Common Questions and Answers ：
Epoxy Coating ：
1. Lump
Possible reasons:
1. Moist foundation or previous process not dry
2. Fast surface drying speed due to excessive high air temperature
3.Mechanical bubble caused by mixing or by coating during construction
Treatment methods:
1. Construction begins after ground dries and sealing treatment is made for surface
2. Choose proper time for construction
3. Construction begins several minutes later after mixing
4.Partial repair or re-painting after removal and strengthened foundation seal depends on bubble conditions
2. Blushing paint film without luster
Possible reasons:
1. Oiling and blushing is caused by absorption of water which is caused by curing due to high temperature and low humidity during construction.
2. Paint film wetted before curing time reached, or excessive amount of amine curing agent<
Treatment methods:
1.Avoid construction in rainy, high humidity and low temperature environment
2.Flushing with water is prohibited during curing period; even mixing and proper weighing when construction2）
3、Poor adhesive force, easy falling-off of paint film
Possible reasons:
1.Not clean ground with oil or water, or chalked
2.Soft foundation structure, stripping caused by contract and expansion of bottom layer
3.Surface is not easily polished and not penetrated due to dense and smooth ground structure
Treatment methods:
1.Remove impurities from ground, remove chalked ground and strengthen ground sealing
2.Carefully polish smooth ground, clean dust and coat bottom oil for sealing
3.Polish stone, ceramic tile and marble foundation that is unfavorable for construction
4. Shrunk hole
Possible reasons:
1.Oil, acid or alkali scale, and wax, etc. on foundation
2.Surface paint coated on wet bottom oil or moist foundation
3.Long time interval between the first and second procedure without polishing
4.Shrunk hole caused by settlement of dust on wet surface due to poor construction environment though no shrunk hole occurs during construction
Prevention methods:
1.Remove oil and wax impurities by cleaning ground with solvent before coating bottom oil
2.Ground shall be dry, and next process shall begin only after bottom oil is coated and cured
3.The second process shall only begin after the first process is coated and polished the other day. If the second process begins several days later due to certain reasons, it shall not begin until complete removal of floating dust.
4.Keep clean internal and external environment for construction
5. Orange peel
Possible reasons:
1. Too fast volatilization of solvent
2. Poor leveling
3. Too high temperature of construction
4. Orange peel easily formed in the area near wall in case of large difference between air temperature and surface temperature under low temperature condition
Treatment methods:
1. Adjust drying speed and choose solvent with high boiling point
2. Add a small amount of thinner
3. Avoid construction in high temperature environment and use equipment for ventilation and cooling.
4. Construction in an environment below 50C is not recommended
6. Abnormal particle
Possible reasons:
1. Ground surface not clean
2. Caused by floating dust in the air after polishing
3. Coarse particles and impurities in additives
Treatment methods:
1. Clean ground surface
2. Treat ground after it is polished and floating dusts in the air fall down, and prevent outdoor dusts from entering indoors
3. Added powder must be filtered
7. Brush marks
Possible reasons:
1. Excessive high viscosity
2. Excessive fast dry
Treatment methods:
1. Add thinner properly to decrease viscosity
2. Add solvent with high boiling point to for proper adjustment
8. Flooding and floating
Possible reasons:
1. Flooding caused due to low roller coating viscosity
2. Flooding caused due to high spray coating viscosity
Treatment methods:
1. Control addition of thinner during construction
9. Poor hiding power
Possible reasons:
1. Coating is excessively thinned
2. Tint color causes poor hiding power of color itself
Treatment methods:
1. Increase coating times to increase hiding power
2. Adjust color of preparation
10. Color difference
Possible reasons:
1. Color difference is caused due to addition of unequal amount of added powder for each group and different colors
2. Time interval between each group of coating when construction is long
3. Main ingredient does not belong to the same batch
Treatment methods:
1. Strictly control quality of added powder and weigh accurately
2. Pay attention to continual work without interval
3. Color difference is inevitable for main ingredient (color part) not the same batch and full consideration should be given when conducting bedget
11、Hunching up due to partial or whole dissolution of bottom coating after coating from bottom
Possible reasons:
1. Not matching of bottom layer with surface layer coating (such as NC as bottom, PU as surface), primer layer too thick
2. Too short time interval between bottom and surface coating, bottom layer not properly treated (such as loose bottom material); bottom layer excessively hardened
Treatment methods:
1. Bottom layer coating should match with surface layer coating
2. Primer layer should not exceed 30um for one time of coating
3. Choose the same type of coating, and coat surface coating after bottom layer dries practically. Bottom coating should be fully hardened
4. Filling agent remained base material hole should be cleaned
12. When coating vertical or oblique surface of sagging and drooping coating, viscosity of coating and drying is not balanced, coating skill is not good, paint film droops or salivates (partial or full) in the form of long column or curtain, especially on edge, with flow marks
Possible reasons:
1. Excessive addition of thinner, low viscosity of coating when construction, paint film sprayed too thick or time interval too short
2. Short distance of spray, slow moving speed, too much oil sprayed, uneven air pressure of spray
3. Coating lacking thixotropy
4. Coated surface too smooth
5. Slow volatilization of solvent in coating
6. Coating environment full of solvent air
7. It is more likely to occur in too low temperature environment, temperature difference between coating and coated object in coating room is large
8. Too much pigments in coating not evenly mixed when preparing paint.
Treatment methods:
1. Adjust proper viscosity, and spraying thickness in one time should not exceed 30um
2. Use caliber spray board according to practical conditions, generally 1.5-2mm. Keep air compressor with stable air pressure when construction, spray distance is 150-3000mm, spray gun speed is 30-50cm/sec, control output for spray and master proper time interval for re-spray
3. Pay attention to proportion of pigment to provide proper thixotropy of coating
4. Keep proper roughness for surface of coated object, carefully polish for re-spray of each layer
5. Reduce temperature difference between coating and coated object in coating room by strengthening air exchange equipment. Temperature of coating room is 15-30℃
6. Coating should be fully mixed even many times during construction |
