Can You Splice 3D Printer Filament? How To Join 3D Filaments!

Almost half of all 3D printers in use are filament printers. The popularity of filament printing is largely due to how easy filament is to use and the wider selection of filament at your disposal. 

So, Can You Splice 3D Printer Filament? How Do You Connect Two Pieces Of Filament!

Connecting two spools of filament becomes necessary when printing a large print and the standard 1kg size roll of filament is not enough. Another less common use is when creating a multicolored print. In both cases, the filament can be joined together by splicing. Splicing is when the ends of the filaments are fused together to form a continuous roll.

Almost any material can be spliced together as long as both pieces are made from the same material. For example, you cannot splice ABS and PLA together. Splicing different brands of the same material will also likely produce poor results. Source

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In this guide, we look at a couple of techniques that can help you reduce filament waste and repair your prints. Splicing and welding are used to join filament and 3D prints together. But how do either of these techniques work? What other methods can you use to join pieces together?

How Do You Use A Filament Splicer?

Splicing can be done either with tools designed specifically for fusing filament or with an improvised tool. Splicers, joiners, and fuse blocks are the least expensive tools. Improvised DIY tools are the cheapest splicing solution. 

Filament splicers work like a vice. You feed the different ends of the filaments that will be spliced together after heating them with a heat source such as a lighter or small torch. Once they come into contact they should then fuse. 

Fuse blocks work like splicers. The only difference is that instead of heating both materials that will be spliced, you only heat one. 

Filament connectors are the most expensive solution for splicing. The reason why they are more expensive is because they do not require an external heating source. All you do is plug them in and they use electricity to generate the heat required to fuse your filament.

The simplest DIY splicer involves using tin foil and a lighter. Here you simply roll the ends of your filaments inside the tin foil then heat them with a lighter or other heat source. 

Methods to Join 3D-Printed Pieces Together

Joining 3D printed pieces is sometimes necessary, for example in the case of a large 3D print that has been printed in separate pieces. The most effective ways of joining 3D printed pieces are welding, joinery, or through the use of a solvent or an adhesive. 

Printing a large print in components reduces the chances of failure. If your printer has a small build area, it might be the only way you can print a large print. Or you may have been forced to print in pieces after running out of filament in mid-print. In this instance, your print may have failed and you had to restart it by printing separate pieces.

Whichever the use case it is useful to have a few methods you can use to join your pieces together.


Two pieces of plastic can be welded just like how metal is welded. This works best with a 3D pen. All you do is extrude filament in and around the joint. After your pieces have fused you can smooth the piece to completely hide the join. 

If you do not have a 3D pen, a soldering iron can work as a substitute. 


You can also join 3D pieces using connectors. The difference between connectors and welds is that welds are fused directly into the pieces whereas connectors act as independent pieces that snap, slot or lock onto both pieces. 

This means you can remove and disassemble the pieces unlike with welding where the join is permanent. There are several types of connectors including

  • Hinges
  • Pins
  • Snap fits
  • Dovetails

Does Super Glue Work On Filament?

Welding and joints are more advanced methods of joining pieces of 3D prints together. They require more expertise and take up significantly more time. A simpler, quicker method, especially for beginners is to use super glue (cyanoacrylate). 

Superglue is a better alternative to either welding or using joints because

  1. It bonds in seconds. You do not have to spend time melting plastic as with welding or designing and fitting a joint as with joinery.
  2. It produces a strong bond with no visible seam. 

Super glue is not without its disadvantages however as

  1. It can bond with your skin. 
  2. Super glue is a fast curing agent and you have to make sure you align your pieces well if you do not want a poorly joined piece. 
  3. Does not work well with flexible materials. 

There are other types of adhesives you can use besides super glue. These include

  • Acetone for ABS, HIPS, and other materials which dissolve in acetone.
  • Epoxy works with all materials but like super glue, it leaves a visible seam on the flexible filament.
  • Plumbers cement for any acetone-soluble material.
  • Hot glue guns can be used on all materials. 

Can You Change Filament Halfway Through A Print?

3D prints can be paused to allow for filament swapping or if the printer has run out of filament. Once the old or finished roll of filament has been substituted for a new one, the print can be resumed.

Changing filament in the middle of a print is necessary if you are trying to create a multi-color print and your printer has a single extruder. Dual extruders are much easier to create multi-color prints with as they can extrude more than one color at once. 

You can change your filament manually by pausing your printer yourself and then swapping the filaments. Alternatively, you can have the printer pause the print at a point you set using the G-Code.


I am a very well experienced techie civil engineer who's extensively interested in 3D printing technology and even more captivated by the potential of 3D printing livable structures

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