How to glue PLA? 5 ways to do it

In this article I’ll share my secrets and tricks to glue PLA. When I came up with the idea of writing this post I didn’t even know that there were so many ways to do it, but remembering different ideas, experiments and videos, I’ve managed to bring together 5 different ways to do it.

Are you curious to know what these 5 techniques are? Read on. 👇👇👇

How to glue PLA with adhesive

The easiest way to glue PLA for most cases is to use an adhesive, so the question is, what kind of glue can I use? We have used several types of glue and we can recommend the ones that have worked for us: cyanoacrylate and special adhesives for plastics.

Cyanoacrylate glue is usually the best choice for bonding PLA parts. Any brand will do. I prefer it on small tubes so it won’t spoil if I don’t use it in a while.

What adhesives to use for PLA?

  • Cyanoacrylate. Cyanoacrylate is the technical name of the adhesives we know as Gorilla Glue, Loctite, SuperGlue, extra-strong glue or instant glue. It is a glue that works for everything, including PLA; it allows to bond it in an easy and fast way with an adhesive that almost all of us have for our home or workshop.
  • Plastic adhesives. Many brands of adhesives sell specific adhesives for plastics, because generally these are a little difficult to glue. I have personally tried UHU for hard plastics, but there is nothing to envy about bonding it with a more typical cyanoacrylate glue.

Glue PLA with epoxy

If you decide to glue the PLA pieces with epoxy you will have 3 extra advantages:

  • You’ll get a stronger bond than with conventional adhesives and glues.
  • You can fill small gaps if the two bonding surfaces are not flat enough or cracks remain.
  • You can also use epoxy to improve the surface finishing with the epoxy smoothing technique (apply an external layer to the part to remove 3D printing layer marks).

But you will have to endure the main disadvantage, which is that preparing, manipulating and applying epoxy is much more complicated and has to be done in a space that you don’t mind dirtying and well ventilated so as not to breathe the gases it gives off.

A lot of epoxy resins are sold to smooth 3D printing parts and any of them will help you to glue your pieces: you will kill two birds with one stone. The most famous product I have tried is SmoothOn’s XTC-30 resin. For both gluing and smoothing, you will be able to use any epoxy resin with the proper consistency (which allows you to apply it with a brush to work the piece for 10-15 minutes).

XTC-3D epoxi
This is the XTC-30 epoxy, which is used for both gluing and smoothing PLA parts. As you can see, the packaging is terrible, but the product works well

Using a hot glue gun

The hot-melt glue gun is an essential part of any workshop. It is suitable for making quick joints, covering gaps, gluing cardboard, insulating electronic components… You won’t get the prettiest bonds, but for prototypes and areas that are not seen, it’s the fastest choice.

PLA can be glued with hot-melt adhesive; the only thing we have to take into account is that from 60-70 ºC the plastic begins to soften, so we have to be careful not to melt the areas of the pieces that we are going to bond.

This is the hot-melt gun that I have, a Parkside gas model. You can use a gas or electric pistol, the only difference is that it warms up a little earlier and can be carried around the workshop without worrying about the cable.

Glue PLA con acetone

Glueing PLA using acetone is an experimental technique that I discovered in the following video of Thomas Sanladerer, one of the most famous 3D printing youtubers.

As you’re going to see, the initial intention of the video was to smooth the PLA pieces with acetone, but the result is not very satisfactory. However, the surfaces of the pieces soften enough to allow them to stick to each other. You can use acetone to join large flat surfaces of ABS.

The Dremel’s technique for PLA welding

This technique doesn’t require glue or any other material: it consists of friction welding the PLA using a Dremel or any other rotary tool. A piece of filament is inserted into the Dremel’s mandrel and rotated in contact with the part so that the filament, melted by friction, fills the gaps and bonds the PLA parts.

I’ve been able to personally try this way of gluing PLA but it doesn’t quite convince me: it’s a bit messy to do (you have to stop and change the filament every time you spend it), I didn’t get a good bond or a good finish.

Perhaps for projects where you have to fill some cracks, it may be worth it, but I do not find sense to weld the pieces in this way instead of using any of the other methods.

Did you like the article?

You can’t say I haven’t given you options, you already have 5 different ways to glue your PLA parts!

If you’ve come this far, you’ve been interested in what I’ve told you. You can help me by leaving your opinion in the comments. I reply to everyone!

Read you later.

6 thoughts on “How to glue PLA? 5 ways to do it”

  1. I’ve seen youtube clips where the used woodglue on not to smooth PLA surfaces… clamped for 48 hours also provided nice results…

  2. Similar to the ‘thermal welding’ I ‘weld’ with a small bernzematic butane soldering iron. I ‘lead’ the filament about 3-4 mm, so that both sides of the print gets to a semi melted temp, and then the wire fuses them together. It ends up welding more like brazing than friction welding. I find that it holds things together pretty well, but I then go back and add some 2 part epoxy on top.

  3. Very helpful. Thank you, Paul. Think I’ll try the cyanoacrylate glue for broken pieces and the XTC-30 epoxy for improving appearance and strengthening.


Leave a Comment