Detailed explanation of the core construction process for the strongest putty powder - HPMC

HPMC powder is one of our best-selling products, offering low prices and high quality. It can be used as a thickening and water-retaining agent in building putties. Shijiazhuang Cellulose Co., Ltd. is a cellulose manufacturer from China and can provide you with a sufficient supply.

The core principle of this process is: "Seventy percent depends on the base layer, and thirty percent depends on the plastering and scraping." Any process that neglects the preparation of the base layer is incomplete.

Phase One: Thorough Preparation and Base Treatment (Foundation Stage)

1. Material Selection is Fundamental:

Putty Powder:  It is essential to choose water-resistant putty powder that meets national standards. High-quality water-resistant putty has high strength and good water resistance, preventing future problems such as dampness, peeling, and powdering. It is the material basis for the "strongest" process.

Supporting materials: Use the manufacturer's specified anti-alkali primer. Do not arbitrarily add glue, talcum powder, etc., to the putty, as this will completely destroy the product's performance.

2. Substrate Treatment: "Surgical-grade" cleaning:

Inspection and removal: Thoroughly inspect the original wall surface. All hollows, cracks, and loose old coatings must be removed down to the solid substrate. Any mold or oil stains on the old wall surface must be completely removed.

Cleaning: Use a wire brush or scraper to remove dust, release agents, etc., and then clean with a high-pressure water gun or damp cloth to ensure that the substrate is free of any contaminants that may affect adhesion.

Repair: For cracks, holes, and wire grooves, first fill them with jointing plaster. Larger defects need to be repaired and leveled with cement mortar. All joints (such as gypsum board joints) should be covered with anti-cracking tape or mesh fabric.

3. Sealing and Strengthening:

Applying wall primer (interface agent): Apply a layer of wall primer evenly to the clean, solid substrate. It seals loose dust on the substrate, improves the hardness of the substrate, and enhances the adhesion between the putty and the wall, preventing hollowing and delamination. The next step can only be performed after the wall primer is completely dry (transparent).

Phase Two: Precision Construction and Process Control (Core Phase)

1. Precise Mixing:

Strictly follow the powder-to-water ratio specified in the product instructions and mix thoroughly using an electric mixer. After mixing, let it stand for 5-10 minutes (curing), then stir gently again before use. The prepared putty should be used within the specified time (usually 1-2 hours).  Never add water to dried putty and reuse it.

2. Base Layer Leveling (Key Step):

Using a large trowel: The main purpose of the first coat of putty is leveling. Use an extended trowel longer than 60 cm to apply the putty, leveling out large uneven areas on the wall as much as possible in one go.

Thickness control: The thickness of a single application should not exceed 2mm. If the wall is very uneven, leveling should be done in multiple layers, prioritizing thin layers over thick ones. Excessive thickness can easily lead to cracking and slow drying.

3. Fine Application and Finishing:

Second coat of putty: After the first coat of putty is completely dry (usually 24-48 hours, depending on the climate), apply the second coat. This coat focuses on further fine leveling and correcting any imperfections from the first coat.

Finishing process: After applying the second coat of putty, when the putty layer is surface-dry but not completely dry (about 70-80% dry, not sticky to the touch but still slightly damp), use a stainless steel trowel or a clean large trowel, dipped in a small amount of water, to lightly press and smooth the surface in a vertical or consistent direction. This step significantly reduces the difficulty of sanding and improves the density and smoothness of the surface.

4. Corner Treatment:

Outside corners: A dedicated aluminum alloy corner bead must be used, embedded in the putty, to ensure the corner line is straight, strong, and impact-resistant.

Inside corners: Carefully trim with an inside corner trowel to ensure clear and straight lines.

Phase Three: Sanding and Final Inspection (Perfect Completion)

1. Scientific Sanding:

Timing:  Perform sanding only after the final coat of putty is completely dry (internal moisture content meets standards). Sanding before complete drying will cause the sandpaper to stick and damage the surface.

Tools: Use a high-brightness light bulb or professional sanding light to illuminate the wall from the side, revealing shadows. First, use coarser sandpaper (such as 240 grit) to address obvious protrusions, then use finer sandpaper (such as 360 grit or higher) for fine sanding.

Method: Use a long-handled sanding tool and perform large-area, even circular motions to avoid over-sanding in any one area. After sanding, thoroughly remove dust from the wall surface using a feather duster or hairdryer.

2. Final Acceptance Standards:

Flatness: Check with a 2-meter straightedge and wedge gauge; the wall flatness error should be ≤2mm. There should be no significant wavy shadows when illuminated from the side.

Verticality: Check with an infrared level or 2-meter straightedge; the verticality error of corners should be ≤2mm.

Surface Quality: No sanding marks, cracks, bubbles, or powdering. The surface should feel firm and smooth to the touch, without roughness.

Moisture Content: The moisture content of the wall base should be below 10% before applying the primer.

The "Strongest" Principle Throughout the Process:

Thorough Drying Principle: Every step must be performed only after the materials from the previous step have completely dried. This is the most important principle to prevent cracking and blistering.

Side Lighting Inspection: Whether it's troweling or sanding, side lighting must be used to check for flatness. This acts as a "revealing mirror" to uncover any problems.

Environmental Maintenance: During construction and curing, the environment should be well-ventilated, avoiding direct sunlight and strong drafts to prevent the putty layer from drying out too quickly. During winter construction, the room temperature must be maintained above 5°C.