How To Bond 3D Printed Parts // 3D Printing Guide and Tutorial

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hey I'm Alec and today I'm gonna show

you how to bond your prints together so

a lot of 3d printers have build volumes

that are usually smaller than some of

the bigger models that you want to print

whether it's a mini-nuke

or a jet engine those are just a little

too big to print on most printers and

even if you could well sometimes they're

not going to turn out too well

whether it's support on a face that's

going to be visible to somebody so if

you had this printed this way well now I

gonna have supports all over this and

it's not gonna be very pretty

so what you can do is you can split up

your model into a bunch of smaller

pieces and then go about gluing them

together now there are different ways to

glue them together depending on what

material you printed it in and most of

them have some level of chemical noxious

mists and you're gonna want to be just a

little careful with what you're using

but then of course once you glue them

together you're gonna want to find a way

to blend them so you don't really see

those seams so I'm gonna talk about how

to actually attach them and then what

you can do after they're attached and

make those seams kind of go away so

first off no matter what you're doing

you're gonna want to rough up the

surface of the two pieces you're going

to adhere together so if you have two

objects make sure to sand it down and it

doesn't have to be high grit like 40

grit like 220 is enough you just want

more surface area for your adhesive to

bite into and then you can actually put

those together and let it sit and cure

but that's gonna give you a much

stronger hold than if you tried to glue

together a very glossy PLA print it's

just a little too glossy for it to have

such a good hold on it so first off is

everyone's favorite super glue

now it's called cyanoacrylate but what

makes it really versatile is that you

can get it in a ton of different

viscosities so whether it's a gel or so

thin it's like water there are a lot of

different uses for those so if you're

trying to get glue into very thin parts

where you can't get this gel to run use

some liquid stuff and the little goes a

long way because once it goes in there

the surface tension will try and wick it

all the way through the scene so if

you're doing something like a mini-nuke

where this red piece is actually

separate than the rest you have a nice

big face to do it on so you don't have

to use something super runny whereas in

the case with some of this jet engine


I needed the runny super glue to get

really in there between all the little

crevices to kind of

it all together so you just want to make

sure when you're using superglue that

you you are mindful of where it's gonna


because once it flows either you're

gonna have to sand it off or if you

didn't plan to sand it well now you have

a big drip running down the side it on

top of that it does tend to be harder

than the actual plastics so the more you

sand it the more you're gonna wear down

the plastic and the less that the super

Lu's gonna wear down so you'll need to

kind of sand down the superglue and then

build up the part now depending on what

the model actually is it might be

helpful to use a crafty pen so if you

take that 3d printing pen and you feed

in some filament the same type that you

printed your part in you can actually

use it to physically weld together the

two parts in the same material so if you

print together a helmet and you want to

print it in a couple pieces because

there's no way to fit a head size model

on a bed well you're gonna need to put

those back together if you use the

crafty pin you can both melt together

the two halves and backfill it with more

material and you're not going to see

that side of the part so it doesn't

really matter now if it were something

like the mini nuke again all of the

phases of this are visible so if you use

the crafty pen on this you'd have to try

to find a way to make it just look like

natural welding lines or something like

that so with the crafty pen it's really

useful as long as it's on the back face

of whatever your part is so jb weld and

5 min epoxy are really useful too now

both of those do have a cure time which

just means that it's not like super glue

where you'll apply it wait 30 seconds

then it's done it will take some time

for it to achieve full strength so once

you apply the two together you will want

to let it sit around for awhile and even

the 5 minute epoxy I recommend leaving

for a couple hours just to give it that

time but I find 5 minute epoxy works

really well for me when I have like an

armor part that I want to go together so

I'll use superglue - what together the

two pieces but then apply 5 minute epoxy

along the back and that just gives it

more strength and rigidity so it's not

gonna break if I bump into something and

it's just gonna give it that much more

strength when I'm wearing it now

depending on the material you can also

solvent weld it and that just means the

physical material is reactive to a

chemical and so when you apply that

chemical it makes it sort of dissolve

and then you can apply those two

services together and they'll melt back

into one part so it's all the same

material there's no adhesive in there

you're just basically melting the faces

and making them go back together but

sort of what we did here with tracers

gun so this top piece is vapor smooth

but some of these parts are abs so to

weld them all together rather than using

superglue we used a little bit of

acetone and with mixed with a little bit

of ABS and then we just brushed it

between some of the seams and then we

really clamped it together and then it

cured together as one piece so it's it's

a lot stronger this way than just using

regular superglue because it's all the

same material at this point now this

mini nuke was printed in poly smooth

which is pvb and isopropyl alcohol

so you could rub a little isopropyl

alcohol on both sides and then you could

squish them together and it should hold

pretty well and that actually happened

with a couple parts where I took them

out of a polisher a little too soon and

then they they welded together as I set

them aside

oops so reprinted them but using a

solvent is is a really strong way to

hold two parts together if you can

now PLA is nonreactive so you will have

to use superglue for that if you plan to

paint your model there are certain

options to blend the seams together but

if you want it to be just the raw

printed part there isn't a lot you can

do unless it's solvent reactive like I

said before and then you can mix up a

little bit and try to use it to melt the

seams together and sand it back down but

by sanding the part you're also going to

make it stressed which will cause it to

whiten and so there's just gonna be a

lot of trial and error and back and

forth to get it apart to look good and

be the original color but if you're

gonna paint it anyways then you can go

and use body filler bondo glazing putty

or filler primer to really get that part

looking perfect and that's what I did

with the mini-nuke so I did a lot of

sanding I used a little bit of bondo to

patch some of the small parts but you

just mix it is if the ratio is says on

the side of the can and just lightly

feather it across the surface sand it

down until the seams gone and it'll take

a couple tries of building it up and

sanding it down and applying a little

glazing putty to fill in the little

pockets or the very tiny places that

don't need a ton of bondo it's just a

really small divot but it's a lot of

work and that's where a lot of prop

makers a lot of models

shoes spend a lot of their time because

it's it can get pretty intensive trying

to sit there and really get that part

looking shiny and glossy because even a

regular 3d print something like this you

can feel the polygons but if you tried

to blend this and you spent a lot of

time on it you could get it looking

awesome so if you've been 3d printing

for a while a lot of this is gonna seem

familiar but I hope that at least one

thing in here was new to you now if you

feel like there's some technique

adhesive blending option that I didn't

mention here feel free to leave it in

the comment down below I do a lot of

finishing works so if there's anything

new out there that I haven't heard of

I'd love to hear it from you guys I'm

out formatter hackers thanks for

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