Types of Wood Glue How to Use Wood Glue

Woodworking adhesive, in a narrow sense, refers to the adhesive used in woodworking industry. Broadly speaking, woodworking glue can be used in a wide range of industries, not just woodworking industry. Adhesives are essential in woodworking industry. It is no exaggeration to say that if properly used, we can turn decay into magic, turn waste into treasure, turn small into big, turn bad into excellent, and turn excellent into talent. The following small series introduces the types of woodworking glue and the use of woodworking glue.

Types of woodworking adhesives

1, outdoor woodworking glue

Outdoor woodworking glue is industrial-grade white latex. You can wash it with water when it is not dry. When it is dry, it is translucent, grindable, non-toxic, colorable and waterproof. Glued MDF. The heat resistance is as high as 1 10℃, which is specially used for bonding various wood products in woodworking or manufacturing plants. It is suitable for bonding all kinds of soft and hard wood, MDF medium density fiberboard, fireproof board, sawdust and other materials, and bonding all kinds of indoor furniture with wood.

2, polyurethane woodworking glue

Polyurethane woodworking adhesive is a high-grade woodworking adhesive. Brown, light yellow after drying, will expand, so it is also suitable for bonding/filling small cracks. Non-toxic, pressure resistant, acid and alkali resistant (wood glue will reduce its adhesion when it meets acid and alkali). After drying, it can be polished, dyed and painted, and its heat resistance is as high as 140℃. Suitable for bonding indoor and outdoor wood, glass, density board, metal, cement, porcelain and most plastic products. Wood can bond almost all materials.

3. Woodworking glue

Woodworking glue is specially used to bond all kinds of indoor wood products and furniture. It is milky white, which can be washed with clean water when it is not dry, and transparent after it is dry. Non-toxic and pollution-free wood. Can bond all kinds of rough wood, cloth, paper, leather and other materials (MDF can not be bonded). Wooden handmade products are bonded or repaired with furniture, wooden photo frames, various wooden stools, wooden wine racks, wooden cabinets, broken wood, etc.

Use of woodworking glue

1, temperature

In different seasons, it is necessary to measure the working environment temperature and wood surface temperature in time. To some extent, the temperature determines the speed of glue crosslinking. The surface temperature of wood is closely related to the holding time of jigsaw puzzles. At different temperatures, the service life of glue is different: in summer, the mixed glue can be used for 30 minutes (that is, the earlier it is used, the better); In winter, the prepared glue can be used for 60 minutes.

2. Rubber mixing

The main agent and curing agent should be mixed in strict accordance with the weight ratio of 100: 15, and fully stirred evenly. The mixed splicing glue should be used up in a controlled time. It is forbidden to mix impurities such as sawdust and dust or add water when mixing glue. It is forbidden to mix the main agent and curing agent before use. Pay attention to sealing and retention after taking glue.

3. Moisture content of wood

After natural moisture regain, the moisture content of dry wood should be controlled within 7- 12%. When the moisture content of wood is lower than 7%, it may cause the phenomenon of excessive water permeability and exudation of wood, resulting in the lack of glue on the bonding surface and cracking. The high moisture content of wood will directly lead to poor infiltration and exudation, and it is difficult to form glue nails, and the cross-linking reaction is not complete, which is easy to lead to glue opening. The critical moisture content difference of wood should be controlled within 3%.

4, wood processing accuracy.

The accuracy of wood processing should be within 0.65438 0.05 mm. The bonding surface of wood should be free from processing defects such as "gnawing head and finishing". This wood has a good right angle. There should be no "planing, sawing and carbonization" on the bonding surface of wood. It is forbidden to use wood whose bonding surface has been polluted by grease, dust, etc.

Reasons for the opening of woodworking glue

1, moisture content of the bonding substrate

White latex is a water-soluble adhesive, and its bonding principle is that colloid is absorbed by wood fiber and becomes a whole. If the moisture content of the bonding material is greater than 12%, the bonding effect will be reduced on the bonding surface.

2, the flatness of the adhesive substrate

The flatness of bonding substrate is the premise of bonding, and the flatness error of wood is required to be controlled within 0. 1 mm, and the protrusion of local edge will also cause other bonding surfaces to be unable to bond closely.

3. Is the coating quantity scientific?

Too much glue and too much residual colloid can't be cured, which leads to weak adhesion and even deformation and mildew of the plate. When the amount of glue applied is too small, the phenomenon of glue opening occurs because the effective colloid absorbed by the bonding surface is not enough. The scientific standard of glue distribution is generally 250-300 g /m2, and even granular rubber particles should be extruded between the two pressing surfaces by naked eyes.

4. Is it standard pressure?

Uneven or insufficient press pressure is also the main reason for glue opening. The simplest but very standard method to check whether the pressure of the press is balanced is to put four A4 papers on the four corners of the press, and press all the presses to the bottom to see if these four A4 papers can be taken out. The most standard printing machine can't take A4 paper out at any angle.

5. The colloid coated on the bonding surface has dried before pressing.

Workers use the same press to press plates in batches during construction. Glue the first board until the last board is glued and the press is put down. This time period may last for more than half an hour, which is enough for the colloid on the lower gluing board (the first gluing board) to solidify, that is, when the press is put down, the colloid on the lower pressed board has solidified, that is, no pressure is applied. This phenomenon of dry surface before pressing is most common in summer. When the two bonding surfaces are pried open due to the dry surface before pressurization, there is usually a phenomenon that there is glue on one side and no glue on the other. When the surface is not serious, the rubber surface on the pried surface will be in a "net" state.

6. The content of glue used is low.

The hardness of glued wood directly determines the quality of glue used. The harder the wood, the higher the quality of the glue. If the wood is hard, but the content of effective substances in the glue used can not reach, the bonding effect can not be guaranteed.