Recently, a customer consulted us. They used a machine to bond the substrate and wood veneer. After the workers applied the wood veneer adhesive, the products cracked and blistered. They asked us why this happened and for solutions. Below, Anhui Lichao Company shares the causes of cracking and blistering after painting on machine-applied veneer adhesive.

Cause 1: The adhesive contains oily substances
When workers accidentally introduce oily liquids or substances into the adhesive during operation or storage, the bonding will affect its effect. Therefore, in this case, the only solution is to replace the wood veneer adhesive with a new one and ensure proper storage in the future.

Cause 2: Low pressing pressure, thick glue line after bonding
When workers use the machine for veneering, if the equipment pressure is insufficient and the glue contact is poor, the glue line is generally thicker, which can also lead to cracks and bubbles. Therefore, the above situation can be handled by appropriately increasing the machine pressure.

Cause 3: The amount of wood veneer adhesive applied is too low
To save costs, many factories, when applying glue, do not meet the manufacturer's recommended application amount; for example, the application amount is too low. In this case, simply increasing the amount of wood veneer adhesive applied so that a reasonable glue line is visible can solve the problem.

Cause 4: Insufficient curing agent in the two-component adhesive or the curing agent has passed its active period
When bonding thicker wood veneers or when stronger weather resistance is required, it is necessary to appropriately add curing agent. However, if the proportion of curing agent added is insufficient or it is not used in time after mixing, this can also lead to cracking after the active period. If this is the cause, the curing agent must be properly formulated and used within its effective period.

Cause 5: Oily substances on the surface of the bonded substrate
Sometimes, when panels are stored in a warehouse, they can easily become contaminated with oily substances. When bonding, the adhesive cannot properly penetrate, leading to cracking. In this case, the substrate must be cleaned or polished before bonding.