In this project-based tutorial, you’ll learn all of the steps needed to make your own Guardian Sword from Zelda: Breath of the Wild. We’ll go through all of the printing, processing, and assembly steps needed for you to create your own replica.
This project was originally done by Adafruit, so check out their tutorial here! Make sure to reference their required parts and tools list so that you can follow along. We’ll be adding a few additional steps to their tutorial which includes part splitting so that this can be printed on smaller machines, and part painting to create a weathered finish.
We printed each of the components for the Guardian Sword on the Formlabs Form 2. Compared to FDM printing, SLA produces a higher quality surface finish, works with a wide variety of different bonding techniques, and takes better to paints. Learn about the main differences between FDM, SLA, and SLS here.
The Formlabs Form 2 has a build volume of 145mm x 145mm x 175mm which isn’t quite large enough for the files that Adafruit created with a 1ft x 1ft build volume in mind. We’ll be splitting and bonding each of the main components to accommodate the smaller build volume.
Meshmixer is a free tool produced by Autodesk that’s well suited for making simple cuts on STL files. To get started, import your file into Meshmixer and select the ‘edit’ menu. From there, select the ‘plane cut’ option.
Select the green manipulator to rotate the plane 90 degrees such that it bisects your components into two halves. Tip: with the green tool selected, drag your cursor to the circle of dashes to iterate by 5 degrees at a time and produce an exact 90 degree angle.
Hit accept to make the cut, and only the object on one side of the plane will remain. Save this half out as an STL, and use the undo button to navigate back to the plane cut dialog. Now reverse the direction of the cut using the large blue arrow, and save out the second half of the file.
Use this technique to segment all parts that are too large for your printers build volume. Check out this tutorial by Formlabs for a deep dive on creating parts larger than your printer’s build volume.
After your parts have been split, it’s time to get started with printing. Regardless of your printing technology, stick to a clear material so that the lights shine through. We’ll be using the Formlabs Form 2, and orienting parts such that the supports are on flat and accessible faces for easy cleanup.
Each of the ‘cover’ components are made from long strips of black plastic, and we opted to laser-cut these instead of printing them. Laser-cutting tends to be a faster process than 3D printing for parts that are relatively thin and flat. If you opt to follow the laser-cutting route, grab the DXF files here!
SLA printed parts have small support nubs that are sanded away after printing. Start with a coarse 100 grit sandpaper to remove the majority of the nubs. From there, use a 200 grit sandpaper to remove any residual marks and smooth out the surface.
A higher grit sandpaper isn’t necessary, as we’ll be painting the parts later on. Double-check your part for any residual marks from support structures, as painting will cause these to become more visible.
Those of us that aren’t gifted with a 1ft x 1ft bed likely had to split each of the components in Meshmixer to make them printable. To bond the split parts together, we’ll be using a mixture of resin welding, superglue, and epoxy.
Resin welding is a process most compatible with SLA printed parts, whereas photopolymer resin is deposited on the seams of a part and then hardened with a UV laser. This has the advantage of high bond strength, homogeneous material properties, and homogeneous surface finish after sanding.
Resin welding will be used on the exterior surfaces of the parts, so start out by using a thin shaft to deposit a small amount of resin on the seam between components. Use a UV laser pen to harden the liquid resin and bond the seam. Tip: start off with a small dots of resin across the seam to secure the part in place. From there, spread resin across the rest of the seam until no gaps remain.
Once the resin has hardened on the exterior surfaces, flip the part and use superglue to secure the seam from the inside. This has the advantage of being faster, and because the interior seam won’t be visible, we don’t need to worry about homogeneous material properties.
Start from the handle, and work your way up each half of the sword using this process. Adafruit has included screw points that will help to add additional strength to your bond.
If you plan on walking around with your sword, it may be a good idea to add additional strength to your bonded parts with an epoxy. We applied a generous amount of XTC 3D overtop the superglue on the interior to add additional strength to the seams.
Once your parts have been bonded, it’s time to clean up the seams on the exterior facing surfaces. For this, we used a rotary tool with a sanding disk as it tends to remove material much more quickly than hand sanding.
After flattening the majority of the seem with a rotary tool, we used 200 grit sandpaper for the final touches. When done correctly, this technique will yield a smooth surface with no indications of having been bonded together.
