If acrylic enamel Duxone, Mobihel or Vika thickened in the jar or does not apply well through the spray gun SATAjet 5000 - the problem is not in the equipment, but in the incorrect viscosity. It can only be diluted with compatible solvents, otherwise after drying it will appear. shagreen, cloudiness or layer peeling. Suitable for two-component acrylic enamels (2K) thinner with hardener in a strict ratio of 2:1:0.5, and for one-component (1K) - universal compositions like R-12 or specialized, for example, APP Universal.
The mistake most beginners make is to use the first solvent they come across (for example, 646 or acetone), not taking into account the base enamel. Acrylic paints are sensitive to the type of thinner: fast (for cold weather), slow (for the heat) and standard (18–22°C). Non-compliance leads to defects: if evaporation is too rapid, craters, with slow - smudges. Next, we will look at how to avoid these problems at each stage - from choosing a solvent to testing the viscosity with a viscometer.
1. Types of solvents for acrylic enamel: which one is suitable for your paint
Acrylic enamels are divided into one-component (1K) and two-component (2K), and each type requires its own thinners. Basic rule: never mix solvents of different brands with hardeners - this disrupts the chemical structure of the coating.
- 🔹 For 1K enamels: use universal thinners (R-12, APP Universal) or specialized for acrylic (Body 740, Sikkens Autoclear LV). They contain a mixture of ethers and alcohols that do not destroy the polymer base.
- 🔹 For 2K enamels: required hardener (for example, Vika HS) + thinner of the same brand. Proportion: 2 parts paint: 1 part hardener: 0.5–1 part thinner (depending on temperature).
- 🔹 For base acrylics (for varnish): thinners marked "Basecoat" (for example, PPG D8115). They evaporate more slowly, preventing orange peel effect.
⚠️ Attention: Solvents 646, 647 and acetone are aggressive for acrylic - they destroy binder polymers, leading to loss of gloss and cracking in 6–12 months. They can only be used for washing instruments, but not for dilution!
How do thinners differ in evaporation rate?
The rate of evaporation depends on the ambient temperature:
- Fast (for example, APP Fast) - for operation at +5...+15°C. Contain more volatile substances (acetates).
- Standard (Body 740) - for +18…+25°C. A universal option for most workshops.
- Slow (Sikkens Autoclear LV Slow) - for +25°C and above. Prevents leaks in hot weather.
2. Dilution proportions: table for different conditions
The optimal viscosity of acrylic enamel for a spray gun is - 18–22 seconds by viscometer DIN-4. Exceeding this value leads to rough texture, understatement - to transparent spots. The proportions depend on the temperature, type of paint and application method (manual or pneumatic).
| Enamel type | Temperature, °C | Proportion (paint:hardener:thinner) | Viscosity, sec (DIN-4) |
|---|---|---|---|
| 1K (without hardener) | 15–20 | 100:0:20–30 | 18–20 |
| 2K (with hardener) | 20–25 | 100:50:10–20 | 20–22 |
| 2K (base for varnish) | 25+ | 100:50:30–40* (slow thinner) | 16–18 |
| Matte acrylic | 18–22 | 100:0:10–15 | 22–24 |
*For hot weather (>30°C), increase the thinner ratio to 50%, but do not exceed, otherwise the strength of the coating will decrease.
Pour the thinned paint into a funnel with a 4mm hole. If the stream is interrupted after 18–22 seconds, the viscosity is optimal. For accuracy, use a stopwatch.
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3. Step-by-step instructions: how to thin the enamel for a spray gun
Before dilution filter the enamel through a 100–150 micron mesh to remove lumps and dirt. This will prevent the spray gun nozzles from clogging (especially important for models with a nozzle size 1.3–1.4 mm).
- Step 1: Preparing the Components
- 📦 Open the jar of enamel and mix with a mixer at low speed (300-400 rpm) for 3-5 minutes. This will remove sediment and bubbles.
- 🧪 Measure the hardener (for 2K) and thinner into separate containers. Use measuring cups or scales accurate to the nearest 1 gram.
- Step 2: Mixing
- 🔄 Pour the hardener into the enamel, stir for 2 minutes. Then add thinner in small portions, controlling the viscosity.
- ⏱️ After mixing, let the paint “rest” for 10-15 minutes (induction period). This is necessary to activate the hardener.
- Step 3. Application test
- 🎨 Apply a test layer to a test surface (for example, an old hood). Evaluate the uniformity of the coating and the drying speed.
- 🔍 Check out unstuck (time when dust stops sticking): for 2K enamels - 15–30 minutes at 20°C.
Added hardener (for 2K)|⬜
Solvent matches temperature|⬜
Paint filtered through 100 microns|⬜
Viscosity checked with a viscometer|⬜
The test layer is applied and dried|⬜
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⚠️ Attention: If after mixing the paint appears bubbles, let it sit for 5–10 minutes or treat it with an anti-silicone additive (PPG DCX61). Bubbles during painting will lead to craters on the surface.
4. Mistakes when diluting: how to correct defects
Even professionals make mistakes that appear after drying. Let's look at typical defects and ways to eliminate them. without repainting.
- 🟠 Shagreen (orange peel): occurs due to too rapid evaporation of the solvent or high pressure of the spray gun (>2.5 bar). Solution: polish the surface with abrasive
P1500–P2000with pasta 3M 09374. - 🟣 Cloudiness: Causes: incompatible diluent or moisture in the compressor. Solution: dry the part with an IR heater at 60°C for 1–2 hours, then polish.
