How To Glue Acrylic: A Comprehensive Guide

Acrylic, also known as Plexiglass or Perspex, is an incredibly versatile and durable material with applications spanning from aquarium construction to signage and displays. When working with acrylic pieces, especially in the context of gluing and joining them together, it is crucial to prepare the surfaces properly and use the right adhesive. However, gluing acrylic can prove challenging due to its unique properties. This guide delves into the best techniques and products for successfully bonding acrylic to other plastics and acrylic within the UK market.

Not all adhesives are created equal when it comes to bonding acrylic successfully. Here are some of the most prevalent options available in the UK market:

• Solvent-based Adhesives: Adhesives such as Tensol, Bostik, and EvoStik work by partially dissolving the acrylic surface, creating a strong bond. These are suitable for bonding acrylic to itself as well as other plastics.
• Cyanoacrylate (Super Glue) Adhesives: Brands like Loctite and Gorilla Glue offer specialised super glue formulations designed specifically for plastics, including acrylic. These adhesives cure rapidly, making them ideal for small projects or repairs.
• UV-Curing Adhesives: Products such as Bondic and Welder utilise ultraviolet light to cure the adhesive, resulting in a strong, clear bond. These are particularly useful for bonding acrylic to itself or other transparent plastics.

While acrylic adhesives are generally safe, it’s essential to take appropriate safety measures. When using solvent-based glue, always work in a well-ventilated area due to the strong fumes. Wear gloves and safety glasses to protect your hands and eyes, especially when working with solvent-based adhesives.

Proper surface preparation is crucial for achieving a durable, long-lasting bond when gluing acrylic. Ensuring that edges are smooth and, if possible square, is essential for optimal bonding. Begin by thoroughly cleaning the surfaces with a household cleaner or isopropyl alcohol to remove any dirt, grease, or contaminants. For enhanced adhesion, lightly sand or abrade the acrylic surfaces before applying the adhesive.

Once you’ve selected your adhesive and prepared the surfaces, it’s time to apply the glue. Follow the manufacturer’s instructions carefully, as application techniques may vary depending on the adhesive type.

• For solvent-based adhesives, apply a thin, even layer to both surfaces and allow the solvent to partially evaporate before joining the pieces together. Use an applicator bottle to apply solvent-based acrylic glue, lightly squeezing the bottle to release the glue and ensure it flows into the joints and seams using capillarity.
• With cyanoacrylate (super glue) adhesives, apply a thin bead along one surface and quickly join the pieces, applying even pressure. Some superglues come with accelerants that can speed up the curing process.
• UV-curing adhesives require exposure to ultraviolet light to cure, so follow the manufacturer’s instructions for application and curing times precisely.

Regardless of the adhesive used, it’s crucial to clamp or apply even pressure to the joined pieces until the adhesive has fully cured. This ensures a strong, uniform bond.

Working with acrylic can be tricky, so here are some tips and tricks to help you achieve better results:

• Thickness Considerations: When working with thin acrylic sheets (3mm or less), take extra care to avoid over-clamping, which can cause the material to crack or distort.
• Curved or Irregular Shapes: For curved or irregular shapes, consider using a flexible adhesive like silicone or a gap-filling formula to ensure proper coverage and bonding.
• Preventing Air Bubbles: To avoid air bubbles from becoming trapped in the bond, apply the adhesive in a smooth, even layer and gently press the pieces together.
• Bonding Acrylic to Other Plastics: When bonding acrylic to other types of plastics, it’s essential to choose an adhesive compatible with both materials. Solvent-based adhesives and certain cyanoacrylates may be suitable but always refer to the manufacturer’s recommendations.
• Flame Polishing Edges: For clear acrylic, flame polishing the edges using a propane or MAP gas torch can melt the edges slightly, resulting in a transparent, polished appearance. This technique improves the clarity of cut pieces and enhances the visibility of glue when used with transparent materials.

One of the most common applications of acrylic gluing is bonding acrylic sheets to themselves. This technique is often used in the construction of aquariums, terrariums, signage, and displays. Here are some tips for successful acrylic-to-acrylic bonding:

1. Surface Preparation: Thoroughly clean and lightly abrade both acrylic sheet surfaces to ensure optimal adhesion.
2. Adhesive Selection: Solvent-based adhesives, cyanoacrylates, and UV-curing adhesives are all suitable options for gluing acrylic sheets together. Consider factors such as cure time, strength, and clarity when choosing the appropriate adhesive.
3. Clamping and Curing: Apply even pressure to the joined pieces using clamps or weights, and allow the adhesive to cure completely according to the manufacturer’s instructions.
4. Reinforcement: For added strength, consider reinforcing the bond with acrylic cement or solvent welding techniques, especially in areas subject to high stress or pressure.

In some cases, you may need to bond acrylic to other types of plastics, such as polycarbonate or PVC. Super glue is particularly suitable for bonding opaque acrylic where the dried glue is not visible or noticeable. This can be more challenging, as different plastics have varying chemical compositions and compatibility with adhesives. Here are some tips for successful bonding:

1. Plastic Identification: Accurately identify the type of plastic you’re working with, as this will determine the appropriate adhesive choice.
2. Adhesive Selection: Solvent-based adhesives and certain cyanoacrylates may be suitable for bonding acrylic to other plastics but always refer to the manufacturer’s recommendations for compatibility.
3. Surface Preparation: Proper cleaning and abrading of both surfaces is essential for optimal adhesion.
4. Test for Compatibility: Whenever possible, perform a small test bond to ensure compatibility between the acrylic, the other plastic, and the chosen adhesive before proceeding with the full project.

Gluing acrylic may seem daunting initially, but with the right adhesive, proper surface preparation, and careful application techniques, you can achieve professional-quality results for bonding acrylic to itself or other plastics. When working with plastic sheeting, using acrylic cement is crucial for bonding the sheets together, ensuring smooth edges and precise application. Remember to prioritise safety, follow manufacturer instructions meticulously, and don’t be afraid to experiment with different adhesives and techniques to find the optimal solution for your projects. With patience and practice, you’ll soon be confidently bonding acrylic like a seasoned professional.