4. Is it necessary to use interface agent before spraying?

Interface agents are usually used on concrete surfaces. Because the concrete surface is too smooth. By using an interface agent, the surface of the base layer can be roughened. It can increase the adhesion of mortar to the base layer. Avoid plaster layers with hollow shells. Before spraying, it is generally necessary to use an interface agent to treat the wall.
The interface agent is emulsion type, which can be applied with a roller or a brush. There is also a dry powder type, first add water to mix the dry powder. Then use a roller to brush or spray it onto the wall.
Different wall materials need to be treated with different interface agents, so that the effect is better. For walls such as porous concrete brick walls, cement-based hollow brick walls, and red brick walls, light-weight block interface agents can be used. Concrete and precast concrete walls, concrete interface agent can be used. For gypsum-based insulation boards, a gypsum board interface agent can be used.

5. How to make the gypsum mortar spray neither block nor sag?

The main reason for pipe blockage is that the mortar gradation is unreasonable, and there are large particles that get stuck and block the pipe. The consistency value of the mortar is too small and the fluidity is poor. No pre-cleaning of pipes. Unskilled operation, such as only opening the pumping valve but not the air pressure valve, resulting in blocked pipes. The main reason for the sagging phenomenon is that the viscosity of the mortar is too low and the adhesion to the base layer is not enough.
Therefore, prevent the machine-sprayed gypsum mortar from blocking and hanging. First of all, it is necessary to correctly select the machine sprayed gypsum mortar. Because the reliable quality gypsum mortar not only has a reasonable gradation, but also mixes compound additives such as water retaining agent and pumping agent. The pumpability, viscosity and fluidity can meet the requirements of machine spraying.
Secondly, adjust the water volume to be constant according to the instructions of the machine sprayed mortar, and the machine will automatically mix the materials. Neither too much nor too little water. Too much will cause the mortar to hang easily, and too little will cause the mortar spraying to be not smooth, and it will be difficult to level the mortar later.
Third, correctly grasp the operation of machine spraying equipment, and clean the pipeline after each construction.

6. How to level to get better flatness?

Dot punching is for consistent spraying thickness and also for leveling. In order to obtain better verticality and flatness. First of all, we must grasp the leveling time. Generally, when a wall is sprayed to the second half, it starts to be leveled. This ensures that the mortar is relatively fresh and easy to level.
Secondly, you must master the leveling method: hold the H scraping ruler as far as possible to widen the distance between your hands to avoid uneven strength and uneven thickness. The height of the two closest ribs should be used as the standard, and leveling should be carried out in both left and right and up and down directions. Don’t just level from one direction. When horizontally leveling from bottom to top, start from the floor position, and don’t bring too much force. When checking the flatness, use the H scraper to check back and forth horizontally and vertically and make corrections.
Several questions about machine-sprayed gypsum mortar
Several questions about machine-sprayed gypsum mortar (3)