Whether you have a failed 3D print or had to slice your model into pieces to fit on your print bed, finding ways to connect two 3D printed pieces requires knowledge of what will work — and what won’t. After all, plastic is a rigid and shiny material that resists most glues.
You can connect two 3D printed pieces using a hot glue gun, super glue, epoxy, screws, bolts, connectors, hinges, inserts, sewing, or soldering iron. While all these methods are effective, some of these ways to connect 3D-printed parts are better for specific thermoplastics.
In this article, I’ll teach you some of the best ways to join two 3D-printed parts. Some of these methods are more common than others, and some work better than others for certain filaments, so let’s explore all the details.
1. Use a Hot Glue Gun To Connect the Pieces
Best For: PLA, PETG, ABS, and filaments with low print temperatures.
A hot glue gun is a staple in most people’s toolboxes, as the glue can be surprisingly strong and flexible. However, in the case of 3D-printed parts, the adhesive isn’t what you want to use. Instead, you want to use the hot glue gun’s heat to fuse your pieces.
For that reason, hot glue will only stick well to plastics that don’t require too much heat to melt. For example, hi-temp hot glue guns usually only reach around 195° C (383° F). So if your filament has a higher heat resistance temperature, the hot glue gun won’t make a strong joint.
Here’s how to use a hot glue gun to connect two 3D-printed pieces in five easy steps:
- The first step is to gather your materials. You’ll need a hot glue gun, glue sticks, and something to act as a work surface. I recommend using a piece of scrap cardboard or something similar.
- Next, insert the glue stick into the hot glue gun and plug it in. Some hot glue guns have a light that turns on when heated.
- Once the glue gun is hot, apply the glue. Only use a small amount of glue, but allow the metal gun’s nozzle to rest on the plastic for a few seconds to soften it.
- Press the two surfaces together firmly for about 30 seconds. That gives the glue time to set.
- Let the glue cool completely before moving or handling the piece. For the best results, give the adhesive 24 hours to cure completely.
And that’s it! Your 3D-printed pieces are now successfully connected with hot glue.
2. Use Super Glue To Connect the Pieces
Best For: Non-flexible filaments like PLA, ABS, and PETG.
Another option for connecting 3D-printed pieces is to use super glue. The method is similar to using a hot glue gun, but it can be a bit messier since it’s difficult to control the amount of glue that comes from the bottle.
Super glue creates a crusty, inflexible bond. Thus, it will only stick to rigid filaments.
However, it’s one of the best adhesives for the most common 3D printing filaments.
When selecting a superglue, choose one with a cyanoacrylate base. An example is Loctite Super Bonder (on Amazon), which most 3D printing enthusiasts use to bond PLA.
Here’s how to use super glue to connect two 3D-printed pieces in five easy steps:
- First, sand down the connecting edges of the two pieces you want to glue together. That will help the glue adhere better and create a stronger bond.
- Next, apply a thin layer of superglue to both surfaces. Be careful not to use too much glue, as that can make the pieces difficult to align.
- Align the two pieces, so they fit together snugly, then press them firmly. Hold them in place for 30 seconds.
- If there’s any excess glue seeping out from between the pieces, use a toothpick or other sharp object to remove it before it dries. Extra adhesive can prolong the curing time and damage the finish.
- Allow the glued joint to dry for at least 24 hours before handling or moving the piece. Patience is paramount here, as putting any pressure on the bond too early could result in a snap – in which case, you’d have to start over again and wait another 24 hours for the glue to set.
3. Use Two-Part Epoxy To Connect the 3D Printed Pieces.
Best For: Resin 3D prints, ABS, PLA, PETG.
Epoxy is another excellent option for connecting 3D-printed pieces. It’s a two-part adhesive that comes in a tube or syringe and sets quickly, making it ideal for large parts or projects where time is of the essence.
Resin offers one of the strongest, most pressure-resistant joints, which is excellent for structural parts that must withstand a bit of tension.
Here’s how to use epoxy to connect two 3D-printed pieces in five easy steps:
- First, wear gloves to protect your hands from the adhesive.
- Mix equal parts of the epoxy resin and hardener in a mixing cup. If you use a syringe of epoxy, squeeze some of the glue onto a disposable surface, like a piece of cardboard or paper plate.
- Use the stir stick to mix the two components until they are thoroughly combined. The resin will turn clear when it’s ready. Be sure to mix thoroughly! If the two components are not fully mixed, the epoxy will not set properly.
- Apply a generous amount of epoxy to one of the surfaces you want to bond.
- Press the two surfaces firmly and hold them in place for 60 seconds while the epoxy sets. It would be best to consider clamping the parts together, as it sometimes takes a little while for the epoxy to cure fully.
- Repeat the process for all the joints you want to reinforce.
- After applying the epoxy, set the project aside and allow the epoxy to cure for at least 24 hours.
Do not disturb the project so the epoxy can fully cure and create a strong bond.
4. Use Screws To Connect the Two Pieces:
Best For: Any filament with 90-degree joints.
Another option for connecting 3D-printed pieces is to use screws. The method is more permanent than glue or tape, but it can be helpful if you need a firm bond between the two pieces.
Here’s how you can use screws to connect two 3D-printed pieces:
- Gather a drill, the two 3D prints, screws, and something to catch the shavings (optional).
- Determine where you want the screws to go. The function of the joint will determine the
- Once you’ve decided on the placement, use a drill to make pilot holes for the screws. If your 3D-printed pieces are small, you may be able to get away with using a small Dremel.
