Best Glue for PLA 3D Prints

When bonding PLA 3D prints, choosing the right glue can ensure a strong and long-lasting bond. Different types of glue have their own characteristics in terms of usage, curing time, and applicable scenarios. This article will introduce three experimentally verified glues and summarize their characteristics and application methods.

Source: https://ecoreprap.com/3d-printing/how-to-glue-pla/

This article refers to Andrew W's evaluation of various glues for bonding PLA in the video. To ensure the reliability of the test, he uniformly used PLA samples with a layer height of 0.2mm and a filling rate of 20% to ensure consistent experimental conditions.

Surface treatment: Polished and unpolished PLA surfaces were tested to observe the effect of surface treatment on bonding.

Glue application: According to the instructions for use of each glue, apply it evenly on the joint surface and clamp it as needed.

Curing time: Place it according to the recommended curing time of the glue to ensure that it is fully cured before testing.

Strength test: Bond strength is evaluated by tension, torsion and shear.

The results show that Welo-On 16, CA (Superglue), and Contace Cement are the three best glues.

Weld-On 16

Weld-On 16 is a solvent-based adhesive that dissolves the surface of PLA, melts it and fuses it together to form a weld-like structure. This method makes the bonding part a whole, rather than just a simple surface attachment, so it has high strength and is suitable for structural parts that bear large loads or are used for a long time.

Consumers commented that Weld-On 16 performs well in bonding PLA and provides excellent bonding strength, especially for structural parts that require a stable connection. However, due to its strong fluidity, it is easy to overflow and stain the surrounding area when used, so it is recommended to use a dropper or a narrow-mouthed bottle for precise glue application. In addition, the glue takes a long time to cure, usually waiting for 24 hours to reach the best strength, so you need to be patient during use.

It is worth noting that Weld-On 16 has a certain solvent smell. When using it, it should be carried out in a well-ventilated environment to reduce the discomfort caused by the pungent smell. At the same time, because it can slightly dissolve the surface of PLA, excessive application may affect the appearance of delicate parts. Therefore, it is recommended to test it in a small area before use to ensure the ideal bonding effect.

Source: https://www.tapplastics.com/product/repair_products/plastic_adhesives/weld_on_16_cement/132

CA glue (cyanoacrylate glue)/Super glue

CA glue is different from traditional water-based glue. It is an acrylic resin glue whose main component is cyanoacrylate. When CA glue comes into contact with moisture in the air or trace moisture on the surface of the bonding material, it will quickly polymerize to form a strong plastic-like solid and complete the bonding. This process releases a small amount of heat, allowing it to complete the initial curing in a few seconds, while full curing usually takes 24 hours.

When using, apply a small amount of glue to the bonding area and quickly align the parts. If the surface is not flat enough, it can be used with caulking powder to enhance the bonding effect. CA glue itself is relatively hard and brittle after bonding, so cracks may occur when subjected to large shear forces or impacts.

Consumers say CA glue performs well when bonding PLA, especially for small areas and high-efficiency bonding needs. It cures quickly, but the bond is brittle and may crack when subjected to force or impact. In addition, the glue is easy to stick to your hands, so it is recommended to use gloves or tweezers to operate. If it is accidentally stained, it can be removed with acetone.

Contact Cement

Contact cement is a type of glue that needs to wait for a moment before bonding after being applied on both sides. It can form a strong bonding layer at the bonding point and retain the flexibility of the material to a certain extent, making it more resistant to pressure and slight impact.

For best results when bonding PLA, make sure the surface is clean and sand it lightly with sandpaper to improve adhesion. Apply a layer of contact glue evenly on both parts and let it dry for a few minutes until it feels sticky. Once connected, the bond is immediate, but full strength takes several hours to form. Clamping is usually not required, but applying even pressure helps to achieve a seamless connection.

Contact cement is particularly suitable for assembling large or thin-walled PLA prints, connecting surface laminates, or bonding flexible parts that need a little flexibility. However, it may not be suitable for high-strength structural connections because it does not fuse the plastic like solvent-based adhesives.

Related article: How to Glue 3D Prints: A Complete Guide for Seamless Connections

Alternative PLA bonding methods

Glue bonding is the best solution for most scenarios - no tools required, easy to operate and controllable strength, and there are some methods suitable for special needs such as extreme forces, appearance requirements or repeated disassembly and assembly:

PLA welding

Use a soldering iron or 3D pen to melt the surface for super strong fusion, which is best for heavy-duty parts.

Heat fusion

Use a hot air gun to soften the edges for seamless and beautiful connections.

Mechanical fasteners

Use screws or snap-on designs to achieve adjustable/reusable connections, which are ideal for modular components.

Choosing the right glue is essential to ensure the bonding effect of PLA 3D printed parts. Whether it is providing a solid connection for load-bearing structural parts or performing daily repairs, you can get the ideal bonding effect with the right surface preparation and appropriate glue application method. If you are looking for high-quality 3D printing materials and services, JLC3DP provides you with professional solutions to help you complete various PLA bonding needs.