As 3D printing is all about creating a model that will either serve a cosmetic or a functional purpose, sometimes the process isn’t as simple as letting the printer do its job and collecting the object afterward.
While not every single print requires it, post-processing is a significant part of the 3D printing world as it allows us to perfect a 3D printed model to the next level. We can consider techniques such as painting, polishing, sanding, gluing, welding, and many more as post-processing, and a print may require just one of them, or a few, depending on the scenario.
Today, our topic will be gluing PETG filaments in particular, where we will be discovering the best glue types for usage with PETG and how to use them optimally.
So, which glue or adhesive is the best choice for bonding PETG?
There are plenty of great alternatives for bonding PETG, which we have listed below:
- Cyanoacrylate (Superglue)
- Polyurethane Glue
- Silicone Adhesives
As each adhesive has distinct strengths and weaknesses, we will analyze them individually, find out the best use cases, and outline how you can use each of these adhesives with PETG in the next section.
Which Glue (Adhesive) is the Best Choice for PETG?
While there are plenty of great options for bonding PETG, each of them comes with different attributes of its own, which gives us a choice depending on the scenario.
Without further ado, let’s get down to analyzing.
The first type of glue we will be looking at is cyanoacrylate, more commonly known as superglue or CA glue.
The main advantages of cyanoacrylate are that it’s easy to apply and quick to dry.
Superglue usually takes less than a minute to dry and 24 hours to cure fully.
As it’s possible to find cyanoacrylate in both liquid and gel forms, it’s a fantastic option whether you are planning on pouring the glue into the cracks or looking to apply it to a spot.
On the other hand, the primary disadvantage of superglue is that it’s way too brittle, making it not the best option for durability, especially if you are thinking long-term.
Bottom line, cyanoacrylate is a fantastic option for usage in 3D printed models that lean more towards cosmetic than functional, especially if you’re looking for a quick, versatile, and easy-to-apply fix.
As cyanoacrylate does a great job sticking to the plastic, it’s not only a fantastic option for PETG but for PLA and ABS as well.
Next up is polyurethane glue, a glue known for sticking to almost every material, making it a popular option for bonding plastic, wood, stone, metal, ceramic, glass, and many more.
The primary strengths of polyurethane glue are that it sticks to almost everything, creates strong bonds that will stay durable for long periods, and is fully waterproof.
While not as quick as superglue, polyurethane glue still dries relatively quickly with a dry time of 1 to 2 hours and a curing time of 24 hours. In terms of ease of use, polyurethane glue ranks second right below superglue.
The only downside of polyurethane glue is that it’s thick, which will cause your model to be slightly thicker than intended depending on the amount of glue you have applied.
Bottom line, polyurethane glue is the go-to option if you’re looking for something more durable than superglue or planning on using your 3D printed model in an area where it can absorb moisture.
As polyurethane glue virtually sticks to anything, you can also use it to bond PETG with entirely different materials.
Silicone sealants are something we are all familiar with, and they behave similarly to polyurethane glue in the case of bonding PETG for the most part.
The strengths of silicone sealants, similar to polyurethane glue, are that it sticks very well to most materials, creates strong bonds that will stay durable for an even longer time than polyurethane glue itself, and is waterproof.
On the other hand, unlike polyurethane glue, as silicone sealants need to cure before usage, you will need to wait approximately 24 hours before you can put your 3D printed object into use.
While applying silicone sealants isn’t a difficult task, we would rank the ease of use slightly below polyurethane glue as it requires some degree of experience to do correctly.
The downside of silicone sealants is the same as polyurethane glue, which is the thick layer that will reside between the two surfaces you have bonded.
Bottom line, we feel like there isn’t much of a reason to use silicone sealants if you have access to polyurethane glue, as the ease of use and quicker drying time of polyurethane glue easily outweighs the durability advantage of silicone sealants.
Silicone sealants also do a fantastic job of sticking to almost everything, with wood being the exception.
Last but not least, let’s talk about epoxy. While not as popular as the other options, epoxy really shines when strength is the primary concern.
The primary strength of epoxy is its durability, which allows it to withstand a larger amount of force than any other adhesive we have listed earlier.
While it takes a few hours for the epoxy to set, it needs to fully cure to achieve maximum strength, which will take approximately a day.
Compared to other adhesives we have listed above, using epoxy is slightly more complicated, as it consists of two materials that you will need to mix together before application.
Bottom line, two-part epoxy is the best option if you need to bond surfaces for a functionally printed 3D model that will require as much durability as possible.
Epoxy will stick to almost everything, with some exceptions, such as silicone, vinyl, rubber, and wax paper.
Can You Weld PETG Together with Solvent Welding?
While not technically a type of glue, solvent welding is a widely used technique that is quite effective for chemically combining (welding) surfaces.
You can indeed use solvent welding to weld PETG together, which will form stronger bonds than any other type of adhesive (such as cyanoacrylate, polyurethane glue, or even epoxy).
Due to its strength, solvent welding is the best option for 3D printed models that are functional and will be under stress during usage.
As solvent welding directly bonds two surfaces, it adds no additional thickness to the model, making it the best option in terms of aesthetics as well.
While hiding the fact that you glued something can be difficult due to the glue layers, pieces that you have welded with solvent welding will show no such signs.
The downside of solvent welding is that it requires more caution and experience due to the safety concerns that come with it, which is why we highly recommend steering clear of it unless you have prior experience.
If you require the benefits that come with solvent welding but have no prior experience with it, we recommend hiring a professional to solvent weld the pieces for you.
How to Prepare Before Applying Glue to PETG?
Preparing the surface of the model and taking safety precautions before applying the glue is imperative to ensure that the glue sticks as well as possible and there are no health risks involved during the process.
Here are the steps we recommend taking to prepare before applying the glue to PETG:
- Start by wearing a pair of gloves as glue can irritate your skin in the case of contact.
- Ensure that the room you will be conducting the gluing process in is well-ventilated to minimize your exposure to the fumes.
- Sand the surfaces you will be gluing.
- Clean the surfaces after sanding to ensure that there are no particles left on them.
- Degrease the surface to ensure that there is no oil or grease on the surface, as oil and grease can drastically reduce the adhesive capabilities of the glue.
- Read the manufacturer’s instructions to ensure that you apply the glue as correctly as possible.
As there are plenty of fantastic options for gluing PETG, the glue choice mostly comes down to preference and the conditions you have, such as the environment.
Since the glue will be the only thing holding your model together, we highly recommend going with a high-quality brand that won’t give you issues down the road to avoid having to print everything all over.
Finally, remember that the gluing process is as significant as the glue itself, so make sure not to ignore the surface preparation and safety measures before you start applying the glue for the process to go as smoothly as possible.
Mike started his 3D printing journey with the Anet A8 when it first came out back in 2017, and has been obsessed with 3D printers ever since. Nowadays, he primarily uses his Ender 3 to print functional parts that make his life more convenient whenever possible.