Wiring the Electronics
With both halves of the sword completed, it’s time to move onto the electronics. The circuit consists of a Trinket M0 board, LiPo Backpack, LiPo Battery, Power Switch, and LED Strip. Refer to Adafruit’s Circuit Diagram below for wiring.
Many of these components can be tricky to wire, and we have a few general tips to make things go smoothly. To solder wires to the board, strip and twist a small section of wire and deposit a small bead of solder onto the header of the board. When you’re ready to attach the wire, melt the solder and press the wire up and through the header.
To wire to the LED strip, start with a small bead of solder on the pads of the LED strip. Cut and twist the appropriate amount of wire, then melt the solder and press the wire down and onto the pad. This can be tricky to get right, and it took us a few tries to create a secure connection.
If you opt to use a power switch, a slight modification needs to be made to the Trinket M0 board. The board is always on by default, so the connection between the two switch headers must be severed to operate properly. Use a sharp x-acto knife to cut across the connection between the two switch headers. If this connection is not fully severed, the board will remain always on regardless of switch position.
With your circuit completed, it’s time to get started with programming your board. The M0 series boards by Adafruit make this process especially easy by eliminating the need to compile and upload firmware through the Arduino IDE.
Refer to Adafruit’s CircuitPython instructions to prepare your board from programming. This involves installing device drivers and copying over a .uf2 file. Once your device has been configured and shows up as CIRCUITPY in the device manager, grab Adafruit’s Guardian Sword Code and save it to the board as main.py. Make sure to copy over the CircuitPython code rather than the Arduino code in this step.
With the file saved, your LED strip should illuminate with distinctly teal and orange sections. Depending on the length of your strip not all of the LEDs will be used, and after unpowering the board cut away any unused LEDs.
From here, secure the electronic boards into your sword using the M2 and M2.5 screws. Power on the LED strip, and align the colors to the appropriate sections along the sword. To secure down the LED strip, we used a generous amount of superglue. Make sure to only glue to the plastic covering of the LED strip, and avoid getting glue onto any of the electronics components.
After you’ve fit and secured all of the electronics, you’re ready to seal the sword. Start by combining the two halves, and fasten them with the M2 x 12mm screws. It’s unlikely that the split between your two halves will be perfectly straight and seamless by default, so we’ll clean this up with a bit of glue or resin.
Use the resin welding technique we discussed earlier or a high viscosity super glue to close the seam between the two halves. Sand down the residual adhesive with a rotary tool or high grit sandpaper to produce a sword that appears as a single printed part.
In Adafruit’s tutorial, the sword was made using a clear material with a slightly opaque surface finish. Here, we’re going for a more aged look which we’ll achieve with a surface that’s painted white and sanded in certain regions.
The only required prep work is to cover the two electronics openings with a bit of painter’s tape. Generally, primers are used as a base coat for additional paints, but here we’ll be using a primer as our final finish.
In a well ventilated area, apply a thin coat of primer to one side of the sword. Don’t worry too much about missed areas, as many thin coats of paint tends to produce a better finish than a few thick coats. For a deeper dive on best painting practices, check out this tutorial.
Once your first coat of paint has dried, apply a second light coat, making sure to hit any uncovered areas. Tip: light up the sword to more easily identify unpainted regions. Once your second coat of paint has dried, flip over the sword and repeat the process on the other side.
After painting, your sword should be completely covered in a thin layer of white paint. From here, we’ll selectively remove the paint to produce a weathered look.
Use a coarse grit sandpaper (100 grit – 200 grit) to remove paint from the regions of your sword that you’d like to highlight. We opted to remove paint from the edges, and applied some scratches to the body of the sword.
This step is most easily done with the sword powered on, as it allows you to see which regions have been exposed in real-time. After sanding and weathering your sword, you may choose to call the project complete, but we opted to apply a final clear coat to protect the white primer layer.
We found that a Matte clear coat produced the best finish, but Satin and Gloss options exist as well. Apply the clear coat in two thin layers much like we did with the white primer from earlier. This adds additional strength to your sword, and protects the white paint from further weathering.
From here, your Guardian Sword is complete! The final result is a sword that looks great unpowered, and even better when illuminated. Thanks to Adafruit for putting together the original tutorial, and let us know how yours turns out in the comments below.