If you are an avid do-it-yourselfer or work professionally with different materials, you will not be able to avoid the question of the right glues. We are not talking here about glue sticks or the well-known super glue. Instead, let’s see what the properties and advantages of epoxy glue are.
What is epoxy glue?
Epoxy glue is used to join very strong and generally durable materials. Epoxy glue is mainly used with pretreated and painted metals or with composite materials. Epoxy glue consists of equal parts resin and hardener. Mixing between the two should be done shortly before the adhesive is used, as the pot life – the time the epoxy adhesive can be cured – is relatively short. Processing time is usually around 10 minutes.
The two-component glue, or the two-component epoxy adhesive, then hardens into an extremely stable thermosetting plastic, so that it can no longer be changed by mechanical or thermal effects and is very resistant. Depending on the product, the hardening is complete after approximately 24 to 48 hours. The higher the ambient temperature, the more efficiently the material hardens. This means that the resistance increases at higher temperatures. There are also epoxy adhesives on the market, the components of which are already mixed. This solution is obviously easier because mixing resin and hardener can often be a bit difficult and tedious. However, these pre-mixed adhesives have the disadvantage of requiring a higher curing temperature.
Advantages and disadvantages of epoxy glue
Epoxy glue has some disadvantages, but the advantages outweigh the disadvantages. Its compatibility with a wide variety of materials is particularly important.
The benefits of epoxy glue
- Extremely high resistance to thermal and mechanical influences
- Resistance to most substances
- Works without solvent
- Suitable for a variety of materials
- Compatible with a wide range of additives such as colorants
- Predetermined pot life
- Option to add an inhibitor to extend pot life
- Ideal for glass and metal, wood and metal or aluminum and steel connections. No fretting corrosion.
- Better vibration damping Adhesive connections are made over a large area. This allows them to better dampen vibrations than welded, screwed or riveted connections.
- No thermal deformation? At high temperatures, the connected parts retain their intended shape. In addition, heat sensitive materials can be processed.
The disadvantages of epoxy glue
- An exact mixture of equal parts between resin and hardener is necessary because otherwise the hardening does not take place
- Pot life is limited
- Relatively expensive
- Potentially harmful to health and the environment according to European Union directives. On this subject, as soon as you handle epoxy glue as with all products of its kind, you must follow certain instructions to protect your health. Always wear gloves and work in well ventilated areas. Of course, epoxy glue is a difficult product to recycle.
- Cannot be disassembled. What has been glued is difficult to disassemble. Replacing the parts that are glued with epoxy glue is therefore more complex and expensive.
- Aging process. It can happen that epoxy glue ages badly due to mechanical, chemical or meteorological influences – for example humidity. These can alter the bond strength.
- Use at limited temperature. Bonds can become brittle at too low temperatures, soften and melt at too high temperatures, or change shape.
- Curing time. Epoxy glue takes a while to harden. This process can easily take dozens of hours.
- Surface pre-treatment. In order to achieve optimum bonding results, the surfaces to be bonded must first be cleaned of all traces of oil, grease, dust and other dirt. This requires an additional work step.
How to glue with epoxy glue?
Two-component epoxy glue, resin and hardener, is usually available in dual-chamber cartridges. This means that the two components are only mixed with each other directly just before use. Today’s technology allows you to use this kind of gun cleanly and easily. The best way to do it:
- You must first carefully clean the surface to be treated: remove grease and other dirt. For this, you can use a lint-free cloth and an appropriate cleaning product such as acetone.
- After cleaning, you should no longer touch the surface to be bonded with your bare hands, as the greasy film on the skin can also lead to insufficient adhesion.
- The surface should be slightly rough, because only then does the epoxy glue adhere well to the material. To do this, you can sand or sand the surface.
- Then sweep the surface to remove dust, or vacuum – with a suitable vacuum cleaner.
Remember to pre-treat single-core plastics with a primer afterwards to optimize material adhesion.
The two-component adhesive is usually supplied in a double syringe. Remove the tip from this. Now screw on a mixer attachment which should be included in the delivery. Hold the syringe with the mixer tip up and gently push the plunger to remove any air bubbles.