Proper Techniques for Using PU Foam Correctly

PU foam sealant is widely used in construction thanks to its ability to fill gaps, provide sound insulation, improve thermal insulation, and enhance waterproofing performance. When exposed to air, the foam expands and forms a firm layer that helps seal gaps and cracks in construction works.

Today, An Thai Khang’s PU foam product lines, including RV Foam, S-Foam Neo, and S-Foam 900g, are trusted by many contractors for their strong adhesion, stable expansion, and ease of application.

Understanding the correct techniques for using expanding foam helps improve construction efficiency and reduce material waste.

2. What is PU foam sealant?

PU foam sealant is a single-component polyurethane foam that expands automatically when it comes into contact with moisture in the air. After application, the foam expands and hardens into a layer that provides insulation and waterproofing.

PU expanding foam is commonly used for:

• filling wall gaps

• installing windows and doors

• soundproofing machine rooms

• sealing pipe openings

Because of these properties, PU foam for wall gap filling has become a popular solution in many construction projects.

3. Preparation before using expanding foam

3.1 Clean the surface

Before application, dust, dirt, and grease should be removed from the surface. A clean surface helps the foam adhere better and expand more evenly.

3.2 Prepare the necessary tools

The required tools include:

• a can of PU expanding foam

• a spray nozzle or foam gun

• protective gloves

• a cutting knife

Proper preparation makes the application process faster and more accurate.

4. Technical guide to using expanding foam

4.1 Shake the can well

Shake the can for about 30 to 60 seconds before use so that all components are mixed evenly.

4.2 Attach the nozzle or foam gun

Attach the spray nozzle or foam gun to the top of the can. During application, the can should be held at an angle of about 45 degrees.

4.3 Apply the foam into the gap

Only fill about 50% of the gap volume, as the foam will expand and fill the remaining space.

4.4 Wait for the foam to cure

The foam will begin to expand within a few minutes and becomes surface-dry after approximately 10 to 20 minutes, depending on environmental conditions.

4.5 Finish the surface

Once the foam has fully cured, any excess material can be trimmed off and painted over for a cleaner appearance.

5. Applying these techniques with An Thai Khang PU foam products

Each foam product has different expansion characteristics and adhesion properties, so the application method should be adjusted accordingly for the best results. Below are some technical guidelines for using An Thai Khang’s PU foam products.

5.1 RV Foam

RV Foam is a fast-expanding product with strong adhesion, making it suitable for narrow gaps and areas that require a tight seal.

When applying RV Foam, it is recommended to spray from the bottom upward so the foam expands evenly and fills the gap effectively. For narrow spaces around door and window frames, only a moderate amount should be applied because the foam will continue expanding after spraying.

Once the foam has dried, any excess material can be trimmed neatly with a knife.

5.2 S-Foam Neo

S-Foam Neo features stable expansion and fast drying, making it well suited for interior construction applications.

When using this product, the can should be shaken thoroughly before spraying, and the nozzle should be moved evenly along the length of the gap. This helps distribute the foam uniformly and reduces the risk of uneven expansion.

After the foam becomes surface-dry, it can be trimmed and refinished if necessary.

5.3 S-Foam 900g

S-Foam 900g is a high-capacity expanding foam with strong expansion performance, making it suitable for wide gaps or areas that require a larger amount of foam.

When applying this product, it is best to spray in thin layers rather than applying too much at once. This allows the foam to expand more steadily and helps prevent overflow.

During spraying, the nozzle should be moved slowly and evenly to ensure the foam covers the entire gap. After the foam hardens, the excess can be trimmed off for a neater finish.

6. Important notes when using expanding foam

When applying expanding foam, keep the following points in mind:

• work in a well-ventilated area

• avoid contact with skin and eyes

• do not use near open flames

• store the product in a dry place

7. Conclusion

Applying the correct techniques for using PU foam sealant helps make construction work faster and more effective. RV Foam, S-Foam Neo, and S-Foam 900g by An Thai Khang are suitable choices for a wide range of construction applications, including wall gap filling, door installation, and sound insulation.