Fireproof Coating Application Process: Say Goodbye to Rework!

1. Spraying and Trowel Application Processes

2.1 Main Application Equipment: Air compressor, gravity-feed spray gun, paint spray gun, air hose, etc.

2.2 Key Points for Spray Application:

(1) The spray gun should preferably be a gravity-feed type for coatings, with a nozzle aperture adjustment range typically between 6-10mm (adjustable nozzle guns are recommended). The air pressure should be maintained at 0.4-0.6 MPa. The distance between the spray gun nozzle and the work surface should be appropriate, usually controlled at 25-30 cm. The direction of the spray gun should be roughly perpendicular to the substrate surface, and its movement path should be parallel to the surface, avoiding arcing swings to prevent a thick center and thin edges on the coating. During operation, start moving the gun before opening the air valve, and close the air valve before stopping the gun movement at the end of a pass. This avoids excessive thickness at the end of each coat, ensuring overall uniformity and a neat appearance.

(2) Spraying should be completed in 2-5 passes. The first pass aims to cover the steel surface. The thickness of each subsequent spray pass should be controlled between 5-10 mm, with around 7 mm recommended. Typically, one spray pass can be completed per day.

(3) When dealing with external corners of members, first spray vertically along the edge from top to bottom or left to right, perpendicular to the surface, then spray horizontally. For internal corners, avoid spraying directly into the corner. Instead, spray vertically once from each side of the corner from top to bottom, then spray horizontally. During vertical spraying near the corner apex, keep the gun nozzle slightly farther away, allowing the sprayed coating mist to converge naturally at the apex, preventing sagging. When spraying the underside of beams, the operator should maintain an appropriate distance, and the gun's tilt angle should not be excessive to reduce overspray and ensure smooth material flow.

(4) Maintain a constant movement speed during spraying; avoid dwelling too long in one spot, which can cause material buildup or sagging. Material preparation and feeding into the pump should be continuous without interruption. Use a thickness gauge during application to check the coating thickness in real-time. Stop only after the design thickness is achieved. Necessary trimming is required after spraying; use a putty knife or similar tool to remove prominent protrusions, ensuring the coating surface is flat and uniform.

2.3 Main Tools for Trowel Application: Putty knife, trowel, and spreader.

(1) Key Points for Trowel Application: Trowel application typically uses a putty knife, trowel, or spreader. The key points are solid, flat, and smooth – meaning the fireproof coating layers should have tight contact and strong adhesion, and the surface should be level and smooth to reduce trimming work and achieve a smooth finish for the entire coating. Control the tilt angle of the troweling tool properly and apply force evenly.

(2) Brush Application Process and Technical Points: Preferably choose a brush with hog bristles, about 75-150mm wide, with uniform bristles that don't shed easily. To prevent bristle loss during brushing, first dip the brush into the coating, allowing it to penetrate to the bristle roots to secure them. Clean the brush promptly with water or solvent after use.

When brushing, first wet the brush with water or thinner and shake it dry, then dip it into the material. Don't dip the bristles too deeply into the coating. After dipping, scrape off excess coating on a mixing board or the edge of the bucket. Then brush onto the steel substrate in an orderly manner. The angle between the brush distributing the material and the surface being coated should be about 50°–70°. Brushing movements should be swift, and each brushed section should not be too wide to ensure that edges are not yet dry when connecting sections, avoiding visible lap marks.

Hebei Zhihe Fireproof Material Technology Co., Ltd., as a professional manufacturer of fireproof coatings, anticorrosion, and floor coatings, has been committed since its establishment to the R&D, production, sales, and application of fireproof coatings, anticorrosion, and floor products. Our product quality is guaranteed, with complete certificates and qualifications. We offer material-only purchases, or we can provide labor, materials, and acceptance handling. Free budgeting is available, and we can provide construction teams. One-stop service provides customers with peace of mind and convenience.