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Anyone tried to bend clear plastic sheet ? — Parallax Forums

Anyone tried to bend clear plastic sheet ?

BritannicusBritannicus Posts: 98
edited 2014-06-04 00:47 in Robotics
I've got a sheet of 3mm thick perspex - I'd like to use it for creating interesting housings etc.
Has anyone tried shaping perspex sheet into curves / rightangles - I''m figuring some kind of heat treament to soften it, but figure I could get myself really snarled up with burning plastic an dmelted goo - before I do, has anyone got any advice ?

Comments

  • LeonLeon Posts: 7,620
    edited 2011-05-11 04:54
    Heat is used, it's a thermoplastic. I've heard of people doing it with a gas torch, but it's easy to overheat and burn it; I tried it when I was a kid. I vaguely remember heated sand being a good way to mould it without the proper equipment, which is carefully controlled electric heating. Boiling water works well, also.

    Perspex is the UK trade name for acrylic sheet, for the foreigners! Lucite in the USA.
  • schillschill Posts: 741
    edited 2011-05-11 05:17
    Probably more common to call it Plexiglass in the US (a brand name like Perspex and Lucite). When avoiding brand names, I've usually seen it called acrylic in the US (as Leon mentioned).
  • LeonLeon Posts: 7,620
    edited 2011-05-11 05:18
    I'd forgotten Plexiglass, it does seem to be more common these days.

    When I took an engineering design course 50 years ago I learned the proper name for it - something like poly-methyl-methacrylate. :)
  • ZootZoot Posts: 2,227
    edited 2011-05-11 06:10
    Here's a great instructable for doing just what you want: http://www.instructables.com/id/Poor-man-s-200-dollar-plastic-heat-strip-for-penni/
  • prof_brainoprof_braino Posts: 4,313
    edited 2011-05-11 07:25
    Zoot wrote: »
    Here's a great instructable for doing just what you want: http://www.instructables.com/id/Poor-man-s-200-dollar-plastic-heat-strip-for-penni/

    Brilliant! I have melting plastic in my future!
  • Phil Pilgrim (PhiPi)Phil Pilgrim (PhiPi) Posts: 23,514
    edited 2011-05-11 08:08
    There are also tools ready-made for bending acrylic, viz:

    -Phil
  • RobotWorkshopRobotWorkshop Posts: 2,307
    edited 2011-05-11 08:24
    I have a 36" EMX strip heater. It works great and I just used it to make some custom parts for one of my latest robot project. It is just like the one listed at this site:

    http://www.usplastic.com/catalog/item.aspx?itemid=23104&catid=698
  • GordonMcCombGordonMcComb Posts: 3,366
    edited 2011-05-11 09:05
    The self-contained units are good for production work, but for one-offs you can use a strip roll, like the ones at the top of this page:

    http://www.craftics.net/ShowItems.aspx?Category=86

    -- Gordon
  • Beau SchwabeBeau Schwabe Posts: 6,568
    edited 2011-05-11 10:00
    Word of caution: Anyone attempting this with a heat gun, should make sure that there heat gun is labelled "Flameless". In other words an induction motor rather than a brushed motor. It's rare, but I have seen on more than one occasion the effects of flash-over. Some of the fumes released as plastic is heated can be flammable. A heating element usually isn't enough to ignite the fumes, but a spark from the armature of a brushed motor can.
  • Phil Pilgrim (PhiPi)Phil Pilgrim (PhiPi) Posts: 23,514
    edited 2011-05-11 10:13
    BTW, I just tried bending some thin Plexi using my bag sealer. But the timer doesn't keep the heating element on long enough to soften even 1/16" plastic.

    -Phil
  • NikosGNikosG Posts: 705
    edited 2011-05-11 13:27
    Hi,

    Plexiglass is my favorite material for robotics creation and I have work alot with it. However I have never tried to bend it. But some times as I cut the plexiglass I realize that this material has different reaction acordind the type of the plexiglass. You can build a variety of shapes using smaller pieces of plexiglass and metal brackets to connect them. I think It is easier to bend the metal brackets in order to create your shape.
  • CrazyrabbitCrazyrabbit Posts: 116
    edited 2011-05-11 18:34
    In grade school shop we use to use an oven around 200 F.We made wood forms and pressed in in while hot. Be careful and don't forget the gloves. You have to work fast. Nicos is right. Most my robots are plastic lexan/erector set creations.
  • kwinnkwinn Posts: 8,697
    edited 2011-05-11 21:32
    You can also "solvent weld" separate pieces together to make parts, enclosures, and other items. Very strong and quick setting joints using a syringe and solvent.
  • Duane DegnDuane Degn Posts: 10,588
    edited 2011-05-11 23:10
    I saw a TV show where they did something similar to what Crazyrabbit described.

    They were trying to make a acrylic dome so the had a sheet of acrylic sandwiched between two pieces of plywood with a large central cut out. The put the plywood and acrylic in an oven and then pressed the acrylic over a form. It took them several tries, but it looked pretty cool once it worked.

    Another TV program (I really don't watch a lot of TV) showed the making of and acrylic submarine. That was amazing. The acrylic sub could safely dive deeper than the WWII subs. They used cast acrylic for the sub. The had to bake the huge pieces in a large oven to get them to cure correctly.
  • Beau SchwabeBeau Schwabe Posts: 6,568
    edited 2011-05-12 08:19
    You can also vacuum form many different plastics with just a little bit of negative pressure. Although I haven't done this with Plexi-glass, the preferred plastic of choice in prosthetics is polypropylene or DI-Clear. Both of which are thermoplastic polymers. In prosthetics, we used modified pizza ovens to reach 300 to 400 Deg F, and a Venturi style vacuum pump from the compressed air we had on-hand in the shop to vacuum form our plastic over a positive mould.
  • kwinnkwinn Posts: 8,697
    edited 2011-05-13 11:06
    A shop vac also works well. Thin sheets of PVC can also be formed this way.
  • jhon505jhon505 Posts: 1
    edited 2014-06-04 00:47
    Many items and heating elements available in the market like solvent weld and many other. You can get them very easily from the market and the internet and then you can easily clear the plastic sheet. Once time i use this equipment its really very helpful for me...........
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