Causes of putty powder cracking and shedding and treatment methods


Release time:

2020-10-23

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Causes of putty powder cracking and shedding and treatment methods
 
putty cracking
Phenomenon: putty construction after a period of time, the surface cracking.
Cause:
1, the base is not completely dry on the construction, the construction requirements of the base moisture content ≤ 10%.
2. The bottom putty is not completely dried, and the surface layer is dried first, while the inner layer is still in the process of drying, resulting in different degrees of dry shrinkage between the layers and easy cracking.
3, grass-roots treatment, joint and fill the material is not completely dry, above the application of strong hardness of the wall putty, easy to cause cracking;
4. The construction is too thick, the internal drying is slow, the surface drying speed is faster, and it is easy to cause cracking.
Solution:
1, has cracked putty, need to eradicate, if the crack is not too big, can also use flexible putty for the first construction, and then according to the standard construction method of construction.
2, each construction should not be too thick, the two construction time interval must be greater than 4 hours, the front putty completely dry, before the back scraping.
 
Putty shedding
Phenomenon: refers to the poor bond strength between the putty and the grass-roots level, directly from the grass-roots fall off.
Cause:
1, the old wall is very smooth (such as toughened putty, polyurethane and other oily paint), putty powder and its surface adhesion fastness is poor.
2, the new wall using template pouring, the surface is smooth and contains a lot of release agent (waste oil or silicone).
3. For non-mortar substrates such as wooden substrates and metal substrates (such as plywood, pentaplywood, particleboard, solid wood, etc.), putty is directly applied to the surface. Due to the different swell-shrinkage ratios and the strong water absorption rate of such products, rigid interior wall putty cannot deform with it, and will generally fall off after 3 months.
4, putty exceeds the shelf life, the bond strength is reduced.
Solution:
1. Remove the shedding layer and deal with it according to the following conditions;
2. Grind the old wall to increase the surface roughness, and then use the interface agent (10% environmental protection glue or interface agent);
3, with degreasing cleaning agent to remove the surface of the release agent or other grease components, and then apply the putty.
4, the use of two-component or special plywood putty for construction.
5, marble, mosaic, ceramic tile and other exterior wall surface, please use exterior wall renovation putty backing.
6. Use within the shelf life of putty.
 

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