Guidelines for PU Spraying Application

We are a manufacturer of polyurethane spraying machines, providing one-stop service. Whether you need spraying machine equipment, raw materials, accessories, or other supporting products, we can handle it all for you. We also have our own R&D team that can customize raw materials to your specifications. Our customers are particularly concerned about precautions during the application process, so we have compiled this article to help you have a smoother application experience.

Preparation before construction

Environmental preparation for polyurethane spraying: The ambient temperature for spraying should be 10-40℃, the wind speed should not exceed 5m/s, and the relative humidity should be less than 80%. Construction should not be carried out in rainy weather.

Polyurethane spraying construction wall preparation

• Clean the wall surface of laitance, oil stains, and dust; if the base layer is uneven, it needs to be leveled with mortar, and any protrusions exceeding 10mm should be removed, and any defects should be repaired with cement mortar.
• Concealed pipelines, junction boxes, and embedded parts need to be installed in advance, and the thickness of the insulation layer should be reserved.
• Before construction, cover the areas that will not be sprayed, such as doors and windows, with plastic film or cardboard; it is recommended to install the roof door and window frames after the spraying is completed.
• temperature for the sprayed surface is 30–40°C ; too low a temperature will affect the foaming effect, while a warm substrate can enhance the foaming quality.
• Polyurethane is a moisture-curing foam and should be sprayed onto a slightly damp surface. The higher the humidity, the faster it cures.

Preparation of polyurethane spraying equipment: After the spraying equipment arrives on site, it should be run empty to check whether it is working properly.

Construction process control

Polyurethane spraying techniques

• Spraying should begin from the edge , and after foaming, spray along the edge of the foam.
• The thickness of the first coat should be controlled at around 10mm.
• The thickness of the second coat should be controlled within 15mm until it reaches the thickness required by the design.
• After the polyurethane rigid foam insulation layer is sprayed, the thickness of the insulation layer should be checked as required, and quality inspection should be carried out and inspection records should be made according to the inspection batch requirements.
• the polyurethane insulation layer is sprayed, use a planer, hand saw, or other tools to clean, trim, cover, and protect the parts, as well as any protruding parts that exceed the specified thickness by 1 cm.

Polyurethane spraying quality control :

The spray gun should be kept as perpendicular to the wall as possible, with a distance of about 500mm. During spraying, the surface of the foam should be smooth, without obvious shrinkage or peeling. Its appearance is slightly yellowish, with uniform and fine closed-cell structure, and its surface is not loose, brittle, or soft.

Post-construction control

• Uncured foam can be cleaned with a cleaning agent. Cured foam should be removed mechanically, such as by sanding or cutting.
• Cured polyurethane foam will turn yellow when exposed to ultraviolet light, so it is recommended to coat the surface of the cured polyurethane foam with other materials (cement mortar, paint, etc.).
• After using the spray gun of the polyurethane spraying equipment, please clean it immediately with a special cleaning agent.

Safety protection and storage

Personal protective equipment (PPE ): Professional protective masks, gloves, goggles, and protective clothing must be worn during operations . We can provide you with the necessary protective equipment.

Environmental requirements : Ensure good ventilation during the spraying process. It is crucial to note that smoking is strictly prohibited at the construction site.

Storage : Avoid direct sunlight and store in a cool, dry place at a temperature not exceeding 50 °C. Do not place near open flames or with flammable or explosive materials.

Transportation: Severe jolting and collisions are strictly prohibited during transportation. The container must not be inverted or placed on its side.

Waste disposal: Empty cans after use must not be burned or punctured and should be handed over to qualified recycling points for disposal.

Skin and clothing contact: Uncured foam is highly sticky; avoid contact with clothing. If it gets into eyes or on skin, rinse immediately with plenty of water. If discomfort persists, seek medical attention immediately.

We hope these points will help you navigate construction more smoothly and efficiently, avoid common problems, and provide a more reliable guarantee for project quality. If you need further support regarding equipment, materials, or construction techniques, our team is always ready to provide you with professional one-stop service.