- 🔴 Smudges: Excess diluent or slow evaporation. Solution: wait for it to dry completely (24 hours), then carefully sand off the stain with a block of water.
- ⚪ Spots of transparency: lack of coloring pigment or too thin consistency. Solution: Apply another coat with the correct viscosity (20-22 sec).
Shagreen|Cloudiness|Smudges|Spots of transparency|Never had a problem-->
If the defect occupies >30% of the area, repainting is inevitable. For this matte Scotch Brite surface P800, blow with compressed air and apply a new layer adjusting the proportions.
5. Thinners for popular brands of acrylic enamels
Paint manufacturers recommend using “original” thinners, but in practice analogues with identical chemical compositions are allowed. Below are proven combinations for brands represented on the Russian market.
| Enamel brand | Recommended thinner | Analog (budget) | Features |
|---|---|---|---|
| Duxone (2K) | Duxone Hardener + Thinner | APP Universal | Requires an induction period of 20 minutes. |
| Mobihel (1K) | Mobihel Acryl Thinner | Body 740 | Sensitive to humidity >60%. |
| Vika (basic) | Vika Basecoat Thinner | PPG D8115 | Thin to 16-18 sec for an even metallic finish. |
| Sikkens (2K) | Sikkens Autoclear LV | Lesonal 2K Klarlack-Verdünner | Compatible with hardener only Sikkens. |
💡 Advice: When purchasing an analogue, check the inscription on the label "compatible with acrylic 2K/1K systems". For example, thinner Body 740 suitable for 80% of enamels, but not compatible with Sikkens due to different chemical bases.
6. Thinning for manual application (brush or roller)
If painting is done without a spray gun (for example, local repair of a bumper or thresholds), the enamel is diluted more strongly - to the point of viscosity 14–16 seconds. This reduces the risk of brush marks but increases drying time.
- 🖌️ For brush: ratio 100:0:30–40 (paint:thinner). Use synthetic brush with soft pile (for example, Purdy).
- 🎨 For roller: 100:0:20–25. The roller should be foam rubber (not velor!) to avoid bubbles.
- ⏳ Drying time: at 20°C - 6-8 hours until tack-free, complete polymerization - 48 hours.
⚠️ Attention: When applied manually it's impossible use thinners with drying accelerators (for example, APP Fast) - they lead to uneven gloss and stripes.
Always apply enamel in 2-3 thin coats at 15-20 minute intervals. A thick layer will lead to smudges and prolonged drying (up to 24 hours).
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7. Storage of diluted enamel: how long does it retain its properties?
After mixing with a hardener (for 2K systems), the enamel has a limited lifespan:
- 🕒 At 20°C: 6–8 hours (before gelling begins).
- ❄️ At +5°C: up to 24 hours (curing reaction slows down).
- 🔥 At 30°C+: 2–3 hours (accelerates polymerization).
To extend the shelf life of thinned paint:
- Store in airtight container (for example, a jar with a rubber gasket).
- Add a layer on top thinner (1–2 mm) - this will create a barrier from oxygen.
- Place the jar in refrigerator (not a freezer!) at +5…+10°C.
If the enamel begins to thicken, do not dilute it again - this will disrupt the ratio of components and lead to peeling after drying. It is better to dispose of the leftovers and prepare a new portion.
Frequently Asked Questions
Is it possible to dilute acrylic enamel with water?
No, water is not compatible with organic-based acrylic enamels. She calls coagulation (coagulation) of paint and leads to whitish stains after drying. Only diluted with water waterborne acrylics (for example, PPG Envirobase), but they require special thinners (PPG DX330).
How can I replace the branded thinner if it is not on sale?
Use universal thinners marked "for acrylic 2K/1K", for example:
- Body 740 — for standard conditions (18–22°C).
- APP Universal — a budget analogue for 1K enamels.
- Lesonal 2K Klarlack-Verdünner - for European paints (Sikkens, Spies Hecker).
Test compatibility on a small area before use!
How to fix too thin enamel?
If the paint is too thin (viscosity <14 sec), add original enamel in small portions (5–10% of the volume), stirring after each. Do not use thickeners (for example, Aerosil) - they disrupt the structure of the coating. If the viscosity is <10 sec, it is better to prepare a new batch.
Why did the enamel become cloudy after dilution?
Cloudiness occurs for three reasons:
- Incompatibility of the thinner with the enamel base (for example, 646 for acrylic).
- Moisture ingress from the compressor or air (condensation).
- Too rapid evaporation of the solvent (typical for fast thinners at low temperatures).
Solution:
- Dry the part with an IR lamp at 60°C for 1–2 hours.
- Polish with abrasive paste
P1500. - If cloudiness remains, repaint with the correct thinner.
Is it possible to mix enamels from different manufacturers?
Mix different brands of enamels not recommended, even if they are both acrylic. Reasons:
- Different chemical basis (eg. Duxone - polyurethane-acrylic, Mobihel - pure acrylic).
- Unpredictable reaction with hardeners (risk wrinkling or peeling).
- Different drying times (may cause uneven gloss).
Exception: if enamels of the same line (for example, PPG Deltacron and PPG Omni), but even in this case, do a test paint job.