How to Join & Fuse Filament Spools – Combine, Weld, Splice
Reading Time: 6 minutes Joining and fusing filament spools can be difficult, especially when you can’t secure a bond between them. Many users have experienced this issue, so I decided to write this article explaining different methods for joining filaments.
To join filament spools together, you can use a filament joining tool such as a piece of PTFE tube and a candle to heat the two ends of filament and join them within the tube. It’s possible to weld the filament together using a lighter and some careful movements with the filament.
Keep reading to learn the detailed solutions and related information that will help you to join and fuse filament spools.
How to Combine Filament Spools Together
Here’s how to combine filament spools together:
- Join both ends through a PTFE tube
- Connect filament using a heat gun
- Soften filament with a candle flame and join
- Use a filament splicer
Let’s go through each method in detail.
1. Join Both Ends Through a PTFE Tube
One of the methods for joining filament without the use of special tools is to use a Teflon tube.
Cut one tube end and use a candle to create a sharp edge by heating the filament. Repeat for the other filament and then stretch and cut both filaments and insert them into the Teflon tube, which will fold down automatically when the filament reaches the extruder.
One user said it took ten tries to get the temperature right, but after following this method, he was able to join filaments perfectly every time. Just remember to avoid pushing the melted pieces together outside the tube, as it will create a mess.
Instead, quickly insert the tips inside the tube and shape the filament by pushing from both ends and wait 10 seconds for the splice to cool before sliding the tube away for a perfect join.
Another user stated that he had no idea what to do with his scraps until learning about this method. Other users stated that while the method works really well, it can take some time to get it right.
Check out the video below for detailed instructions about this method.
2. Connect Filament Using a Heat Gun
Another method of fusing filament spools together is using a heat gun. To start, prepare the filaments by cutting the ends at an angle and then overlap the two angled ends by about an inch and hold them together.
Users recommend getting the SEEKONE Heat Gun, which is available at Amazon. It can go from 50℃ to 650℃ and it is made from high-quality materials.
- 【Strong Power With 2 Modes】 SEEKONE 1800W heat gun provides strong power quickly heat up to 1202℉(650℃) in 1.5 seconds. Two modes: I: 50-450℃, 190-210L/min; II: 50-650℃, 250-500L/min
Prices pulled from the Amazon Product Advertising API on:
Product prices and availability are accurate as of the date/time indicated and are subject to change. Any price and availability information displayed on [relevant Amazon Site(s), as applicable] at the time of purchase will apply to the purchase of this product.
Apply heat to the overlapped section of the two filaments using a heat gun and then move the heat gun back and forth along the joint, melting the plastic and fusing the two filaments together.
Make sure not to hold the heat gun too close to the filaments or for too long, as this can cause the plastic to melt or deform. Once the joint is fused, gently pull on the joined filament to test the strength of the bond and trim any excess plastic from the joint if necessary.
One user said he found a solution to avoid filing down the joint by just heating the joint and pulling a little bit to reduce the diameter.
Another user who always has about 50g of leftover filament when printing got recommended this method to join all his leftover filament in one long strand. https://www.reddit.com/r/3Dprinting/comments/fu01rc/any_way_to_join_filament/
Check out the video below for a detailed demonstration of that technique.
3. Soften Filament with a Candle Flame and Join
Another method for splicing filament spools is to use a candle flame. To begin, cut the broken end of the filament and the end of a new filament at a sharp angle. Then, overlap the two filaments by about an inch and hold them together.
Next, carefully move the overlapped section of the two filaments over a lit candle flame, making sure not to hold the filament too close or for too long to prevent excessive melting or burning.
Move the joint back and forth through the flame to melt the plastic and fuse the two filaments together. Once the joint is fused, use pliers or scissors to trim any excess plastic from the joint.
One user recommended sanding the sides of the hole with high-grit sandpaper, like 500-600, to get rid of any rough edges. You can use something like the YXYL 48Pcs Sandpaper Assorted Grit 120-5,000 from Amazon.
- Meets All Your Needs: 48 pcs sand paper kit, 16 grits sandpaper assortment, including 3 sheets of each grit: 120, 150, 180, 220, 240, 320, 400, 600, 800, 1000, 1200, 1500, 2000, 2500, 3000, 5000 grit sanding paper
Prices pulled from the Amazon Product Advertising API on:
Product prices and availability are accurate as of the date/time indicated and are subject to change. Any price and availability information displayed on [relevant Amazon Site(s), as applicable] at the time of purchase will apply to the purchase of this product.
Check out the video below for more information about this method.
4. Use a Filament Splicer
Using a filament splicer is another method of combining filament spools that some users suggest for saving filament and avoiding mid-print interruption.
To start, cut the end of each roll of filament at a sharp angle, and overlap the two filaments by about an inch. Then, use the filament splicer to fuse the filaments together, being careful not to overheat the plastic.
You can go with something like the 3D Printer Filament Connector Gen2 from Amazon. It’s simple to use and allows you to join filament together with ease. Just let the splicer warm up for 3 minutes, then while it’s warming up, cut the end of the filament nice and straight.
- 1. This is a patented product newly developed by a team of 3D printing enthusiasts to help connect 1.75 mm filaments of same or different materials.
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Product prices and availability are accurate as of the date/time indicated and are subject to change. Any price and availability information displayed on [relevant Amazon Site(s), as applicable] at the time of purchase will apply to the purchase of this product.
Then you can turn off the splicer and open up the clamp to insert both ends of the filament in. After that, close the clamp and push the filament to the other end until you feel them touch.
Make sure to let the filament cool down for around 5 minutes and sand off any strings on the filament. One user was starting to accumulate partial rolls of filament and found that combining the leftovers from each roll allowed him to make nearly a whole new filament rollover time.
Check out the video below to see how this filament connector works.
These methods should help you to join your filaments together so you don’t have to let them go to waste or just sit there without being used.
