interior is affected, as external paint without treatment from the inside will only give a temporary effect.
If you are planning to sell a car in the future, it is worth considering a more radical repair than just masking rust. Buyers often check the thresholds first, and the presence of traces of corrosion can significantly reduce the market value of the machine.
⚠️ Warning: If a deaf sound is heard or metal is flashed with a finger, simple painting is useless - replacement or serious welding of the damaged area is necessary.
Required tools and materials
The quality of the result directly depends on the materials used, so you should not save on soil and paint. To work, you will need a set of abrasive materials of different grains, ranging from P80 for rough cleaning and ending with P600-P800 for grinding the soil. Particular attention should be paid to the choice epoxyIt provides the best adhesion and anti-corrosion protection of the metal.
In addition to consumables, a specialized tool, including a grinder, spray gun or aerosol cylinders, and a compressor. To protect the surrounding surfaces, paint tape, cover film and a solvent for degreasing will be needed. Don’t forget about personal protective equipment: respirator, gloves and glasses, as solvent vapors and dust are toxic.
List of the main materials for quality restoration:
- 🛠️ Degreasing (antisilicone) and rags without pile
- 🎨 Automotive enamel (basic paint) and varnish
- 🧱 Fibreglass putty for deep dents
- 🌬️ Soil filler and epoxy primary soil
When choosing paint, make sure that the shade code matches the color of your car as indicated in the technical documentation or on the plate in the doorway. If the code fades or the machine is repainted, computer color selection may be required in a specialized laboratory.
Surface preparation and dismantling of elements
The best result is achieved with the complete dismantling of plastic linings and moldings, which allows you to process the hidden edges of the metal. Removing items requires care not to break plastic clips, which often become brittle from time to time. After dismantling, access to the lower part of the threshold is opened, where moisture and dirt most often accumulate.
The cleaning process begins with the removal of old varnish and paint in and around the area of damage by 5-10 centimeters. Use it. Bulgarian with a sweeping circle, you need to be careful not to overheat the metal and not to disturb its geometry. For finishing, it is better to use an eccentric grinder with abrasive P180-P240.
☑️ Checklist of preparations
If corrosion remains on the surface, they must be etched with a special rust converter, although mechanical removal is considered a more reliable method. After cleaning, the surface is thoroughly blown with compressed air and degreased. It is important not to touch the prepared metal with your hands, since skin fat will worsen soil adhesion.
Spattle and roasting of the body
To level out deep defects, a putty with fiberglass is used, which has high strength and moisture resistance. Apply the material in thin layers, allowing each layer to dry completely before applying the next. Excess putty is removed with a spatula, and after polymerization, the surface is grinded to perfect smoothness.
Printing is a critical stage that determines the durability of repairs, so you can not miss the application of epoxy soil. A thin layer is applied to the pure metal. epoxyIt creates a chemical bond with the metal and blocks the access of oxygen. After drying the epoxy, an acrylic filler soil is applied to level the microrelief.
| Type of material | Drying time (20°C) | Appointment |
|---|---|---|
| epoxy | 12:24 hours. | Anti-corrosion protection |
| Sound filler | 3-4 hours | Surface leveling |
| Putty | 20-30 minutes | Rebuilding geometry |
| Acrylic lacquer | 24 hours. | Protection and brilliance |
After drying, the soil is grinded with an abrasive P400-P600 under painting. If small risks or pits are identified, the process of spatling and priming is repeated locally. Ideally prepared surface should be matte, smooth to the touch and have no differences in height.
Paint and lacquer technology
Dyeing is done in a clean, well-ventilated room with a minimum amount of dust, as any mottled mutt will spoil the appearance. The paint is applied with a spray gun in 2-3 thin layers with interlayer drying, specified by the material manufacturer. Movements should be smooth and uniform to avoid sweating and uneven overlapping of color.
Nuances of metalworking
When working with paints such as "metallic" or "pearl" it is important to observe the same distance of the torch to the surface and the speed of passage. Uneven application will lead to the appearance of spots (apples), which will differ in shade under different lighting. The last layer of metal is often made more foggy (sputter) for proper stacking of grain.
After drying the base enamel, which usually takes 15-30 minutes, a car lacquer is applied. Lacquer protects the paint from ultraviolet light and mechanical influences, and also gives depth to the color. Apply varnish in 2 layers, controlling the spreading so that the surface becomes glossy and smooth.
It is important to observe the temperature regime: the optimal temperature for painting is 20-22 degrees Celsius. At lower temperatures, materials may not polymerize correctly, and at high temperatures, they may dry too quickly, forming a shaft.
⚠️ Warning: Do not try to accelerate drying with a building hair dryer or heater near fresh paint - this will lead to boiling of the solvent and the appearance of defects.
Assembly, drying and polishing
Full polymerization of the paint coating takes from 24 hours to several weeks, but you can assemble the car in a day. Installation of plastic linings and moldings should be done carefully so as not to scratch fresh varnish. If a sealant for the edges was used, it must dry completely before installing the elements.
Finish polishing is performed 3-4 weeks after painting, when the polish finally gains hardness. Polishing allows you to remove fine shaking, dust and light scuffs, making the transition between old and new paint invisible. For this purpose, a polishing machine with circles of different rigidity and polishing pastes are used.
Regular care for the restored threshold will extend the life of the coverage. It is recommended to wash the car with special shampoos and periodically treat the thresholds with wax or ceramic composition for additional protection from reagents.
The secret to success is that 90% of the quality of painting depends on the thoroughness of the surface preparation, not on the technique of applying paint.
Frequently Asked Questions (FAQ)
Can I paint the door without removing the lining?
Theoretically, it is possible, but the quality will be low. Under the linings will remain rust, which in six months will come out, and the border of the paint will be visible. Professional repairs require dismantling.
What paint is better to paint the thresholds?
It is best to use two-component car enamel with a hardener. They are the most resistant to abrasion and chemical effects. Aerosol cans are only suitable for temporary or very budget repairs.
Do I need to remove the door to paint the door?
Remove the door is not necessary, but desirable. This will simplify access to the upper edge of the threshold and will make a high-quality transition (stuffing) of paint to the rack and wing, making the repair invisible.
How much dried paint on the doorstep?
Basic paint dries for 15-30 minutes, varnish - a few hours before the lip. However, the full hardness of the coating is gaining within 14-28 days. During this period, it is not recommended to wash the car with chemicals and expose the thresholds to strong mechanical stress.