Bending acrylic sheets to perfect tube methods? Suggestions needed

takaaaa · Sep 15, 2016

Greetings, so I need to bend a sheet of thin acrylic into a large tube. It's pretty thin .090" and was told that it could be bent with boiling water which sounds better for full even heating. But the problem is that I don't have the exact shape I need to bend it (I don't have a cylinder that's 13" diameter.
So how would you approach this if you didn't have something of desired shape and size to bend it to?

One theory I have is to measure maybe twice the length I'll need and roll it up twice and hold it with tape, then heat it slowly.

Another thing I could think of is possibly not even heating it up. Just roll it up, over lapping. Since it's thin, I can glue and sand or fill it down to where it's almoat unnotoceable.

What do you guys think?

Pro Mod · Sep 15, 2016

Without a former to work with, just gluing it together is much the safest way to achieve the cylinder.

nathancarter · Sep 15, 2016

Build a form out of cardboard discs that you cut yourself. That's kinda what I did when I needed to make a big cylinder out of Sintra, I used the discs and rings that would be later inserted into the cylinder, taped them together with foam spacers, and formed my cylinder around that.

Here's my stack of three which was all I had, if you need a longer cylinder you'll need a taller stack.

Forming a cylinder on the outside of the rings (my strip was too short to make a complete cylinder, because I am dumb and didn't measure right)

Forming a cylinder on the inside of the rings, I intentionally made the piece too long so it had some overlap, then after heat-forming I cut down the overlap to make a nice clean butt join.

xl97 · Sep 15, 2016

does the acrylic sheet even bend? I would have thought it would break at a certain point.

IMHO.. the best way is get a 13" OD tube.. or even 13" 'disks and use that for the best results. (maybe with the help of a hot air gun?)

I have bend some lexan before... (free form).. and would have turned out MUCH better if I had a guide or form to 'bend against'

nathancarter · Sep 15, 2016

xl97 said:
does the acrylic sheet even bend? I would have thought it would break at a certain point.

I think it'll snap if OP tries to bend it too much without heat.

VioletSun · Sep 15, 2016

I'd suggest making the tube from four sections so long as you don't have to have it in one piece. Making a jig so you can have the acrylic fixed at 90 degrees and then heating it around a former to make a quarter of the cylinder at a time. I tried heat bending acrylic when I was at school and I had to use an oven they had in the machine shop to get it to even wilt (this was about 5mm thick sheet though). I'd also suggest using styrene rather than acrylic if you can as its way easier to bend with heat.

Abelugo · Sep 15, 2016

You need Clear PETG plastic, acylic will not bend or vacuum form more than a slight bend. It is available in different thickness's

nathancarter · Sep 15, 2016

Abelugo said:
You need Clear PETG plastic, acylic will not bend or vacuum form more than a slight bend. It is available in different thickness's

Acrylic won't stretch much, so it's difficult to do compound curves or vacforming. However, it will bend just fine to do simple curves such as cylinders.

I used OPTIX acrylic sheet from the local hardware store to make this tube on a wizard staff, using a cheap heat gun and forming it around a dowel. Masked off some runes with blue tape, gave it a paint job, peeled off the tape, then dropped some lights in to make glowing runes on a staff.

This is the same stuff, flame shapes cut with a jigsaw (lost about 1/3 of them to breakage), dyed with iDye synthetics dye from Joann, formed to the curvy flame shapes with a cheap heat gun, glued together with a LED light in the middle.

Abelugo · Sep 15, 2016

but the smell and fumes!!! the horror!! naw I just found PETG is easier to work with. Good luck

takaaaa · Sep 16, 2016

nathancarter said:
Build a form out of cardboard discs that you cut yourself. That's kinda what I did when I needed to make a big cylinder out of Sintra, I used the discs and rings that would be later inserted into the cylinder, taped them together with foam spacers, and formed my cylinder around that.

Here's my stack of three which was all I had, if you need a longer cylinder you'll need a taller stack.
http://i229.photobucket.com/albums/...g/th_98ACFD0C-D0FB-4AD7-91F3-97D250B7D1D7.jpg

Forming a cylinder on the outside of the rings (my strip was too short to make a complete cylinder, because I am dumb and didn't measure right)
http://i229.photobucket.com/albums/...g/th_28D2685D-250D-4F54-AEE3-6057AE4487D1.jpg

Forming a cylinder on the inside of the rings, I intentionally made the piece too long so it had some overlap, then after heat-forming I cut down the overlap to make a nice clean butt join.
http://i229.photobucket.com/albums/...g/th_23B381C9-2330-4B27-8583-E230E14EAEA1.jpg

Ahhh thats very smart! I think I will do this but possibly with 1" wood (have lots around). Thanks for all the photos!

You need Clear PETG plastic, acylic will not bend or vacuum form more than a slight bend. It is available in different thickness's

Ok PETG it is, is it easier to heat than polycarb? only worked with acrylic and polycarb before

Bending acrylic sheets to perfect tube methods? Suggestions needed

takaaaa

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Pro Mod

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nathancarter

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xl97

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VioletSun

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takaaaa

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