The wide range of existing adhesives makes it possible to grip all elements together. When gluing, you should keep in mind the following:
- The stability of the material to the solvent
- The shape and size of the surface
- The preparation of the surface
Bonding means joining elements through a layer of adhesive. This layer is formed when the adhesive is hardened: on drying (e.g., white glue) or by chemical reactions (e.g., two-component adhesives). Duration of union depends, apart from the form of the surface and its preparation, on two factors: adhesion and cohesion. When a damp paper remains practically attached to a glass or between two glasses by interposing a fine film of water between them, it is due to the adhesion force, increasing the contact between the adhesive film and the material. This contact is achieved if there are no different films or air bubbles between the two objects. For us, this indicates that the surfaces to be united must have no trace of fat or dust. Lightly scratching the surfaces may increase the adhesion strength (unusual particle cleaning and surface loading). By cohesion it is meant to join the components together. This depends on the quality of the adhesive. The strength of cohesion increases when the adhesive film is homogeneous and not too thick.
It should also be borne in mind that there are adhesives that can fill small voids or cracks such as two-component adhesives, strong UHU and white adhesives. However, impact adhesives require the surface to be glued to fit perfectly.
We should keep the boxes of adhesives, as the instructions for use are more complete than those on the tube.
Types of Adhesives
White Adhesives – Made of synthetic resins dissolved in water. On evaporation of water, the resins form an almost transparent layer. When using these adhesives it is necessary that at least one of the surfaces to be glued should be porous to allow the water to evaporate. These adhesives are especially used for bonding wood, boards and cork. They are rarely used for the gluing of textile materials, cardboard and cardboard papers. For this purpose there are special adhesives. White adhesives, due to their water content, deform the paper.
Dissolvent Adhesives – These consist of synthetic resins – for example, synthetic rubber – diluted in solvents. The adhesive film gets hard when the solvent evaporates. This means that the dissolvent must go out through the united material through the common union. So you can always stick to the material if it is permeable (paper, cardboard, fabric, leather, wood) or when it comes to joining impermeable materials (metal or plastic) to a long and narrow union. We must keep in mind that some solvents can attack the plastic. That is why we should test them in advance. There are special adhesives for expanded and extruded polyester, for methacrylate and for PVC. When using these adhesives, do not forget to wear the appropriate protective mask and suitable gloves!
Impact Adhesives – These are used in the construction of the models, especially for the joining of the land layers of the topographic model. They can also be used to join two elements of waterproof material. The two surfaces must be covered with a very fine coat of adhesive. Afterwards the solvent is allowed to evaporate and the two surfaces are continuously bonded. To do this, use a carpenter hammer or a rubber roll.
Two-component adhesives- Formed by a hardener and bond, mixed together before use. Always observe the manufacturing instructions regarding the proportions of the mixture! No large quantities should be mixed once, since some adhesives have a short hardener time (5 minutes). The fastenings resist heavy loads (e.g. UHU plus 300 can resists up to 300 kg/cm2). These adhesives are used for bonding metals, ceramics, glass and plastic together when the strength of bonding is required.
Super Glues – A very interesting type to build models is the instant adhesive, especially when pursuing fast and lasting joining, or when you can not push the parts together for a long time. There are instant adhesives for both porous and other materials. They can be used for metal, plastic, showcases, porcelain and fabrics. When using instant adhesives, care must be taken to avoid contact with eyes or skin. When using these adhesives, do not forget to wear the appropriate protective mask and suitable gloves!
Types of unions
The length of the union depends not only on the adhesive but also on the form of the assembly; the most important of these are:
- At the ends
- At tilted ends
- Within a square, covering the end
- At the ends with connectors on one side
- At the ends with connecting elements on both sides
- With miter box
- Simple position
Preparation of soldering surfaces:
- Clean up unusual particle surfaces (particulate debris and dust)
- Surface sanding by grinding
- Degrease the surfaces with acetone or alcohol
- Allow the surfaces to dry after they have been cleaned
- Do not touch the surfaces to be glued once they have been prepared
- Apply an adhesive forming a thin and homogeneous layer
- Let it dry as long as it takes
- Avoid adhering to the dust or dirt of the recently added adhesive. Pause piling until the items are united.
Adhesive rolls and self-adhesive paper
Apart from glues and adhesives, we also use adhesive rolls or self-adhesive paper on both sides. Adhesive rolls are used to temporarily fix items. When removing the roller coil, be careful not to sprinkle the element. For this, rollers with poor adhesion are used for this. For bonding coloured paper to a transferable material such as polystyrene or methacrylate, and to bond together thin sheets of metal, polystyrene and methacrylate, adhesive foils are added on both sides. No element should be porous, but have a clean surface without grease. The advantage of self-adhesive paper is the possibility of joining large surfaces in a short time. Coloured adhesive rolls of 0.5 mm wide have an important help to reproduce the cut of the glass stack carpeting to a scale of 1: 200, 1: 100 and 1:50.
The base for cutting made of homogeneous rubber helps us a lot in our work. While cutting the cardboard or wood by supporting a cutter by a ruler, there is always the danger of the base going beyond the cut line and breaking it, the homogeneous rubber of the special bases restores and does not degrade or degrade the cutter blade. These bases allow precise cuts and keeping the corners clean.