Epoxy resin adhesive coating is the process of applying epoxy resin adhesive onto the surface of the object to be bonded using appropriate methods and tools. The correctness of adhesive application has a significant impact on the quality of bonding. The difficulty of coating epoxy resin adhesive is closely related to its viscosity. For solvent-free epoxy resin adhesive, if its viscosity is too high or becomes viscous due to low temperature, causing difficulty in coating, the surface of the adhered material can be preheated with a hair dryer or other methods to 40-50 ℃, reducing the viscosity of the coated epoxy resin adhesive and making it easier to wet the adhered surface. If it is a solvent based epoxy resin adhesive with high viscosity, it can be diluted with the corresponding solvent before coating, which is beneficial for wetting.
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Glue application times

The number of times the adhesive is applied varies depending on the properties of the epoxy resin adhesive and the adhered material. For solvent-free epoxy adhesives and dense adhesives, a single coat of adhesive is generally sufficient, while most solvent based epoxy resin adhesives and porous adhesives or adhesive layers that require a certain thickness for construction require 2-3 coats of adhesive. For multiple coats of glue, be sure to apply the next coat after the first coat has dried, and do not rush

Glue application amount
The amount of adhesive applied is also related to the type of epoxy resin adhesive and the type of adhesive. For porous adhesives, the amount of adhesive applied should be larger. The amount of glue applied directly determines the thickness of the adhesive layer. Generally, the thinner the adhesive layer, the fewer defects, deformation, shrinkage, and internal stress, and the higher the bonding strength. The adhesive layer should be thin rather than thick. If the adhesive layer is too thick, it is not only useless but also harmful. Therefore, while ensuring that there is no shortage of adhesive, it is better to make the adhesive layer as thin as possible. It is generally believed that the thickness of the adhesive layer should be controlled between 0.08-0.15mm.

Glue application method:
The method of coating varies depending on the shape of the epoxy resin adhesive. For liquid, paste or paste like epoxy resin adhesives, brushing, spraying, dipping, scraping, rolling, injection, etc. can be used

Brushing method
This method involves using a brush to apply adhesive solution onto the surface of the object being adhered. The brushing method is suitable for brushing any shape of surface. For transformer core insulation black paint LD-2055, when brushing the glue, it should be done in one direction, not back and forth, and the speed should be slower to avoid introducing bubbles.
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Spray method

This method uses a specially designed glue gun and dry compressed air to spray the glue onto the bonding surface. The spraying feature is that the glue layer thickness is uniform, the production efficiency is high, and it is suitable for large-area bonding. For large-area pool waterproofing products - Liding waterproof paint construction process, it can be applied through spraying.

Dip coating method
 This method is a process of immersing the adhesive into an epoxy resin solution for adhesive bonding. For the immersion coating of epoxy resin adhesive, it is mostly used for the application of insulation paints such as LD-401/LD-401-C. By rolling or dripping the coil in the adhesive solution, the insulation paint can be fully filled between the gaps of the coil, playing a role in insulation and sealing. The dip coating method is suitable for small, thin, and complex adhesives, with the advantages of simple equipment, low adhesive consumption, and high production efficiency. The commonly used immersion coating methods include manual method, rotary immersion coating method, centrifugal immersion coating method, vacuum immersion coating method, transmission immersion coating method, etc.

Scratch coating method
This method is a scraper, which applies a paste or paste like epoxy resin adhesive to the bonded and sealed areas. For Liding adhesive steel, the paste like structural adhesive can be evenly applied to the surface to be bonded through the scraping process, and the purpose of structural reinforcement can be achieved after later bonding curing

Rolling coating method
This method involves immersing a roller in the adhesive solution first, and then transferring it to the surface that needs to be bonded or coated. When applying adhesive to a wide and flat object surface, it is more convenient to use a rubber roller for operation. The adhesive film applied by rolling is relatively uniform without sagging, but the corners are not easy to roll and need to be brushed back with a brush. The scope of construction products includes waterproof paint, colored pavement adhesive, ground insulation paint, etc.
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Injection method

This method involves injecting epoxy resin adhesive into joints, areas to be bonded, or components that require sealing through specialized containers using manual, mechanical, pneumatic, and other pressure methods. For example, 50ml of LD-EP706 or 400ml of Liding planting adhesive can be packaged in a glue cylinder, and can be directly applied with a glue machine or glue gun in the later stage. This not only reduces the later mixing process, but also improves the curing surface effect and accelerates production speed.

No matter what kind of adhesive method is used, it should be carefully and meticulously applied, requiring uniform and consistent application of adhesive, and avoiding the mixing of air. Ultimately, a glue layer with no omissions, no missing adhesive, no bubbles, no accumulation, and an appropriate thickness after bonding should be obtained. If the viscosity of the epoxy resin adhesive is too high, it can be appropriately reduced by heating or formula improvement to improve the wetting and penetration properties of the epoxy adhesive, thereby ensuring the bonding strength. As for the adhesive surface, in principle, each surface of the adhesive should be evenly coated to ensure sufficient wetting. However, for large-area and low strength bonding, point coating, line coating, or a combination of point and line coating methods can also be used to apply adhesive, which saves both adhesive and labor.