Causes of Foaming and Yellowing in Putty Powder and Corresponding Remedies
Release Time:
2020-10-19
Source:
Causes of Foaming and Yellowing in Putty Powder and Corresponding Remedies
Putty bubbling: Bubbles form during application, and the putty surface may bubble after a period of time.
Causes:
1. The substrate is excessively rough, and the plastering is being applied too quickly;
2. The putty layer applied in a single coat is excessively thick, exceeding 2.0 mm;
3. The substrate has excessive moisture content, coupled with a density that is either too high or too low. Due to its abundant porosity and the high moisture content of the putty, the material becomes impermeable, trapping air within the pores and cavities, which is difficult to dissipate.
4. Cracking and blistering that appear on the surface only after a period of construction are primarily caused by uneven mixing, resulting in powdered particles in the slurry that do not have sufficient time to dissolve. After application, these particles absorb large amounts of water, swell, and ultimately lead to cracking and blistering.
Solution:
1. For putty surfaces with extensive blistering, use a putty knife to carefully puncture the small blisters and then apply a suitable putty to re-spread over the blistered area.
2. After the putty has been thoroughly mixed, allow it to stand for about 10 minutes, then remix it with an electric mixer before applying it to the wall.
3. If bubbling occurs in the second or final finish coat during construction, it shall be promptly broken and eliminated with a scraper before the water marks have fully disappeared, to ensure that no air bubbles remain on the putty surface.
4. For particularly rough wall surfaces, it is generally advisable to use a coarse-textured primer or putty whenever possible.
5. In conditions where the wall surface is excessively dry or exposed to strong winds and intense sunlight, first moisten the wall as thoroughly as possible with clean water. Once the surface is free of standing water, proceed with applying the putty layer.
Yellowing of putty: Refers to the phenomenon where, shortly after putty application is completed, localized or widespread yellowing occurs.
Causes:
This phenomenon primarily occurs on old interior wall surfaces, where the old putty contains a large amount of PVA adhesive. Over time, the adhesive ages and decomposes, releasing unsaturated acids. These unsaturated acids then react with calcium ions in the putty to form corresponding yellow calcium salts.
Solution:
1. Apply two coats of eco-friendly adhesive by rolling, and after it is completely dry, proceed with applying interior wall putty.
2. Apply two coats of sealing primer by rolling, and after it is completely dry, apply putty.
3. Apply only paste-type putty, or use board-specific putty for application.
