Will standard stationary glue work (Elmer's, Kokuyo, or similar), or does something stronger need to be use? Additionally, I also need to glue in magnets into my 3D prints. What is the best kind of glue for this use case, or will any do fine?

They will only be used for a few prints, so I would like to avoid very large containers. Small bottles and syringes are ideal

edit: I will probably go with cyanoacrylate (CA) glue then. 3D Gloop has also been recommended, but is not sold by any local retailers and international shipping will take too long for the project I need to use it for. Could be a neat option for some people though. Thanks, everyone!

Somebody has also suggested acrylic/plastic cement for chemically joining plastic parts together, but in my experience with laser cut acrylic, it's difficult to apply and can also affect the appearance of the print if you mess up. It also has a very short time window between application and fusing. I'm sure it works fine, and it will probably hold up better due to the plastics being chemically fused, but I will go with CA glue.

Sci-Grip 16 for bonding PLA together. Sand the side of the magnet you are gluing in and use Cyano Acrylate (super glue).

Regular superglue for placing magnets, I like 3DGloop for sticking prints together

PLA to PLA: Gloop https://www.3dgloop.com/shop/pla-gloop

I don't know sci-grip, does it leave white marks like super glue?

Acetone dissolves PLA. You can use it for chemical polishing but also for assembling parts.

Super glue is fine. You don't need to waste money on expensive glues.

It's so good that recovering magnets from prints I've made takes a lot of work because the super glue holds them to pla really well.

CA glue (aka super glue) works extremely well with PLA. I wouldn't recommend any special 3d print specific glue because it will probably be the same thing but with a higher price.

Its acrylic based but very thick. So it would leave white marks but it's not going to get all over easily.

Since when does acetone dissolve PLA? For PLA one should use ethyl acetate or chloroform

Cyanoacrylate, aka CA glue or superglue, is the best adhesive for PLA. After applying the glue, fixture or clamp together the parts you are planning to adhere and then leave them alone while the glue cures.

I know this isn't strictly an answer to your question, but maybe something to consider:

I have a hot-air soldering station with different nozzle sizes, one of which is very small. It can be precisely controlled up to 480°C, and it's awesome to weld PLA or PETG together. I stopped using glue alltogether.

You can buy CA accelerant which dramatically reduces the curing time of super glue.

I've been told that methyl ethyl ketone is a good solvent for PLA (similar to acetone and ABS).

You're thinking of ABS/ASA, acetone does not dissolve PLA.

Totally. I prefer to have a little cure time to get things set and aligned properly, for some reason it nakes me feel panic-y when the set time is super quick lol.

I used acetone to chemically-polish a PLA part this very afternoon. But if you say so 🙂

Have you even tried it instead of talking out of your ass?

I use acetone to assemble PLA parts and polish them all the fucken time.

MEK can be a great solvent, but also rather toxic. Not something you want to be working with without gloves and ventilation. Guy on a paint crew I worked with called it "methyl ethyl killya".

You can also mix in baking soda to drastically increase the strength of the bond

This is correct and MEK shouldn’t be recommended to home users not accustomed to working with solvents safely.

https://www.sciencedirect.com/book/edited-volume/9780815515814/handbook-of-plastics-joining pirate this and read chapter 17 it's really valuable

I actually prefer other kinds of fastening for pla. Magnets can be melted into undersized holes via a soldering iron (just avoid cooking too hot, keep it around 100 degrees).

Push fits and friction welds work well in certain applications.

You might get some minor surface reaction, but you're sure as hell not able to dissolve PLA in acetone. Leaving a part printed of PLA in acetone will not turn it in to goo like it does with ABS/ASA.

you’re sure as hell not able to dissolve PLA in acetone

Why don't you try it before saying that?

$35??? No thanks.

I set this up a good 25min ago, let's see what happens. It's polymaker polyterra PLA, 3 walls, 15% gyroid infill and some fuzzy skin with default parameters from orca slicer.

So far all I have is very slight color leeching out, but nothing has dissolved so far. I'll let it run for a few days and keep you updated.

This is Prusament PLA dissolving in acetone in seconds:

I'll come back to it in 30 minutes and it'll be a messy soggy half-dissolved thing. And it'll be fully gone within the hour.

Interesting if that happens, but that seems to be caused by additives used by prusa in their filaments then, because from a chemical standpoint the crystalline structure of PLA is simply not dissolvable by acetone. It can cause swelling and delamination of layers, but not actually dissolve it (without additives that mess with the polymer chains)

Melty melty...

caused by additives used by prusa in their filaments

I'll drop Ultrafuse PLA PRO1 in the jar when this one is gone. It does the same thing

I'm not actually seeing it dissolving at all though. It's softening, sure, but it's not dissolving like ABS does.

CA accelerant also acts as a primer. It's a fucking life changing superpower!

I used to hate CA, except for some applications, but using accelerant makes CA much more viable.

Friction welds sound pretty interesting. I'm guessig only on round joints?

If you have a vibratory tool you can join whatever since PLA melts so low but round shit you can put in a chuck will weld with a drill. They do wear down a bit though, so you need some extra material and you stop when it's in the right place.

Sorry I was busy at work and I left it there.

It's all gone. It just left a bunch of chunks behind - more than usual:

The acetone is black, and when it dries off, it leaves white plasticky powder on my hand.

How much?

Woah, do you know why this works?

The baking soda catalyzes the CA polymerization by dropping the pH.

MEK is dangerous.

Man, you really like to double down on wrong.

Sure you do.

An application of hair dry heat will make the white marks go away.

I just sprinkle it on, if it's too much it can just be blown off.

It also helps to add structure to the bond. The baking soda can build up and add strength.

I use the starbond brand 'super fast thin high performance super glue' and it works really well, but damn, you really don't want to get that on your fingers, it's a pain to remove.

I haven't used it on big prints, but for small models, tabletop terrain, and fixing miniatures it's been great.

Chemistry! (Beyond that, I’m not sure)

Have used this technique to recover color from brim pilling but didn't know it would work in that case too. Thanks :)

Thanks to this discussion I was tempted to try: I can't say if you can fully dissolve PLA in acetone, but you can definitely use acetone to glue PLA pieces together. Actually sticks very well. I'm amazed. Not sure if works for all PLA filaments though ?