- 1. Chromatic aberration
Reasons
- 1. 1 The putty powder itself is a semi-finished product. The instability of raw materials is one of the main causes of color difference. The quality of the ore powder mined from different mining areas will be varied and if no blending, there will be color differs from different batches.
- 1.2 Some suppliers mix low-grade raw materials, when the purchased quantity is large, it is impossible to check every batch, which leads to low-quality products mixed in the production and resulting in color difference.
- 1.3 The chromatic aberration is caused by mixing different grades of raw materials or scraping different brands of products on the same wall due to the mistakes of the production personnel.
Solutions
- The color difference is generally not a matter of formula, when it happens, it is recommended to scrape a piece of putty powder or paint with no color difference.
- All personnel involved in production and construction should strictly follow relevant standards for production and construction to avoid man-made quality problems.
- 2. Powder removal
Reasons
- 2.1 Construction: the painter used a scraper to dry the wall several times during the last finishing process, the surface of the surface will be slightly peeled. After drying, it will be powder removal.
- Man-made: When the putty is not dry, it encounters dust adhering to the wall surface, such as cutting operation, strong wind or cleaning the floor, etc., leading the false powder removal.
- 2.2 Production: wrong formula, or due to the unloading of the machine and equipment, which caused the formula to be unstable.
Solutions
- The construction workers should pay attention to the surface humidity of thewallputty when doing the last non-painting layer. If it is too dry, it will cause powder peeling. And it’s enough to smooth the knife marks when finishing, not suitable for multiple dry scraping.
- If there is false powder removal caused by the dust attached to the wall, just removed the dust with a feather bomb after the completed decoration, or wipe it with clean cloth.
- If there is quick-drying powder removal, it’s need to identify whether it is caused by the formula by technical dept..
- 3. Mouldy
Reason
3.1 If the raw materials are mixture of sea sand and cement, which own high acidity and alkalinity, and then acid-base reactions happen at the baseboards or leaking places on the wall, further causing the wall putty with problems of hairy, moldy, hollow, and shedding.
Solution
Remove the moldy and hollow putty, and clean it with water. And if there are leaks or damp wall putty, repair and stop the water source in time, and then scrape the alkali-resistant putty again after the walls are dry fully.
- 4. Drying quickly
Reason
- 4.1 Due to the high temperature in summer, the water evaporates quickly during the operation of scraping wall putty, which usually occurs on the second stage of the construction.
- 4.2 Cellulose ether’s water retention rate is low, qualified cellulose ether should own the capacity of keeping mortar at least two hours before scrapping.
Solutions
- During construction, the temperature should not be higher than 35℃. The second stageof wallputty should not be scraped too thin.
- If there is a quick-drying phenomenon, it’s need to check and identify whether it’s caused by the formula.
- If quick-drying happens, it is recommended that the construction should be completed for about 2 hours afterthe previous constructionwhen the surface is dry, this way helps reduce the quick-drying.
- Choose high quality cellulose ether with good water retention rate.Landercoll HPMC K100 and MHEC EM100, with middle viscosity, are highly recommend for wall putty, which own good performance of water retention and workability even in summer.
- 5. Pinhole
Reasons
- 5.1 It is normal for pinholes to appear when scraping the first layer, that’s because the wall putty layer is very thick and not easy to be flattened. Pinholes in the second and third layers are appear at uneven areas on the wall, that’s because more materials existand dry slowly, it is more difficult for the scraper to compact the putty in the concave areas.
- 5.2 Insufficient light during construction will cause the construction personnel to ignore some small pinholes on the wall, and can’t flatten them in time.
Solutions
- The uneven wall surface should be filled to flat as much as possible during the first layer, this is conducive to scraping the second and third layer and the generation of pinholes will be reduced.
- Pay attention to light during construction. In case of insufficient light in bad weather or when the light turns from bright to dark in the evening, construction should be carried out with the help of lighting equipment to avoid man-made pinhole problems caused by construction errors.
- Putty powder with higher viscosity or slow drying will also produce some pinholes, so attention should be paid to the rationality of the formula.
- 6. Delamination
Reasons
- 6.1 The type of slow-drying wall putty own the trait that the firstlayer of putty will increase its hardness along with time and absorption moisture from air. The interval time between the first and last layers is long. When the last layer is completed, the grinding will begin. The outer layer is looser and easier to polish, meanwhile the firstone is placed for a long time and harder to polish, which will form a similar delamination phenomenon finally.
- 6.2 When scrap the last layer of wall putty, the hardness will be different between surface film and inner layer due to the too big pressure and long interval time. The inner layer is loose and easy to be ground, while the surface film own higher hardness and is not easy to be ground, which will cause delamination.
Solutions
- After the firstlayer construction is completed, if interval time is too long due to some reasons such as rainy season, it is recommended to scrape two coats of wall putty in the next step of construction.
- When scraping the last layer of putty, not to press too hard, but just faltten the pinholes and knife marks on the surface. In case of wet weather or rainy season, work should be suspended.
- 7. Hard to polish
Reasons
- 7.1 It is more difficult to polish a wall when it’s too solid or polished during construction, which with increased density and stronger hardness of the wall putty layer.
- 7.2 The slow-drying wall putty will achieve the best hardness after one month. If it encounters water, such as wet weather, rainy season, wall seepage, etc., it will accelerate hardening and make it more difficult to polish, and the polished layer is rougher.
- 7.3 Different formulas of wall putty are mixed together, or the dosage of formula is adjusted incorrectly, so that the hardness of the wall putty after scraping is higher.
Solutions
If the wall is too solid and hard to polish, it should be roughed with 150# sandpaper first and then 400# sandpaper to modify the pattern or scrape two more times before polishing.
- 8. Cracks
Reasons
- 8.1 External factors including thermal expansion and contraction, earthquakes, subsidence of foundations.
- Incorrect proportion of mortar in the curtain wall will shrink and cause cracking drying.
Solutions
- External forces are uncontrollable, it is difficult to prevent and control.
- The scraping process should be carried out after the wall drying fully.