I'm making a model out of plexi by heating it and bending it. I need to adhere pieces together but I can't use any glue. I've tried melting pieces together but once the plexi returns back to room temp the pieces snap off each other.
Any suggestions on how I can get the pieces to have a strong bond to each other without using glue? Thanks!
I can't think of a way to successfully melt/bond the materials together outside of the already mentioned adhesives, you might want to think about stealing some traditional joinery details to accomplish what you're looking to do. or silicon caulking perhaps? not sure how strong this would be though...
If adhesives are out because it's an assignment - then stop searching for a way to "bond" the pieces and do what pixel suggests and look at joinery or other mechanical methods.
the difficulty of this is perhaps part of the reason the challenge was assigned.
if it's not an assignment, perhaps more information on why adhesives are a problem could suggest a workaround (although I can't think of any)
I can imagine the desired tolerance for clean plexi joinery work is pretty high.
I really need to join your forum, I keep meaning to do that and start pushing it on my students that come through the shop.
please do..... trying to get it going... i have a mini poster that i made that i could send you if you wanna post it in the shop.......
i'll probably start filming some tutorials soon..... sort of put that on the side for a while......
theres also a few tricks for joints if you are using a laser too....... lasers produce a "kerf" to the edge so if you plan it out right, you can use the kerf to your advantage for a friction fit
I'm curious as to why the poster is forbidden (?) to use adhesives.
The typical acrylic joint is made with a specific solvent, applied with a needle-nosed squeeze bottle to the joint while the two pieces are held in position. The solvent fills the joint by capillary action and quickly evaporates, leaving a "welded" joint.
the reason behind not being able to use adhesive: we're working on material studies...and i chose plexi....using adhesive is applying a second material which i don't want to do. yet i'm finding out the further i go along with that idea that it wasn't the best one....ugghh. unfortunately i already discussed the idea of not using adhesive with my teacher and he told me he wanted me to go with that idea.
use an acrylic dowel rod and drill with an "acrylic drill bit" and then use the dowel to secure the pieces together..... assuming that you are stacking the acrylic together face to face...... edge to edge you would need to figure a slip fit or finger joint.....
1/8" i'm melting and bending in areas of the plexi which is working out great...but when i have to attach pieces to each other is where i'm running into the trouble.
Yow ! Phew. . .give me a minute. In the meantime, the graphics of that page are awesome, metamechanic.
It shouldn't be too hard to make :B:'s rod-and-hole into a rivet, perhaps peening one side at a time with the end of a steel rod, heated ? Maybe that was his intention.
Edge-to-face is going to be trickier. A castellated edge, engaging a row of holes ?
My guess is that the assignment only allows you to use plexi-glass for joining? So steel components would be out of the question. In that case I’d agree with the earlier poster who suggested acrylic rods.
If this doesn't work you can pour acrylic from a two part mix that most plastic stores will sell, imagine drilling holes or carving out sections of the two pieces you're trying to join, and then casting another piece of acrylic that permeates the holes in the other two pieces.
If metal is an option, I’ve cast bolts and nuts into liquid acrylic before, so you can simply screw pieces together, that works nicely.
I use to "glue" plexi with chloroform (yes that is the same stuff used as an anestatic in the movies; to press a white handkerchief in somebodies face).
What it basicly does, is melt the plexi and then the chloroform vapourates into thin air. You need to wear safety glasses!!! and you need a needle-pipet to apply the chloroform....
another way is by cutting slots into the plexi, place them together (as if they fit together like a puzzle (vertical into a horizontal)), and then you can melt and bend the 'legs' on each plexi so that they are stable.
working with plexi question
I'm making a model out of plexi by heating it and bending it. I need to adhere pieces together but I can't use any glue. I've tried melting pieces together but once the plexi returns back to room temp the pieces snap off each other.
Any suggestions on how I can get the pieces to have a strong bond to each other without using glue? Thanks!
i believe there are adhesives that fuse plexi together. i think plastruct may make something like that.
ah, there is this.
Thanks...but I can't use any adhesives! I need to join the pieces together with joints (which is hard to do with plexi), or melting...etc...
oh oops, ha ha, i guess i should have finished reading your post!
sorry dude, i don't have much experience working with the stuff to be able to recommend anything.
I can't think of a way to successfully melt/bond the materials together outside of the already mentioned adhesives, you might want to think about stealing some traditional joinery details to accomplish what you're looking to do. or silicon caulking perhaps? not sure how strong this would be though...
If adhesives are out because it's an assignment - then stop searching for a way to "bond" the pieces and do what pixel suggests and look at joinery or other mechanical methods.
the difficulty of this is perhaps part of the reason the challenge was assigned.
if it's not an assignment, perhaps more information on why adhesives are a problem could suggest a workaround (although I can't think of any)
theres alot of materials that people refer to as "plexi"
the shit you buy at home depot with the blue covering on it is garbage...
find a local plastics store and call them
you would need to work with CAST ACRYLIC
there also extruded acrylic but if you can get the cast for larger thickness
cast acrylic doesnt have a grain to it.....sounds stupid right
extruded has a "grain" to it.... you'll see arrows on the papar cover that should tell you the direction of the "grain/extrusion"
if you heat the extruded you will notice the way it will tension up and bend.... you want to bend perpindicular to the "grain"....
depending on the sizes of the pieces..... if you can fit them in a mini toaster oven ......
you can't heat fuse the acrylic either...... it'll bubble .....
look into slip fit connections and finger joints.......
not sure on your shop skills but keep in mind tolerances
i have a forum in my profile that is based for model building/etc....
