In PU painting techniques, including new painters entering the craft to the experienced PU sometimes encountered some mistakes when applying PU paint. These errors are sometimes due to paint, paint or poor workmanship, which results in errors in the application of paint that we do not find a solution. Understanding these difficulties, high-grade wood paint opec paint will present all the common mistakes in the PU paint process and remedies to help you easily overcome the product quickly.
1. The paint film is cracked bird's feet.
Phenomenon: The paint film has many cracks when dry.
- The liner or the underside of the sheet is too dry.
- Use different solvents or different suppliers.
- The product has not enough time to humidify the paint.
- When primer 1TP, 2TP coat. The coating will revitalize the lining.
- Between the layers should be dry to ensure the next coat, should not be too thick.
- Use the same solvent or a supplier.
- It is necessary to allow the wood to be moistened again after drying (moisture content is about 12 -> 14%).
- Primer, topcoat or 2TP primer, 1TP primer.
2. Powder coating film (needle flour).
Phenomenon: The paint film has many cracks when dry
- In the paint there are air bubbles.
- Reducing agent.
- Spray the bottom layer sprayed the next layer, spray too many layers overlap.
- The wooden pins too deep do not use the mop that spray too thick.
- After stirring to dissolve foam before use.
- Phase to supplier ratio.
- Allow the lower layer to dry completely before spraying the next coat. For coatings, spray should be about 40 -> 50 micrometres (equivalent to 2 -> 3 pads).
- For products with deep holes, we should paint thin film, should not paint too thick.
The paint is dull, milky white
3. The paint film is moldy or white.
Phenomenon: The paint film is cloudy, milky white.
- The air is too moist, and the vapor permeates the film.
- diluted solvent evaporates too quickly.
- In compressed air there is water vapor.
- Pay attention to air condition, add antacid when temperature is lower than 20oC.
Choose a thin layer of solvent suitable for the weather.
- The compressed air must pass through a filter that removes water and oil.
4. Orange paint film.
Symptoms: There are wrinkles, rough as the waves on the surface of the paint film.
- Paints are not uniformly thick, thin, wrinkled paint is often seen in places that are too thick.
- The paint is too thick.
- When spraying a lot of paint, but less wind.
- The paint must be uniform, the paint film must be evenly distributed.
- Recalculate the viscosity according to supplier ratio.
- Adjust the amount of spray gun to reasonable.
5. The paint film is peeling off
Phenomenon: paint film peeling off the surface of the product
- The surface of the product is not well prepared, grease, water, dirt or old shaving paint is not clean.
- The wood itself is too much oil.
- Strongly curing agent.
- Paint does not use the correct solvent system.
- Dirty grit between layers.
- Mix the paint for too long.
- The phase system is not compatible with the paint
- Before painting, prepare the surface well.
- Use oil-based solvent before using oil-repellent.
- Phase by supplier ratio.
Must use solvent as directed by the supplier, so use a supplier paint.
- Should be thoroughly sanded between layers.
- Mixing paint must be used immediately, avoid to last more than 6h.
- Use the same color and paint.
6. The paint film is flowing.
Phenomenon: The paint film is melted on the surface
- Spray on the surface too thick.
- The paint is too thin.
- When spraying paint to spray too close to the product.
- have to paint the appropriate thickness.
- The paint should be applied in accordance with the supplier, check the viscosity before painting.
- Keep the distance between the spray gun and the product sprayed (20 -> 25cm).
7. The paint film is rough or granulated (lacquered)
Upper: The paint film is evenly applied on the surface
- When the product is wet, the paint particles are often scratched on the surface.
- The paint environment, the product before the surface is not clean clean dust.
- Gun distance is too far.
- When painting the product, the last pad should be painted from the inside out so that it does not pile up on the painted surface.
- Cleaning the paint room and the product before applying the paint.
- Adjust the spray distance from the right technique: 20 -> 25cm.
8. The paint film is dusty.
Symptoms: The paint film gets dirt on the surface
- The paint environment, the paint room is not closed, many natural air flow from the outside.
- Sanding in the paint room close to where sprayed face.
- The paint room must be clean, the paint room should be sealed, avoid the natural air from blowing in.
- The top coat must be separated from the sanding.
9. The film is wet (not dry or dry).
Symptoms: The paint film gets wet
- When using PU spray,
- Curing agent does not guarantee quality or expiry date.
- Use weak solvent, insoluble solid.
- Use curing agent paint as the ratio of the supplier.
- Check the shelf life before preparation, storage container closed after use.
- Use the same solvent or the same supplier.
10. The paint film is colorless.
Symptoms: The paint film is sprayed on the surface
- When applying stain-free paint, the coating is applied to the surface.
- In the compressed air there are many oils, lubricants are not cleaned.
- For wood using dipping method.
- In order for the stain to dry before applying the overcoat, do not paint more than one coat at a time.
- Compressed air must be filtered out of the oil filter of the compressor.
- Use of colored poultry
11. Orange peel surface
Symptoms: The surface is not flat, convex as orange peel
- The solvent evaporates too quickly as the paint film does not have enough time to stretch the face
- Excessive spraying
- Technical issues when spraying and adjusting air injection too much, distance too far
- The workshop is too hot, too dry
- Use a spray gun to dry the surface, paint is not spread enough
- The paint is too thick, or too thick
- The paint does not stir well and the paint has not been dissolved completely when applied
- The spray gun must always be in good condition, used properly and adjusted spray gun.
- Improve the temperature in the paint environment.
- Use the correct diluent to paint.
- Adequate adhesion of the appropriate paint, too high or too low are not good.
- Before applying paint, the paint should be stirred well.
- Avoid heavy wind at the paint.
- Choose a good flowing paint
Here are the most common mistakes in pu coating technique and how to fix it. Paints opecpaint will continue to update the error if you have more questions as well as instructions to fix. If you have any difficulties please contact 0906 419 397 (Mr.Son_Tuc technical department) or send information through the website: opecpaint.com.vn, our technical team will help you. Wish you make the perfect product!