Recently, we have adjusted ordinary plastering mortar for several construction sites. The problem with these sites is relatively uniform, which is the sticking of plastering mortar to the knife. We have summarized several reasons that cause knife sticking, all of which are dry goods. Remember to like and collect them.
Firstly, the sand grading is unreasonable. There is a gap in sand grading, and a good grading is filled with fine sand to fill the gaps in coarse sand, and filled with adhesive slurry to fill the gaps in fine sand. Once the grading is unreasonable, it is easy to cause a heavy hand feel.
Secondly, sand has a high mud content and mortar has a high content of stone powder. When the old master used to plaster walls, he often said to add water when it was thick and powder when it was thin. However, the specific surface area of stone powder is large, and it adsorbs a lot of water, but it is not active. This can cause the mortar to be thick and weak, so it is crucial to maintain a reasonable proportion of powder.
Thirdly, high bulk density. Some people believe that air entraining agents are harmful but not beneficial, so they strongly reject them. If air entraining agents are not added, it will result in high bulk density, heavy hand feel, and difficulty in scraping the plaster mortar. In fact, the air entraining agent is a panacea, and a very low dosage can effectively change the construction feel. However, it is important to note that the dosage should not be too high, otherwise it will have a significant impact on the strength.
Fourth, the amount of cellulose ether added. It's winter now, and for winter construction, the amount of cellulose ether added can be appropriately reduced. If the addition amount is still the same as in summer, it will cause the mortar to become thick, stick to the knife, and difficult to scrape.
The above are the main reasons for the sticking of the plastering mortar knife. If you also encounter the same problem, you can compare and check it yourself. If there are other problems, please feel free to contact us and we can help you adjust them.