Why does the thin place of lightweight gypsum take off the white powder？

[Allen]

Lightweight plaster has good strength in thick places and little strength in thin places. How can we make the thin place have better hardness?

 

[Roy]

It may be that the thin part loses water too fast, and the way to treat it is to increase the water retention rate.

 

[Cassie]

The thin part also depends on how light it is. If the thickness is 1mm, neither using an interface agent nor a water-retaining agent will not work. If you know it is thin, make it thicker. Putty will perform better than light plaster if it must be done very thinly.

 

[Scott Kaplan]

The water retention requirements are higher in thinner places, and the amount of cellulose ether added is different.

 

[Luis]

One is to shorten the final setting time, and the amount of retarder should be manageable, and the other is to improve water retention; if it is not possible, use an interface agent.

 

[Chanliss]

The best way is to increase the water retention performance and apply an interface agent, but the thinnest should be at least 3mm; otherwise, there will be a risk of whitening and powder loss no matter how you handle it. The powder has already fallen off; if you don’t want to shovel it, spray water directly and give the gypsum another time to hydrate.

 

[Alex]

The thin part also depends on how light it is. If the thickness is 1mm, neither using an interface agent nor a water-retaining agent will not work. If you know it is thin, make it thicker. Putty will perform better than light plaster if it must be done very thinly.

Indeed.

If it is too thin, it has nothing to do with the water-retaining agent but something to do with the cohesion/adhesion of the material itself.

The bond strength is apparent unless a tremendous amount of rubber powder is added.

 

[Shamil]

Water loses fast in thin places, and the gypsum has no water before it hardens, so it has no strength.
Two solutions,
1. Shorten the hardening time so that the gypsum hardens before the water is lost
2. Add water-retaining agents such as cellulose ether so that the water will not lose too quickly before the gypsum hardens