Correct application of metallic paint to a car body requires strict adherence to the technology of mixing the base and solvent, since the final shade and the absence of streaks depend on the proportions. The slightest deviation in the viscosity of the material or the speed of passage of the spray gun leads to an uneven distribution of aluminum powder, which is visually perceived as spotting or “apple-coloring”. Professionals know that metallized enamels behave differently than conventional acrylic paints, requiring thinner coats and specific drying times between coats to evaporate the solvent.
To get an ideal result, always use the same brand of solvent as the base, as the chemical composition must be completely compatible.
Painting mistakes metallic often occur due to incorrect settings of the spray pattern or ignoring the temperature conditions in the chamber. If the base is too wet, the metal will rise to the surface and create dark spots; if it is too dry, the coating will be matte and rough. In this article, we'll break down each step of the process so you can avoid costly rework and achieve a factory-quality mirror finish.
Surface preparation and selection of materials
The quality of the final coating directly depends on how carefully the body preparation before applying the base. The surface must be perfectly smooth, grease-free and dust-free, since any defect under the metallized layer will become noticeable immediately after drying. Before starting work, you must make sure that the filler primer is completely sanded with P500-P600 abrasive and does not have any shrinkage cavities.
The choice of materials plays a critical role in the success of the event. You will need quality base enamel, a suitable solvent (fast, standard or slow depending on the room temperature) and two-component acrylic varnish. Do not skimp on solvent, as cheap analogues may contain impurities that will cause aluminum to float or change the tone of the paint.
⚠️ Attention: Never apply the base to a glossy surface without first matting, otherwise adhesion will be impaired and the paint may peel off in pieces during use.
To work you will need the following tools and consumables:
- 🎨 Spray gun with a 1.3 mm nozzle (optimal for the base)
- 🌡️ Pressure gauge to control outlet pressure
- 🧴 Degreaser and sticky wipes
- 🧤 Nitrile gloves and a respirator with a carbon filter
It is also important to prepare the room: the temperature should be between 20-22°C and the humidity should not exceed 60%. Violation of these parameters will lead to a change in the rate of solvent evaporation, which is critical for the formation of the correct structure metallic effect.
Setting up the spray gun and mixture viscosity
Before you start spraying, you need to set it up correctly. spray gun and bring the paint to working viscosity. Mixing the base with solvent is usually done in a 2:1 ratio or according to the manufacturer's instructions indicated on the can. Be sure to filter the finished mixture through a funnel with a mesh to prevent foreign particles from entering the tool tank.
Setting the spray pattern is key. The pressure at the outlet of the gun should be approximately 2-2.5 atmospheres, but the exact value depends on the viscosity of the material. To check, make a test pass on the test plate: the torch should be smooth, without breaks or “plush” edges.
There is a common misconception that the base needs to be poured “before the flow”. In fact, the first layer metallics are applied rather dryly to create an adhesive base and set the tone. The second and third layers may be a little richer, but without the formation of streaks.
| Parameter | Meaning | Impact on the result |
|---|---|---|
| Pressure | 2.0 - 2.5 atm | Too high will give fog, low - large shagreen. |
| Distance | 15 - 20 cm | Determines layer density and drying speed |
| Tilt angle | 90 degrees | Tilt will result in uneven distribution of metal |
Adjustment of the torch width should be maximum to ensure uniform coverage of large surfaces. If you're painting narrow parts or transitions, the fan can be reduced a little, but the main body panels need a wide fan.
Base coat technique
First pass base enamel is fundamental. Apply it in perpendicular movements, overlapping the previous strip by 50%. Movements should be fast and uniform, without stopping at the beginning and end of the passage. The goal of this step is to cover the primer and create a uniform color, but not necessarily to achieve opacity in one pass.
After applying the first layer, let it dry (usually 10-15 minutes at 20°C). The solvent should evaporate and the surface will become matte. If you start applying a second coat over a wet base, the metal will rise and form unsightly stains.
⚠️ Attention: Do not blow compressed air onto the surface to speed up drying between coats, this may introduce dust or oil from the compressor into the paint structure.
The second layer is applied similarly to the first, but you can slightly increase the overlap of the stripes to 60-70%. It is at this stage that the main color and distribution are formed aluminum powder. Watch the reflection of the light: if stripes are visible, it means that the paint has been applied unevenly somewhere.
