Which Glue Can You Use for PETG 3D Prints? Explained

Gluing 3D printed PETG parts together is usually a slightly more challenging process compared to other popular filaments such as PLA and ABS, as the chemically resistant nature of PETG plastic prevents most glues from forming bonds that are strong enough with it, which ends up with the glued parts separating pretty quickly.

In this guide, we will take you through the types of glue you can use on your PETG 3D prints without experiencing the issues that the resistant properties of PETG bring to the table, whether for combining the two pieces you have printed separately or to fix damaged parts you would prefer to repair rather than print them again.

Which Glue Can You Use for PETG 3D Prints?

When it comes to gluing the parts you have 3D printed with PETG filament, there are a fair few options available, with each option coming with its own strengths and weaknesses that make them more suitable for some and less for other use cases.

Superglue (Cyanoacrylate)

Cyanoacrylate, more commonly known as superglue or instant glue, is the first product that comes to mind whenever it becomes necessary to glue multiple pieces of 3D-printed PETG together on short notice, as it’s one that’s readily available in almost any household due to its wide range of usage areas, whether it’s making minor repairs on decorative items around the house, or putting together miniature figurines.

superglue


The advantages of superglue, as you may predict from previous uses in different areas, are that it bonds quickly, which makes it possible to join your PETG 3D printed parts together almost instantly, that it’s the most straightforward to apply out of all the options available, which makes it practically impossible to have any issues regarding application even without experience, and that it dries clear, which ensures that the glue won’t be visible from the outside even when you’re working with parts that are transparent or light-colored.

On the other hand, the disadvantages of using superglue to join your PETG prints are the glue becoming quite brittle, which takes flexibility out of the question for the part, low heat resistance, which rules out the usage of the part for high-temperature applications despite PETG itself being considerably resistant to heat, and limited gap-filling ability, which effectively makes it necessary for the surfaces you’re bonding together to match each other with as little irregularities and gaps as possible for the glue to hold.

With these advantages and disadvantages in mind, we can say that superglue is a perfectly suitable choice for cases where you need to connect your PETG 3D printed parts quickly and easily without too much emphasis on the durability and the strength of the bond, with examples such as architectural models, prototypes, and figurines coming to mind.

On the flip side, in scenarios such as putting together structural components that will need to flex to fulfill their purpose or parts that will see outdoor usage under direct sunlight, bonding your 3D printed parts with superglue isn’t precisely the best course of action due to the drawbacks involved with using superglue possibly causing the bonded pieces to separate.

Polyurethane Glue

Yet another type of glue you can use to join your 3D printed PETG parts is polyurethane glue, which, similarly to superglue, is also one that sees a wide range of applications in daily life due to its versatility, whether it’s bonding wooden pieces together for woodworking projects or performing repairs on kitchen items, making it highly likely that you already have a bottle of it laying around your home.

polyurethane glue


When using polyurethane glue to bond your PETG 3D-printed parts together, the main benefits you will notice are reliable gap-filling, which will ensure that the parts bond reliably with each other regardless of whether there are irregularities or gaps on the surfaces, a high level of flexibility, which will make it possible to bond parts that lean more toward the functional side of things where elasticity and impact resistance is necessary, and longer open time compared to superglue, which will provide you with more time to get the application right.

On the other hand, the drawbacks of using polyurethane glue for your PETG prints are the expansion of the glue during the curing process, which can possibly disrupt the dimensions and the visual quality of the parts you’re bonding in cases where you unintendedly use too much glue (or improper application of the glue), longer drying times, which usually fall into the range of 24 to 48 hours, and non-clear curing, with the glue turning into a yellowish color once it cures.

Considering the benefits and the drawbacks, we can say that polyurethane glue is a fantastic choice for cases where you’re looking for a mix of versatility, ease of use, and strength, with examples such as functional prototypes and DIY projects coming into mind as some of the common usage areas where you can feel free to use polyurethane glue to get the job done.

On the flip side, for projects where quicker assembly, a higher level of precision and dimensional accuracy, or better visual quality with no glue lines visible at all is necessary, you will be better off using a more suitable alternative for the task, such as superglue, as the negatives of using polyurethane glue will outweigh the positives in these cases and produce a suboptimal result.

Two-Part Epoxy

While two-part epoxy also comes with a wide variety of usage areas, similar to superglue and polyurethane glue, which we have discussed earlier, we can consider it to be a more “specialized” type of adhesive in the sense that its application often requires a specific set of circumstances, making it less likely for it to be readily available around the house, or for one to have prior experience with it from daily use.

two part epoxy


Choosing two-part epoxy to bond your PETG 3D-printed parts together comes with the strengths of high temperature, UV, and chemical resistance, which makes it the perfect choice for outdoor applications where the printed part will most likely be susceptible to direct sunlight for extended periods, high tensile strength & long term stability, which ensures that the two parts will remain bonded to each other permanently even under stress, and an even longer open time than polyurethane glue, which makes it possible to apply the adhesive in a more precise manner.

