Greetings,

I have watching some YouTube Videos in which people are using NiChrome Wire as a heating element to bend acrylic. I went out and bought a blow dryer from the GoodWill store for 99 cents and pulled the heating element out.

Here are some of my questions:

1. After stretching the coils out the wire is really long. How would one get the correct length?

2. I would like to be able to bend up to 1/4" acrylic maybe up to 24" wide. Will this get hot enough?

3. Could I take two equal lengths of the wire and twist them into one thicker element to produce greater heat output?

4. What would be needed to build a nice solution like having a knob that could reliably change settings based on acrylic thickness?

Cheers,

 

What would be needed to build a nice solution like having a knob that could reliably change settings based on acrylic thickness?

Your best solution would be a controlled heat element. The way to go about that would be likely using a Variac Transformer (Autotransformer) to drive your heating element or similar means like a lamp dimmer. The problem is regardless of what you use it needs to be able to handle the power of the heating element. Your heating element also needs to be isolated. Blow driers and similar generally use a nichrome wire coiled to have a specific resistance and to give a given amount of heat for an applied mains supply voltage. Mains voltage is a function of your location. It's not as simple as just plugging in your nichrome strip to a power source. There is both a shock and burn hazard present.

Bending acrylic is not that difficult but to make a decent benser people need to know your mains voltage? What was the power rating of the drier you took apart? What gauge is the wire you salvaged?

Ron

 

All good points and questions.

So I have a bench top power supply that could use if needed. But I would like to develop something a little more user intuitive for my maker-space.

I am in the US and have 120V at my disposal.

The gauge of the wire - .45mm (measured with calipers)

Trying to find my multimeter (just moved) so I can measure an inch of it to get R/inch.

 

OK, what you need is a fairly accurate resistance of the wire gauge. Knowing that and the mains voltage will give a good start, Once we know about what the power will be then we can worry about controlling the heat.

Ron

 

They used to do this, heating the Plexiglas, with "heat lamp type bulbs". Much more efficient than nichrome. A single row of nichrome really doesn't give heat over a very large surface. Like this type of bulb - https://www.bulbamerica.com/collections/heat-bulbs

Found a copy of a manual for plexiglas bending -

 

The "commercial" versions use wire. Boy they sure aren't cheap.

https://www.ebay.com/itm/110V-48inc...rentrq:f560cdb51670ab116b1e8304fff3e431|iid:1

For some reason they also use water. Maybe once you get it bent, you want to cool immediately?

 

The "commercial" versions use wire. Boy they sure aren't cheap.

They may now, but like I said, "they used to use heat lamps". One of my brothers worked at a place the did vacuum forming of plexiglas, and they had a box enclosing rows of heat lamps. The wire coils would only be good to make a single sharp bend, but not do other forming.

 

I've done some of this myself .... you have a bench top supply? variable ?? up to about 30V ?? ....

Perfect , that's all you need ....

you want to bend up to 24" so cut a piece of wire 30" long , connect to your supply and crank up the volts to get the wire at the right temperature, you shouldn't need more than 30V , but if 30V doesn't get the wire hot enough , double or triple up twisting strands of wire together.
..you really need spring tension on the wire , find a small spring and keep the wire under tension as he heats it will lengthen , the spring keeps it taught , bang two nails in you work top , anchoring the wire , with one end of the spring on one nail the other end of spring to wire , other end of wire to nail.
Keep temp fairly low and allow minutes to soften the acrylic.