☑️ Checklist before applying varnish
In some cases, especially when using complex three-layer colors (for example, Perla Effect), a third base or effect layer may be required. It is important not to overdo it here, so as not to lose the effect of depth.
Elimination of defects: apples and stripes
One of the most common problems when painting metallic is the so-called “appleness” - a spotty surface resembling the peel of an apple. It occurs due to the uneven distribution of metal particles, which often happens when the paint viscosity is incorrect or the spraying technique is violated.
If you notice streaks after the base has dried, do not rush to immediately fill everything with varnish. Mild bullshit can sometimes be corrected with an additional control coat (fog spray) from a greater distance and at a higher pressure. This will help “accelerate” the metal and even out the tone.
However, if the defect is serious, you will have to grind the surface with P800-P1000 abrasive and start the base application process again. Trying to cover strong streaks with varnish will only preserve the defect and make it even more noticeable at an angle.
The secret of the masters
Experienced painters often use the criss-cross method for difficult colors, applying a layer horizontally and the next one vertically, ensuring a perfect overlap.
It's also worth considering that some colors (especially silver and light gray) are more prone to defects than darker shades. They require special care and cleanliness in the work area.
Varnishing and finishing
After the base has completely dried (usually 30-60 minutes, but it is better to follow the instructions for the specific product), you can begin to apply acrylic varnish. The varnish protects the base from ultraviolet radiation, chemicals and mechanical damage, and also adds depth to the color. Before varnishing, be sure to walk over the surface with a sticky cloth to remove any accumulated dust.
The varnish is applied in 2-3 layers. The first layer is a thin, binding layer (spray), the second is the main, wet one, and the third (if necessary) is for gloss and leveling of shagreen. It is important not to overdry the interlayer pause so that the layers of varnish polymerize together, creating a monolith.
The time for complete polymerization of the varnish ranges from 24 hours to several weeks, depending on the temperature. Only after this can you begin polishing, if necessary to remove shagreen or dust particles.
| Stage | Drying time (20°C) | Sign of readiness |
|---|---|---|
| Base (1 layer) | 10-15 min | Complete matting |
| Base (final) | 30-60 min | No stickiness |
| Varnish (interlayer) | 15-20 min | Easy peeling |
| Varnish (operation) | 24+ hours | Full hardness |
⚠️ Attention: Do not try to speed up the drying of the varnish with heat guns immediately after application, this may lead to boiling of the solvent and the appearance of craters.
High quality varnish must be elastic and hard at the same time. Cheap varnishes may become cloudy or develop microcracks over time, so choose trusted brands.
Polishing and protection of the coating
The final stage of turning a painted part into a work of art is polishing. Even with perfect painting, shagreen or adhered dust may remain on the varnish. Polishing with abrasive pastes removes these defects and gives the surface a mirror shine.
You can start polishing no earlier than 24 hours after painting, but it is better to let the varnish sit for a couple of days. Use a polishing machine with wheels of different hardness: first a hard wheel and abrasive paste to remove shagreen, then a soft wheel and finishing paste for gloss.
The main secret to the durability of metallics is not only proper painting, but also regular washing and the application of protective polishes or ceramic coatings.
After polishing, it is recommended to apply a protective wax or ceramic compound. This will create an additional hydrophobic layer that will repel water and dirt, maintaining its appearance. metallic paint for many years.
FAQ: Frequently asked questions
How many coats of base do I need to apply for metallics?
Usually 2-3 layers of base are applied. The exact amount depends on the coverage of the particular color and the quality of preparation. The main thing is to achieve a uniform color without streaks before varnishing.
Is it possible to paint metallic without a spray booth?
Technically it is possible, but the risk of dust getting in and causing defects (shagreen, craters) increases many times over. For garage conditions, thorough cleaning of the room and moistening the floor before work is critical.
Why did the color become darker after varnish?
The varnish saturates the color of the base, making it deeper and darker. This is a normal physical effect. This is why test colors should always be varnished before color approval.
Which solvent is best for metallics?
It is best to use the original solvent from the same company as the base. If this is not possible, choose a solvent with the desired evaporation rate (standard for 20°C).