On the other hand, the downsides of using a two-part epoxy for the task at hand are the extended curing times that can go up to several days, which makes it unsuitable for projects where time is limited, the need to mix two components to prepare the adhesive, which complicates the application process and can even lead to issues such as reduced strength & discoloration, and messy application, which can require some trial & error to get right if you don’t have prior experience.

With these strengths and weaknesses in mind, we would recommend considering two-part epoxy as the adhesive of choice for projects where the strength, resistance, and longevity of the bond are absolutely the most critical factors, with examples such as load-bearing components and replacement parts that can be exposed to a multitude of factors ranging from heat to chemicals coming to mind.

On the flip side, for cases where you need to get the parts ready quickly and easily, without too much need for the strongest bonds possible, refraining from using two-part epoxy and considering one of the alternatives that are more suited for the task would be the best way to move forward, as using two-part epoxy would be excessive in such scenarios anyway.

Hot Glue

While it’s a valuable tool in many scenarios, hot glue, similar to two-part epoxy, is another adhesive that we can’t exactly consider to be a household staple like superglue and polyurethane glue due to its usage areas being particular for the most part, whether it’s temporarily assembling parts for prototyping or creating handmade crafts, which makes it less likely for one to have prior experience with it.

hot glue


Using hot glue to join your PETG 3D-printed parts together will offer you benefits such as quick drying, with the glue usually taking no more than a few minutes to cool down and harden, which makes things convenient if you’re in a hurry, ease of use, with glue guns being pretty straightforward to use without the need for prior experience, the capability to apply the glue to any surface regardless of irregularities, which removes the need to prepare the surface first, and a decent amount of flexibility, which makes it suitable for functional parts that require some level of elasticity.

On the other hand, you will also come across some disadvantages with this method, such as a low level of strength, which makes the usage of hot glue unsuitable for functional parts where load-bearing will be necessary, and limited temperature & chemical resistance due to the glue softening and weakening the bonds when exposed to high temperatures & other environmental factors, which makes it unsuitable for outdoor applications.

With everything in mind, we can consider hot glue to be a suitable choice for 3D printing projects where you need to first and foremost bond the parts quickly and easily, even though it will be at the expense of strength and durability, with examples such as architectural models, prototypes, and figurines coming to mind once again in a similar fashion to using superglue for the task.

On the flip side, for projects where a strong and durable bond is absolutely critical for the 3D printed part to be able to fulfill its duty, we would recommend staying away from hot glue and leaning toward an alternative such as polyurethane glue or two-part proxy based on your needs, as it’s highly likely that the hot glue will end up failing and lead to a scenario where the bonded parts end up separating.

3D Pen

While it’s not an adhesive in the traditional sense, unlike all the alternatives we have discussed so far, a 3D pen loaded with PETG filament is a tool that’s perfectly capable of bonding your PETG 3D-printed parts together alongside its standard purposes of designing and prototyping, and while it wouldn’t make a whole lot of sense to purchase a 3D pen for this task alone, it’s an option to consider if you already have one at hand.

3d pen


The primary benefits that will stand out when using a 3D pen for the purposes of bonding the parts together are the high level of control that you won’t get with any other type of adhesive, which will come in handy in cases where a precise application, such as when you need to work with intricate parts, is necessary, color matching, which will practically make it impossible to tell that the two parts are glued to each other when you use a filament of identical color, and a high level of bond strength, which will ensure that your part retains structural integrity.

On the other hand, the downsides you will come across when bonding your PETG prints with a 3D pen are slowness during application due to the amount of plastic that can come out being quite limited with long wait times for the filament to melt, the high cost of filament in comparison to adhesives, and the requirement of prior experience to be able to operate the 3D pen correctly, which can require some extra time if you have never used one before.

Considering these benefits and downsides, we can say that it would be appropriate to utilize a 3D pen for bonding your PETG prints in cases where you’re working with small and delicate parts, and therefore require precise application, especially if it’s critical to maintain a high level of visual quality for your project, with examples such as figurines, trinkets, and gadgets coming to mind.

On the flip side, in scenarios where you’re working with larger surfaces that will naturally require the usage of a large amount of adhesive for the parts to bond strongly to each other, using a 3D pen for the task definitely won’t be the best option out of all the alternatives we have discussed so far due to the downsides we have covered earlier in this section, with traditional adhesives being more suitable for the task.

Conclusion

While there’s a lot that goes into reliably gluing a 3D-printed PETG part, whether it’s to another PETG part or a completely different material, choosing the correct glue is the most vital step of the procedure to ensure that things work out as intended, with the two parts strongly bonded with each other after the gluing process.

As this is yet another case where trial and error will play an important role (like most things in 3D printing), considering that how potent a particular type of glue is can even show differences across distinct brands, our recommendation would be to try a few different products to find out the one that produces the best results for you, which is the only way to ensure that your glued parts are as robust as possible.