I can imagine the desired tolerance for clean plexi joinery work is pretty high.
I really need to join your forum, I keep meaning to do that and start pushing it on my students that come through the shop.
please do..... trying to get it going... i have a mini poster that i made that i could send you if you wanna post it in the shop.......
i'll probably start filming some tutorials soon..... sort of put that on the side for a while......
theres also a few tricks for joints if you are using a laser too....... lasers produce a "kerf" to the edge so if you plan it out right, you can use the kerf to your advantage for a friction fit
I'm curious as to why the poster is forbidden (?) to use adhesives.
The typical acrylic joint is made with a specific solvent, applied with a needle-nosed squeeze bottle to the joint while the two pieces are held in position. The solvent fills the joint by capillary action and quickly evaporates, leaving a "welded" joint.
the reason behind not being able to use adhesive: we're working on material studies...and i chose plexi....using adhesive is applying a second material which i don't want to do. yet i'm finding out the further i go along with that idea that it wasn't the best one....ugghh. unfortunately i already discussed the idea of not using adhesive with my teacher and he told me he wanted me to go with that idea.
So, the limitation becomes the inspiration: as mentioned above, different kinds of mechanical fitting can be explored, and will drive the design.
Let us know what happens ! SDR
use an acrylic dowel rod and drill with an "acrylic drill bit" and then use the dowel to secure the pieces together..... assuming that you are stacking the acrylic together face to face...... edge to edge you would need to figure a slip fit or finger joint.....
how thick is the material?
1/8" i'm melting and bending in areas of the plexi which is working out great...but when i have to attach pieces to each other is where i'm running into the trouble.
can you post a pic....... have a digital cammy and use photobucket then post the link......
are you going end to end or over lapping faces or edge to face/etc
Yow ! Phew. . .give me a minute. In the meantime, the graphics of that page are awesome, metamechanic.
It shouldn't be too hard to make :B:'s rod-and-hole into a rivet, perhaps peening one side at a time with the end of a steel rod, heated ? Maybe that was his intention.
Edge-to-face is going to be trickier. A castellated edge, engaging a row of holes ?
Let's see what you are building, if possible.
My guess is that the assignment only allows you to use plexi-glass for joining? So steel components would be out of the question. In that case I’d agree with the earlier poster who suggested acrylic rods.
If this doesn't work you can pour acrylic from a two part mix that most plastic stores will sell, imagine drilling holes or carving out sections of the two pieces you're trying to join, and then casting another piece of acrylic that permeates the holes in the other two pieces.
If metal is an option, I’ve cast bolts and nuts into liquid acrylic before, so you can simply screw pieces together, that works nicely.
things that need to addressed....
size of pieces
connection conditions
usually acrylic rods are just a tad bigger than the drill bit size..... you'll have to double check that though....
if the rod is larger you can rough sand it to get a strong enough friction fit....
this was all pressured fit
http://www.237am.com/portfolio/index.asp?Cat_ID=7
Your model transport case, and metallic portfolio case, are wonderful and mad.
Is that a vehicular model, visible at the bottom right ?
Don't stop now !
my 77 vette?..... it's my summer ride....hahaha.......
in the transport case bottom right that was a section/frame of the model that was above it... the rib design .......
you could do a plexi rivot..... get some acrylic tube and then use a finish head nail and the "plunger" to pull through it..... not a bad idea
would have to plunge both sides though....would have to heat up the nail too....
better yet use a roofing nail so you can get a flatter panel bolt look...... not healthy to heat galvinized metal though...but you should be ok
Like a pop rivet, huh ? Why not just peen both ends of a tube or rod with a hot nailhead --with a twisting motion to free and finish the "rivet" . . .
Duh -- crossed posts
I use to "glue" plexi with chloroform (yes that is the same stuff used as an anestatic in the movies; to press a white handkerchief in somebodies face).
What it basicly does, is melt the plexi and then the chloroform vapourates into thin air. You need to wear safety glasses!!! and you need a needle-pipet to apply the chloroform....
: B :
email me the poster, I'll put it outside the shop and include it as a handout when I do the shop orientation/training
MEK (methyl ethyl ketone). You can get it at Home Depot. And it won't create haze.
1. be patient
2. ventilate
weld-on 3/4/16
the 16 is more like a glue
the 3/4 is a solvent type that seeps into the pressed pieces..... make sure your edges are cut straight and clean.......
super glue will cause a haze...due to the fumes
another way is by cutting slots into the plexi, place them together (as if they fit together like a puzzle (vertical into a horizontal)), and then you can melt and bend the 'legs' on each plexi so that they are stable.
lasers
methly chloride...it will melt the plastic together....permanent bond
oops typo.
methyl chloride. check a plastics/fibreglass shop
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