Being able to securely stick two (or more) prints together is pretty important. Because a weak bond will make those larger multi-section prints fragile and can ruin your projects.
(Keep reading and I’ll show you how I make ultra-strong bonds every time…)
See, most people go about adhering their prints together all wrong.
Gluing PLA especially seems to be tricky for most people – but what I’m about to tell you will resolve your adhesion issues, for good.
Here’s my best tips (and everything below is naturally after you’ve cleaned both surfaces, free of dust and grease):
1. OK first up – the outright strongest way to stick PLA (and other non-acetone soluble materials) is with superglue. But what if you tried that and didn’t work well for you in the past?
I’m afraid it’s because you did it wrong…
See, what most people don’t realise is that superglue has a REALLY short shelf life. Once opened, after about 25 days it’s just not as strong. Like a month-open bottle of Tabasco sauce, it loses its spice quickly.
So while I hate overly-packaged products, superglue is the one thing I’ll happily buy 3 x 5g tubes rather than 1 big one.
Second tip (aside from making sure the surfaces are clean of course) is basically to use Zap CA – it’s the best I’ve tried. Others probably work OK too, though.
Third tip, use an accelerator spray (if required). And/or mix it with talcum powder to make a strong filler, if required.
2. Need to bond ABS, ASA, PMMA, HIPS or Polycarbonate? The best thing here is usually acetone, as it will dissolve the two materials “melting” them into a solid bond.
Just apply it with a brush to both surfaces, like you would a glue.
HOWEVER – Depending on the material this may not be as strong as the correct, fresh superglue, though. So may be worth doing your own testing here.
3. A great tool that I find indispensable is actually a 3D printing pen. Obviously you use the same material as your prints, so this doesn’t work if you’re joining two different materials.
Heat the two surfaces a little first (with LIGHT application of a heat gun or hairdryer), and apply the melted material to one side before you bond. You want one that has an adjustable temperature, so you can get the right temp for the material you’re using.
I like this method because you have a little more time for adjusting.
4. BONUS TIP: This is my favourite way, because it’s a great combination. For prints that want a really nice AND strong finish on (if I’m sanding down or painting) I’ll superglue the main surface area and then use a 3D printing pen around the join/seam to fill and adhere here.
That way, when you sand it down, you don’t have a differential in material hardness, so you get a seamless joint.
And it has an advantage over filler because I find it easier to apply with the pen into the void (and it’s the same colour as your print).
Note: for ALL these methods, goes without saying to use a very well ventilated area and safety gear.