Splicing adhesive refers to the adhesive for wooden products. The adhesive bond has very high bonding strength. High-quality splicing adhesive generally has good water resistance, heat resistance, and solvent resistance. The main component of high-quality splicing adhesive is a polymer with excellent waterproof effect, and the curing agent is generally isocyanate. The main color is milky white viscous liquid, and the curing agent is brown. Below, I will introduce the usage methods and precautions of splicing adhesive, hoping to be helpful to everyone.

Wood control and ambient temperature.

1. Control wood moisture content to 8-12% (hardwood), 8-14% (softwood), with the moisture difference between adjacent splicing surfaces less than 3%.
2. Keep the splicing surface flat, without wavy surfaces or bending, and avoid twisted surfaces. For easily deformable wood, especially hardwood, it should be spliced on the same day. If left overnight or for a longer time, the splicing surface is prone to deformation due to moisture absorption, and must be re-flattened. The splicing surface should be perpendicular to the bottom surface.
3. Before splicing, remove wood ash and dust from the wood surface, and ensure it is free of oil.
4. Each adhesive has a minimum limit, especially in winter and autumn. Temperatures below this limit will seriously affect the bonding strength of the adhesive.

2. Glue mixing
1. Ratio: Splicing adhesive : curing agent = 10:1.0~1.5 (weight ratio), adjust the ratio according to wood density, temperature, and humidity. Once the curing agent ratio is confirmed, it must not be changed arbitrarily, otherwise it will seriously affect key properties such as bonding strength and water resistance.
2. When preparing the curing agent, choose the size of the glue container based on the splicing workload and determine the amount of glue to mix. Only use half of the container's volume for the glue mixture, otherwise it may overflow due to foaming from the chemical reaction.
3. It is recommended to choose a flat-bottomed round container for glue mixing, as it is easier to stir the curing agent evenly.
4. Do not add water to the splicing adhesive.
5. Splicing adhesive mixed with curing agent should be used within the working time. Bubbles during use are normal.
7. Unused curing agent must be stored in a sealed container and must not be mixed with water vapor to avoid chemical reaction.

3. Glue application
1. You can use an automatic gluing machine, manual gluing machine, paint roller, pig bristle brush, or rubber scraper to apply glue evenly. The glue application amount is generally controlled between 200g-250g/m².
2. Users should determine the glue application amount based on the day's temperature and humidity. When the temperature is low, humidity is high (above 80%), and the wood is soft, apply less glue. When the temperature is high, humidity is low (below 40%), and the wood is hard, apply more glue.
3. After the workpiece is coated with adhesive, splice it as soon as possible to prevent film formation on the adhesive surface, avoiding false splicing and easy glue line opening.

4. Pressing
1. Regardless of the pressing method used, multiple points within a press point should be evenly pressed at about 30cm intervals. The pressing time control depends on the on-site temperature, air humidity, wood hardness, and workpiece size.
2. Pressure: Softwood (≤0.4) 0.8~1.0 Mpa, medium hardwood (0.4~0.7) 1.0~1.2 Mpa, hardwood (≥0.7) 1.2~1.5 Mpa.
3. When pressing, pay attention to防止 the wood strips from pulling out (non-vertical, large and small ends are most prone to this). If pulling out occurs, release pressure and reset, do not reset under pressure. Check whether there is continuous and uniform adhesive overflow at the joint. If there is no adhesive overflow, it indicates insufficient glue application or too long wait time after gluing before pressing. This phenomenon should be corrected immediately. The pressing inspection process cannot be ignored.
4. Room temperature curing requires long pressing time. High-frequency curing is determined by the machine parameters, with pressing time of only a few minutes.

5. Conditioning
After the workpiece is released from pressure, the adhesive is only initially cured. The extruded adhesive is slightly hardened, and a stacking conditioning process is necessary. Based on different woods and under different climatic conditions, set the conditioning period to ensure normal use in the next process. When stacking and conditioning under conditions of low temperature, high humidity, and hardwood, the conditioning time requires overnight or a full day. When stacking and conditioning under conditions of high temperature, low humidity, and softwood, the conditioning time is 6-8 hours.

6. Residual glue treatment.
Splicing adhesive mixed with curing agent that cannot be used within the specified time cannot be continued to be used, as it will affect the splicing quality. Therefore, adjust the glue amount according to needs to avoid wasting residual glue.

Since the characteristics of each splicing adhesive are different, specific process parameters should follow the product manual provided by the manufacturer.