Introduction: Hot Wire Ice Cutter
Have you ever wanted to sculpt something out of ice? Well here is an easy way to do it that doesn't require a chainsaw. In this project, I am going to show you how to make a "hot wire ice cutter."
The design for this project is very similar to other types of hot wire cutters. Electricity is sent through a piece of Nichrome wire. This heats the wire above the melting temperature of the material that you are working with. The wire can then be used to "cut" the material by melting it along a narrow line.
Because ice sculptures are often larger and more difficult to handle, I designed my cutter to be handheld rather than stationary on a table. I based my design largely on the "Hot Wire Foam Cutter" by Instructables user FlyWoodKB. I made a few modifications to make it safer and easier to use with ice.
Step 1: Watch the Video
Here is a video walkthrough of the project.
Step 2: Materials
Here are the materials and tools that you will need to complete this project.
Nichrome Wire (available on Amazon)
3 Feet of 1x2 Lumber (actual dimensions: 3/4" x 1 1/2")
4 x 1/4" Bolts, 2" long
10 x 1/4" Nuts
8 x 1/4" Washers
High Current DC Power Supply (such as a laptop power supply)
1/4" Drill Bit
Step 3: Cut the Lumber
The first thing that you need to do is cut the piece of 1 x 2 lumber into three pieces that are each about one foot long. Try to keep them the same length.
Step 4: Mark and Drill the Mounting Holes
Now we need to drill holes in each piece of lumber so that they can be bolted together.
First I measured and marked the center line of each piece. This helps to ensure that the holes will line up.
Then on one piece, I made a marks that were 3/4" from each end. This will be the cross piece.
On the other two pieces, I made one mark that was 3/4" from the left end and a second mark that was 6 3/4" from the left end (6" from the first mark). These will be the side pieces.
Drill a 1/4" hole at each of these six locations.
Step 5: Attach the Bolts and Assemble the Frame
Now it is time to assemble the frame. Start by attaching the three wood pieces together. Put washers on two of the bolts and insert them through the holes on the two sides of the cross piece. Then attach the two side boards by fitting these bolts through the holes located 6 3/4" from the end of the side boards. Secure them in place with washer and nut.
Next attach the wire mounting bolts. First screw two nuts onto each of the remaining two bolts. Leave a gap between the first nut and the head of the bolt. This is where the nichrome wire will be attached. Also leave a small gap between the two nuts to make it easier to adjust the spacing later. Then add a washer and insert the bolts through the holes on the ends of the two side pieces. Add a washer and nut to the other side to secure the bolt in place. Lastly add one more nut onto the end of each bolt. Leave a small gap between the last two nuts. This is where the power supply wires will be attached.
Step 6: Select a Power Supply
Here are some things to consider when selecting a power supply. I highly recommend using a DC power supply to reduce the risk of shock. I also recommend using a power supply whose output wires can easily be separated. For instance zip-cord style power cords have the wires separated and each one has its own insulating jacket. They are connected together by a thin strip of insulation that can be easily pulled apart without exposing either wire. This lets you easily connect power to the two sides of the cutting wire without a lot of exposed wire running around.
Determining how hot a power supply can make a wire is a little complicated. You can't just look at the wattage rating. You need to calculate the watts per foot that the power supply will output as part of the system. So you need to do a little math.
Check the label on the power supply to see what its rated output is (volts and amps). This is the output that the power supply is designed to have. So in most cases it is best to duplicate this with the load of the hot wire cutter.
First calculate the wattage rating of the power supply by multiplying the output current (in amps) by the output voltage (example: 12V x 2.0A = 24 Watts). Next divide the output voltage by the output current (in amp) to get the designed resistive load (example: 12V / 2.0A = 6 ohms). Now find out how long of a wire you need to make this resistance. For instance, a nichrome wire with a resistance of 10.6 ohms per foot will need to be 0.57 feet (6.8 inches) long to have a resistance of 6 ohms (6 ohms / 10.6 ohms/foot = 0.57 feet). Lastly divide the wattage rating of the power supply by the length of the wire to find how many watts per foot will heat the wire (example: 24 Watts / 0.57 feet = 42.1 Watts/Foot).
This "watts per foot" rating is an indication of how hot the wire will get. You can't draw an exact temperature from this because that will depend on how and where you are working. The wire will be cooled at a rate that is dependent on the temperature of your working environment. But it gives you a good way to compare the relative output of different power supplies.
Step 7: Attach the Nichrome Wire to the Frame
Now we need to attach the nichrome wire. In the last step we calculated how long the wire would need to be based on the power supply that you are using. Take this length and add two inches to it. This will give you a little extra wire to make loops on both sides.
Cut off this length of wire. Make a loop on each end and twist the loop so that the two sections of the wire are wrapped tightly together and make a strong connection. I recommend using a battery or a pencil to twist the wire while you hold the other end with a pair of pliers.
Fit the two loops over the heads of the two bolts. You can twist the adjacent nut onto it to help hold it in place. But do not tighten it too much or you can break the wire.
Step 8: Wrap a Rubber Band Around the Handles of the Frame
It is important that the wires always be held tight. This helps to prevent accidental short circuits and shock. It also helps to prevent accidental burns. To do this, you need to constantly be applying pressure to the handles. The best way to do this is with a rubber band.
Wrap a rubber band around the back end of the handles. To help keep it in place, you can cut a small notch in the wood where the rubber band can sit.
Step 9: Connect the Power Supply to the Wire Cutter
Next we need to connect the output wires of the power supply to the other end of the bolts on each side of the cutting wire. Start by cutting off the DC power connector from the end of the power supply's output cord. Then separate the two wires for the last foot of the output cord. Strip about one inch of insulation off of the end of each wire.
Wrap the exposed wire around the two bolts and tighten the nuts onto the wire to secure them in place.
To help keep the wires from moving around while in use, I recommend taping the power wires to the boards. Just hold the wire onto the surface of the board and wrap a piece of masking tape around the whole board. Do this in several locations.
Step 10: Use the Hot Wire Ice Cutter to Sculpt Ice
Once everything is assembled, you are ready to start working. Get a large chunk of ice or a stack or smaller pieces of ice and set them up on a dish in the middle of your work space. You will drip a lot of water so make sure that you can contain it.
Now you can plug in the power supply. The wire will immediately start to heat up.
BE VERY CAREFUL!!! This wire extremely hot and will burn on contact. It can catch objects on fire. It can easily cause third degree burns. Exerciser when using the hot wire cutter and always turn it off/unplug it whenever you are not using it.
Hold the frame with both hands and slowly move it through the ice. You may need to move the wire back and forth a few times to prevent the ice from refreezing after the wire passes through. Slowly cut and remove chunks of ice. Keep in mind that the ice will be melting as you are working. You may need to periodically put the block in your freezer to let it refreeze before resuming work.
You can use the hot wire ice cutter to shape snow and ice outdoors as well. But keep in mind that the outside temperature will affect how well the wire can cut. If it is freezing outside, the wire will lose lot of heat to the surrounding air and it won't be able to cut as fast. So you will need to work much more slowly.
Be creative and have fun. But above all be safe.