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.
What adhesives to use for PLA?
- Cyanoacrylate. Cyanoacrylate is the technical name of the adhesives we know as SuperGlue, extra-strong glue or instant glue. Here you can see what I mean. It is a glue that works for everything, including PLA; it allows to glue 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 of parts 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 and there is the Spanish alternative of 3DSmooth. But 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).
Using a hot-melt 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… In general it is not useful to get the most aesthetic bonds, but especially for prototypes and areas that are not seen, it usually takes us out of a predicament.
The 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.
Glue PLA con acetone
Glueing the 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.
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 multirotary 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 in areas of the piece or in which you can then sand, it may be worth it, but I do not find sense to weld the pieces in this way instead of using any of the 3 above.
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You can’t say I haven’t given you options, you already have 5 different ways to glue your PLA parts!
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