I’m looking for some advice on how to bond a post-processed resin printed piece to a large PLA print. I assume my options are either superglue or maybe brushing resin onto the PLA, attaching the resin print, and hitting it with a UV light?
Is there a better way? Thanks!
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You could use just a regular 5 min epoxy. I frequently use CA glue, but depending on your use case, it might be too brittle.
Brittleness might be a concern, it will be for a costume piece
Thank you!
And if you don’t have easy access to 5 min epoxy, you could go with the super glue + baking soda trick for a similarly strong and hard bond: https://gluetips.com/super-glue-and-baking-soda/
Make sure to rough up the resin surface to be glued then use CA glue and send it. I’m sure it will be sufficient.
Rough up both surfaces.
Alternatively, if you want a removable bond, barges. It can be neater (barges is weird. You paint it on both parts after a few minutes, it’ll be not-tacky, but’ll bond to other barges. You can remove it with the application of gentle heat. It’s also flexible.)
Finally VHB tape from 3m is wonderful,
Y, just use a little file and gently rub it over the two places you’re going to be connecting. Then use some E6000 and a clamp. I can’t remember why this is, but I do know that glue tends to stick best when spaced out. Perhaps the roughing up of the area permits for micro-gaps which allow for the two to better stick? Or that smooth faces in general do not stick well to one another. But I do know whenever gluing plastic I just grab a little metal file and always rub it over whatever part I will be hiding with glue.
Perhaps the roughing up of the area permits for micro-gaps which allow for the two to better stick?
I think it is more to do with increased surface area - more molecules of the glue are in contact with the part.
Seems so strange in my head, that you’re removing body yet the surface area is increased? But I actually truly don’t know the science (and actually did not look it up because it’s pretty irrelevant to me). But I do like to look stuff up. I think I just fell down the pie-hole and didn’t take the time. Maybe it’s like a razor, where as you sharpen it and the surface area changes the quality of the shave?
Eh, now I really do have to look into it. Cause clearly you’re saying what it is - I just gotta figure out how you subtract material and it increases surface area. To the internet~
Tada:
Plastic Bonding 101
“It takes the surface from a flat surface to a rough surface. So what was previously flat, now has peaks and troughs. In most cases, an increased available bonding area leads to a stronger joint.”I just gotta figure out how you subtract material and it increases surface area.
Say you have a smooth shape like: ███ That has a nice and simple area and surface area. But if you take a chunk out of it: █▂█ you now have less area, but surface area is the same plus those two new vertical walls - so it has increased. That is basically what roughing up the surface does. Might also do some deformation and add some peaks as well though far less than the material removed.
This all leads into the coastline paradox and fractal patterns which show that you can have a finite volume surrounded by an infinite surface area. Here are some interesting videos on the topic: https://www.youtube.com/watch?v=AD4vPNBSrKY https://www.youtube.com/watch?v=I_rw-AJqpCM https://www.youtube.com/watch?v=gB9n2gHsHN4 https://www.youtube.com/watch?v=3s7h2MHQtxc
I’m so geeked out right now, I can’t even tell you. Thank you human, for these lovely videos. I actually have never heard of any of this outside of fractals, and even then I just know of them. When I was in school I got a taste of discrete mathematics, and nothing alive can signal how little you know than getting even a taste of this stuff. It’s absolutely brain tingling, even if some of that tingle is pain in my case. Hahaha! I love it though, and I thank you for the explanation and these. Off to watch!
I usually use ca glue or a
soldering ironto fuse or repair parts.That said, if you have good ventilation and ppe I know acetone welding is not uncommon for abs and I’ve come across an older post where that works with PLA. Not sure if it’ll work with your resin, could always try with a test piece.OP wants to connect a Resin print to a PLA print, not two Filament-printed models together!
I understand that, acetone attacks a lot of plastics, I’ve seen mixed comments about it with resin prints for smoothing, I don’t see the harm with trying it on scrap material, at worst it doesn’t work.
CA glue though should work, heat won’t so that’s my bad. Op’s original idea of brushing on resin and curing it sounded possible to me.
There’s also mechanical solutions, if possible op could change their parts to accept a screw, into plastic is plenty strong. or they could build in some sort of snap fit solution but both of those would require design changes and I assume op already has their parts printed.
The problem with brushing on resin is actually not that great because resin for printers will need to be cured. Unless that material is letting the UV light through, only the outer parts will get cured and hold onto the models but when you open it up again the whole middle part would be liquid resin again which stinks and is toxic.
I had this misunderstanding for quite a while myself and though that I can just weld resin party with resin together until I did that with a larger piece and it broke quite easily and seeing that the whole inside wasn’t even touched at all by the UV light.
Hence also why you should shine some UV light into a hollowed model to fully cure it.
CA/superglue should do fine if applied correctly.
Totally fair, had thought maybe keeping a thin amount on the edges would enable it to cure correctly.
Definitely agree wrt to CA, you could use epoxy and other adhesives but CA is surprisingly strong, I have some cassette towers that are glued together with it and they’re not going anywhere.
Not super relevant to this but for anyone using CA glue, don’t use it on fibrous material and please wear nitrile gloves, it reacts exothermically with some fibres and produces acrid vapours, it’s really unpleasant, it should be called out on the SDS (which you should always check, there’s enough stuff in most home shops that I’d wager has special precautions for handling and use that people aren’t aware of)
