question :
Putty feels heavy
During the construction of putty, some people will encounter the situation that the hand feels heavy. What is the specific reason? How can it be improved?
Common reasons why putty feels heavy are:
1. Improper use of the viscosity model of cellulose ether:
In this case, the viscosity of cellulose ether is generally too high, and the putty made will feel heavy during the scraping process;
Another reason is that during construction in summer, the use of hydroxypropyl methylcellulose ether with poor high temperature resistance may cause the putty to lose viscosity, which will affect the construction feel.
2. Wrong ratio or fineness of powder:
Generally, there are too many inorganic gelling materials, or the fineness of the filler selected is too fine, which is prone to sticking to the knife;
It is also possible that in order to reduce costs, no or less additives to improve the hand feel are added, such as starch ethers and thixotropic lubricants.
Ways to improve 1
Appropriate raw material ratio and fineness selection
The fineness of the overall raw material can be controlled at 150-200 mesh, and the fineness of the filler can generally be 325 mesh, not too fine;
The amount of powdered polyvinyl alcohol shall not exceed 6%;
It is also necessary to learn to reduce the amount of inorganic cementitious materials. Generally, it is enough to control the cement at 28%-32%, and use additives to fully develop its performance.
Improvement method 2
Choose the right cellulose ether
Generally, we recommend hydroxyethyl methyl cellulose ether with better performance, which has better high temperature resistance and can be well adapted to summer construction and reduce winter and summer exchange costs;
The key is to choose a cellulose ether with a suitable viscosity. Generally, cellulose ether with a viscosity of 80,000 to 100,000 is enough for putty powder, but the amount of cellulose ether added must be determined through reasonable construction experiments!
Ways to improve 3
Add additives to improve hand feel
Finally, we can consider adding starch ether or thixotropic lubricant (bentonite) to improve the feel of the mortar;
Remember: the combination of scientific formula is the key to solve the problem!