Need help on DIY Acrylic Bender

[RtxElite]

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:

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.

 

[KMoffett]

M1. That transformer is too small. You will need 10 to 20 VAC at about 7A to heat a 3 foot, 20Ga wire to 800°F

Q1. No! No! No!
Q2. No. You would need to take 220VAC down to ~20VAC. A resistor that would drop that voltage at the current needed to heat the wire would be huge...and expensive..and not adjustable.
Q3. Nichrome wire changes length as it heats. Coiled wire would be worse. That's why he used the spring wire with straight wire.

Ken

 

[RtxElite]

Oh I see. But a friend of mine made his own acrylic bender without any transformer/power supply too. But he used a heat tube instead of using a nichrome wire. He said he used an 800W Heat tube and plugged it in directly to an AVR and unplugged it when it was hot enough to bend an acrylic. I know that his acrylic bender isn't the safest way to make one but I think that's the cheaper alternative.

Yes I do know that nichrome wire changes length as it heats just as seen in the video. Thanks for the reminder.

I guess I don't have any choice but to follow my friend's acrylic bender. Should I use a nichrome wire(straight wire) or buy an 800-watt heat tube just like my friend did?

Can I use a power supply used in a PC to control the voltage or heat being supplied to the acrylic bender? Coz maybe I can find some spare PC power supplies in my storage. I also have a defective cheap soldering iron maybe I can use some parts of it.

 

[KMoffett]

The heat tube was probably designed to run directly of the power line (220VAC). You can't do that with the coiled nichrome, even if it was designed to run off 220V. It needs to be suspended on ceramic spacers. The spacers would cause cool spots along it's length.

A PC power supply might provide enough power, but you cant vary the output to get the right temperature for bending.

Ken

Ken

 

[RtxElite]

I got another question. Well I have this cheap soldering iron that I got a year ago which is now defective. So I opened it up and I found a nichrome wire. So I was wondering on how can this soldering iron have a fixed temperature or wattage without any resistor or transformer just like you said and be plugged in directly? Maybe I can apply this method into my acrylic bender. That soldering iron's specs is 40W. 220/240V

 

[KMoffett]

It has much finer wire that the bender. It has higher resistance, cannot pass as much current at line voltage levels, and therefore does not get as hot. It actually doesn't hold a constant temperature. I don't think that it would get hot enough for a bender. But, you could try it and see.

Ken

 

[RtxElite]

I found out that there are two layers of wires wrapped around a heat insulator in every layer. After I removed the first wire, I found another wire but it's much thinner than the first one. Both wires are connected to each other.



Which of the two wires produces heat?

I'm really confused. I'm gonna have to study electronics if I have free time next semester.

 

[davenn]

Which of the two wires produces heat?

cant tell ... the pic is just a total blur try again

Dave

 

[RtxElite]

Sorry Dave. My camera is crappy and the wire is too thin like a strand of hair. I'll provide another photo.

This is the first layer. See that wire? That wire is connected to the second wire in the second layer. The wire in the first layer is thicker than the 2nd one.



The 1st layer/wire has been removed. This is the 2nd layer. That curly string is the 2nd wire. It's too thin.