G'day! I made a hot wire heat bender. You might need one of these for creating bends in acrylic. At Core Electronics, we bend a fair amount of acrylic and until now we've gotten away with using a hot air rework station. We decided it was time to get a real tool for the job, so this hot wire bender works really simply. You just bring your acrylic up to the hot wire channel that runs down the middle and after the acrylic reaches temperature, you can just bend that table back to create your bend at any angle that you need.

This is really simple. It comes down to just a piece of nichrome or nickel chrome wire in this aluminium channel, being secured with a screw at each end and a spring to keep the tension on the wire. Other than that, you've just got two plates of plywood connected by a hinge so you can create that bending action.

Let's have a look at the plans. This project is really simple and gratifying. You can knock it over in an hour really. I made it from a single piece of 600 by 897 ply and actually the hardware store even did the cuts for me, so I didn't have to do any real cutting operations. I just had them cut the single piece of ply into two identical 250 millimeter wide pieces and then once I had those, just trimming a bit off the ends to make them 500 millimetres wide off the original 600.

So this hatching here, this is all the waste material for the project. It's quite material efficient. Now, as if by serendipity, the same hardware store also stocks 12 millimeter square aluminium molding, so that's just a like a c section of aluminium channel. So 12 millimeter molding, 12 millimeter ply, you get this really beautiful flat working surface.

As far as assembly goes, all you have to do is screw down this b plate against the edge of the a plate.

Then, screw down the aluminium channel nice and firm against that first B plate. Use the hinges to join the first B plate to the second B plate. This one is fixed and this is the one that will do the folding action. Referring to the section drawing, you can see the main large A plate with the fixed B plate. The hinge and the hinging B plate in blue is the aluminium channel and right in the middle in red is the hot nichrome wire.

To secure that nichrome wire, one end is tied around a screw that's driven into the A-plate at the end of the channel. On the other end is another screw that connects to the wire by a tension spring. As this nichrome wire heats up and cools, it expands and contracts quite a lot, so it's necessary to have this spring to power the bender.

All you need to do is connect a DC power supply to either end of the wire. Make sure you don't connect it downstream of the spring, make sure the connection is on the hot wire and to the spring. If the spring gets hot, it may anneal and kind of relax into that new length. Use a lab DC power supply running at about 25 volts and 3 amps over this run of wire. That works out to be about 75 watts or 70 watts. If you have a power supply that is not 25 volts 3 amps for this 52 millimeter run, you can take a fixed supply, say 12 volts, and adjust the nichrome wire to suit that power spec. Maybe you have to double it up on itself to make a lower resistance wire that will take a higher current.

From the top, you can see the screw with the tension spring.

That's that spring you can just pick up at a hardware store. That's what that looks like and on the end we've just tied off the nichrome wire and on the other end is just a thick spring. There you have it! Overall, I'm really happy with how this performs. You only have to put the acrylic on for a moment before it's hot enough to then bend up.

I think I could probably drive this a bit harder. It could be a bit faster in hitting the acrylic and that might just be a case of paralleling the channels of my power supply to go above that three amp limit. If I were to do this again, I'd look into using maybe instead of this structural ply, maybe consider using like form ply or melamine something with a really nice clean surface. This is fine, but it leaves behind quite a lot of dust on the acrylic just the dust that comes out of the ply. So if you have something much cleaner like a form ply or melamine finish like a countertop material, that might be really nice and also maybe prevent scratching on the acrylic as well.

Other things you could do, you could put in a stopper like a right angle guide to make alignment very easy to get nice square bends. You could add like an angled block or some kind of adjustable guide so you get repeatable bend angles. This really is a blank canvas.

If you have any uncertainties, please just let us know in the comments section below. I realized I got into the weeds a bit with the power ratings and the voltaging current through nichrome, so yeah any uncertainties let us know. Until next time, thanks for watching!