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  1. #1
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    Need help on DIY Acrylic Bender

    Hey guys! I don't know much about electronics but I really need help in making an acrylic bender for case modding coz I can't afford buying pre-manufactured ones.

    This is the guide that I've decided to follow:
    http://www.youtube.com/watch?v=wVEf7PfuKxo

    I'm planning to plug the acrylic bender directly to an AVR without the use of a power supply/transformer just to make it simpler. But I do have a transformer which I bought for a radio. Maybe I can use it.

    Materials I have:
    1.)Tamagawa Transformer - 500mA, 6V x 2

    2.)Nichrome Wire(Spring Type) - 600 Watt - Wire is thin just like the one you see in a pen.

    3.) Black and Red Wire

    4.) Alligator Clips

    5.) Wire for outlet

    6.)AVR



    Questions:

    1.) Can I make the acrylic bender work by plugging it directly to an AVR/Outlet without any transformer/power supply?

    2.)Without a transformer, can I control the amount of voltage being sent to the nichrome wire just by using alligator clips or by some resistor or is there any simpler way possible?

    3.) As I stated the nichrome wire is spring type and I'm afraid the nichrome wire might bend and touch the wood or aluminum channel. Can I cut/shorten the nichrome wire and make it straight just like in the video? Or should I buy another type of nichrome wire(the one in a roll)?


    I'm from the Philippines and we're using 220v. Please if you have any suggestions I'm willing to listen. I just need to make an acrylic bender the cheapest and easiest way possible. Thanks in advance.

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  2. #2
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    Re: Need help on DIY Acrylic Bender

    I've bent plastic using a piece of brake line tubing and a
    heat gun, never tried NiCr as a support. That tends to get
    soft and elongate when you get it real hot, but presumably
    you will control to a lower heat than that. Still you may
    need a tensioner for the NiCr.

    You might also consider a plain steel strip, which would
    eat more power but be more properly rigid if edge-on.

    I don't think 500mA@6V is going to be enough heat.
    If you ain't skeered of a little risk, a lamp dimmer and
    a piece of steel wire / strip might be more in the range
    of useful heat-throw. You probably want about an ohm
    of cold resistance I'd guess. Stainless steel is more
    resistive than mild, generally, and might be a good
    choice.



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  3. #3
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    Re: Need help on DIY Acrylic Bender

    Yeah someone told me that 500mA @ 6V isn't enough and I'm gonna need more than that. Thanks for the suggestion, but that's a bit complicated for me. If only I knew more about electronics.

    I have this soldering iron which is now defective considering it was very cheap. I opened it up and found a nichrome wire(please correct me if it isn't). So I was wondering on how did this soldering iron(without any resistor or transformer) have a fixed wattage or temperature which I think is also enough to heat up an acrylic and bend it? So I was thinking maybe I can apply the same method to an acrylic bender.



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  4. #4
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    Re: Need help on DIY Acrylic Bender

    1, No it will be extremely dangerous
    2, see 1
    3, Straighten a section out for your need and fasten one end down to the board. Beyond the other edge of the board, let the remaining wire fall to the ground (or cut it off when you are certain of its length) and feed it over a smooth metal edge like a piece of tubing. Now attach a weight to the loose vertical piece of wire so the weight is hanging off the wire. Once its set up with the right weight, it should pull the length of wire straight which should move freely over the tube.
    4. The chap on the video said 10 to 12 V, but not at what current. I would think it was at least 3 A, so i think your transformer is too small, have you access to a car battery? = They are good foor a lot of current providing you charge it up or put it back in the car before its flat.
    Frank



  5. #5
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    Re: Need help on DIY Acrylic Bender

    I see. How about that soldering iron that I posted? Can I use it? Please see my 2nd post. I don't have access to a car battery, but I do have a PC Power Supply. The one you use to power up your motherboard and the other components.



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  6. #6
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    Re: Need help on DIY Acrylic Bender

    That iron probably wants 120V to get full tolerable
    power (i.e. without burning itself up). But that is all
    tied up with the rest of the thermal path. Putting
    12V across it will net you something more than 1/100
    the power (because resistance goes up w/ temp, so
    somewhat self regulating.

    You might take the mechanical suggestion about
    the tensioning weight, and go further by making the
    weight, be a bolt/washer/nut clamp onto the wire
    that also is one end of the power feed - position
    the feed-weight along the wire length such that you
    get the desired power / temperature.

    Now, you have to consider whether this hot wire
    will nicely bend, or simply melt into, the workpiece.
    A concentrated heat source is not your friend really.
    It can easily fet away from you. A larger diameter
    rod (like, say, stainless welding rod, available in
    1/32" up to 1/4") might be more the ticket, and
    develop more power in the heater than NiCr sized
    for a higher voltage. Particularly if your workpiece
    is larger than the length of NiCr you've got, or the
    length that develops useful heat at 12V.

    Car battery, fat cables, and bolt-clamped welding
    rods of varying diameter is an easy experiment to
    try. Maybe use a tension spring since the rod can't
    just be draped over something and weighted.

    But don't discount other methods such as an IR
    lamp or heat gun, and a passive forming jig. These
    can be a lot more controllable. You can get a heat
    gun that's more than adequate for about ten bucks
    at Harbor Freight.

    PC power supplies can throw decent current, not as
    much as a car battery but at least 100-150W out the
    5V and 12V outputs. This might play well with the
    thinner welding rods (I like about 60A in a 3/32" steel
    rod for arc welding, you'd like to be maybe 1/10 or
    less I expect, so not-insane). Your length of rod sets
    the heat, may as well play around some and see.



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