What are the precautions for applying adhesive to plywood?

Precautions for applying adhesive  

Recommended white glue manufacturers:  

1. Construction conditions  

The suitable bonding temperature for all-purpose adhesive is 25±5℃, and the humidity is 55-75%. It must be thoroughly stirred before use. All-purpose adhesive contains volatile solvents; therefore, ensure good ventilation during application and avoid proximity to open flames or high temperatures. Generally, all-purpose adhesive may gel in winter when the temperature is below 5℃, affecting its use. In this case, soaking the adhesive container in hot water (30℃-50℃) for 20 minutes will restore its original shape and performance, allowing it to continue to be used.  

2. Surface requirements  

Before using all-purpose adhesive, it is essential to properly treat the surfaces to be bonded. This includes degreasing, removing rust, removing moisture, and sanding to ensure the surface is clean, dry, and firmly bonded. For degreasing and cleaning, use quick-drying solvents such as 120# gasoline, toluene, or ethyl acetate, and allow to dry. Sanding is typically done lightly with 0# or 1# sandpaper. Suitable for bonding plywood, flooring, bamboo, or other wood materials.

When applying adhesive, the moisture content of the object to be bonded must be below 8%. If it is above 8%, the object should be dried or baked before applying the adhesive.  

3. Apply glue  

For most materials, one coat of adhesive is sufficient. For porous materials, two to three coats are required, and each coat must be applied only after the solvent from the previous coat has completely evaporated. Do not rush the process.  

To prevent air pockets in the adhesive layer, apply the adhesive in the same direction to facilitate air expulsion, but be careful not to apply it too quickly. Generally, the thinner the adhesive layer, the fewer defects, the less shrinkage, and the higher the bond strength. A thin adhesive layer is preferable to a thick one; an excessively thick layer will result in defects such as incomplete drying, poor adhesion, and bubbling. Therefore, while ensuring sufficient adhesive, the adhesive layer should be as thin as possible. The adhesive layer thickness should generally be controlled between 0.08 and 0.15 mm, which corresponds to an adhesive dosage of 250-350 g/m².  

4. Let it air dry  

The purpose of allowing the adhesive to dry completely is to allow the solvent to evaporate, increase viscosity, and promote curing. After applying the adhesive, the solvent must be allowed to evaporate completely; do not bond immediately, as this will cause the adhesive layer to become sticky or form bubbles, leading to a decrease in bonding quality. The drying time is generally 5-15 minutes at 25℃. When the adhesive layer becomes a dry film (not sticky to the touch), it should be aligned and bonded immediately; the drying time should not be too long, otherwise the adhesive layer will lose its tackiness, affecting the bonding strength.  

5. Adhesive pressing  

Super glue has strong adhesion, so be sure to time it precisely and align it in one go; do not move it back and forth. After bonding, use pressing, hammering, or rolling to remove air bubbles, compact the adhesive layer, and improve the bonding quality.  

6. Maximum strength  

Although super glue can form good adhesion in a short time, it takes 3-5 days to reach maximum strength. Therefore, joints that bear heavy loads should be left to stand for a sufficient amount of time before use.

7. Storage  

All-purpose adhesive should be stored in a cool, dry place, away from children. Avoid direct sunlight, high temperatures, poor sealing, or prolonged exposure, as these can cause the solvent to evaporate, resulting in excessive viscosity and making it unusable. It can be diluted with toluene, ethyl acetate, methyl ethyl ketone, or acetone; if it can be stirred thoroughly, it can still be used.  

8. Other  

For furniture surfaces with wood grain or cat's eye patterns, it is recommended to use water-based latex. Otherwise, the strong solvents in all-purpose adhesive will dissolve the wood grain pattern. All-purpose adhesive cannot bond plastics that can be dissolved by toluene, ethyl acetate, methyl ethyl ketone, acetone, etc., such as rigid polystyrene foam (commonly known as polystyrene board). In these cases, it is recommended to use neoprene latex instead.