- Feed the screws through the hole using a screwdriver and very light pressure to avoid cracking the plastic.
- If the screw does not seem secure enough, use a hot glue gun to create a permanent “nut,” squeezing the glue onto any exposed threads.
- Tip: Carefully place the end of your drill bit on the mark and begin drilling slowly. Increase speed ideal spot. If it needs to pivot, place the screw off-center, etc.as needed, but be careful not to go too fast, or you may damage the piece.
If you’re concerned about shavings getting everywhere, tape something over the hole before drilling or hold the piece over a garbage can.
5. Use Nuts and Bolts
Best For: Any print with a hollow center.
If you’re looking for an even stronger bond than what screws can provide, you can try using nuts and bolts. The method is similar to using screws, but you’ll also need to use nuts and washers to secure the connection.
To use this method, follow these steps:
- Gather your drill, the two objects, nuts, bolts, and washers.
- Just like with screws, you’ll need to determine where you want the connection to be before drilling any holes.
- Once you’ve decided on the placement, use a drill to make pilot holes for the bolts.
- Next, thread a nut and washer onto each bolt.
- Carefully align the two pieces you want to connect, then insert the bolts through the holes.
- Tighten the nuts with a wrench until the connection is secure. Still, don’t make the joint too tight! You may crack the plastic if you over-tighten it.
Pro Tip: If you have trouble getting the bolts started, try using a drop of lubricant (like WD-40) on the threads.
6. Use Snap-Fit Connectors
Best For: Any print to which you can add a snap-fit connector or that has a 90-degree, exposed angle between the two printed parts.
Snap-fit connectors are connectors designed to snap into place. They’re common in injection molded plastic parts, but you can also find them in 3D-printed parts.
If your 3D print does not have snap-fit connectors, you can use any of the above adhesive methods to print connectors, then glue them in place.
Then, using the connectors, you can create an impermanent joint between your pieces, allowing you to snap and unsnap the parts from each other in the future.
Here’s how to use snap-fit connectors:
- Align the two pieces you want to connect
- Press the two pieces together until the snap-fit connector snaps into place.
7. Use Hinges for Joints That Move or Pivot
Another way to connect two 3D-printed pieces is to use hinges. This method is helpful if you need to create a joint that can move or pivot.
To use this method, follow these steps:
- Gather your drill, the two objects, screws, and hinges.
- Determine where you want the hinges to be.
- Once you’ve decided on the placement, use a drill to make pilot holes for the screws.
- Next, attach the hinges to the two pieces using screws.
Pro Tip: When attaching the hinges, leave enough space so the two pieces can move freely.
8. Use Threaded Inserts
Best for: Any 3D print with thick walls and dense infill.
Threaded inserts are another excellent option for connecting 3D-printed parts. They work by creating threads inside of both pieces that you’re trying to connect. To use threaded inserts:
1. Choose the Right Size Insert for Your Project
The first step is to choose the right size threaded insert for your project. There are many different sizes available, so it is crucial to select the one that best fits your needs.
If you are unsure of which size to choose, it is always best to err on the side of caution and select a smaller size.
2. Drill a Hole in Each Part
Next, you will need to drill a hole in each of the 3D-printed parts you are trying to connect.
It’s also vital to ensure the pilot hole is perpendicular to the piece’s surface so the insert will be straight.
3. Insert the Threaded Inserts
Once you have drilled the holes, you can insert the threaded inserts.
- Start by inserting the insert into one of the holes, and then use a tool to screw it in until it is flush with the surface.
- Use a mallet or hammer to tap it into place gently if it doesn’t want to go in.
4. Connect All Pieces
Now, you can connect all the pieces using screws, bolts, or any other type of fastener.
To do that, thread the fastener into the insert until it is tight.
You can repeat these steps to join almost any 3D-printed part with a wall thickness wide enough to fit a screw.
9. Sew The Pieces Together
Best For: Any 3D printed part that you don’t want a clean joint on
In some cases, you don’t necessarily need a clean finish. For example, I have been printing a spooky mask for Halloween, but it kept failing, forcing me to slice the model into several pieces, then join them later.
Still, since I was going for a spooky look, I used a drill to create holes in the mask, then sewed them together with some pieces of copper wire.
This joint creates a noticeable seam, so it’s not ideal for every 3D print, but it is a great way to add artistic flare to your prints.
So, feel free to get creative and find unique ways to make joints with wire, string, yarn, or any other type of cord.
10. Solder or Weld The Pieces Together
Welding is another excellent way to connect 3D-printed parts. While you could use a high-powered laser to join your pieces, not everyone has a laser welding machine, and getting one would be costly.
So, what can you do? Use a soldering iron!
Soldering irons are inexpensive tools that you can use to create very smooth, simple joints between 3D-printed parts.
To weld the pieces together, take a spare piece of filament and use your soldering iron to melt it into your parts’ joints.
For a detailed explanation and tutorial, check out this video:
There are many different ways to connect 3D-printed parts. The best method for your project will depend on the type of parts you’re working with and the level of precision you need.
Superglue or epoxy is usually the best solution, as these adhesives are cheap, transparent, and durable. However, there are many ways to create joints for 3D-printed parts, so try out a few of the ideas above to see what works best for your prints and your favorite printing materials.
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I started 3D printing since 2013 and have learned a lot since then. Because of this I want to share my knowledge of what I have learned in the past years with the community. Currently I own 2 Bambulab X1 Carbon, Prusa SL1S and a Prusa MK3S+. Hope you learn something from my blog after my years of experience in 3D printing.