When one of your kids ask, "Hey Dad, can you make a Legend of Zelda birthday cake?", the answer is always "Yes", then you figure out a way to do it.
3/4" x 7" PVC pipe
(1) 3/4" PVC cap
Acrylic solvent cement
Spray paint (gold, silver and blue)
Scrap plywood, particle board, MDF, etc.
Masking or painter's tape
(3) boxes cake mix
water, oil & eggs (per cake mix directions)
(3) or (4) containers of vanilla icing
black food coloring
Tools needed (all available at TechShop):
Miter saw (optional)
Vice grips or pliers
Bench vice (optional)
Hot glue gun
spatula (for icing)
Step 1: Design of the Master Sword
Because the sword was to be inserted in the cake, an all plastic construction was the best way to go. 3/4" PVC was a good choice for the handle, so that is what set the overall scale of the sword. Using CAD (Autodesk Inventor is available to all TechShop members), I started with the dimensions of 3/4" PVC pipe (1.050" OD x 0.824" ID) and just 'eyeballed' the rest of the shapes and dimensions.
Not knowing the size of the stone cake portion yet, I set the length of the blade as long as would fit in the laser cutter. You may download our .DXF file here: http://www.lime3D.net/instructables/zelda.zip
Cut the pieces on the laser from 1/8" acrylic using the recommended settings.
Tip: Whenever making something from acrylic, and plan on painting it, use clear acrylic. This doesn't make any difference with the painting, but you will have more flexibility to use the scraps for other projects.
Step 2: Constructing the blade and guard
Bevel the edges of the triangular 'jewel' pieces on the sander. Holding the pieces with a pair of vice grips will make the job much easier and safer.
Using acrylic solvent cement, stack-up and glue the blade and guard pieces together. DO NOT GLUE THE 'JEWEL' PIECES YET. You can hold the pieces together with a few pieces of masking tape. The solvent cement works by chemically melting the pieces together, so to hold the pieces flat and in the proper position while the plastic cures, you can clamp them between two scraps of wood in a vice (or C-clamps), and leave it over-night.
After the pieces have cured, you can clean up the edges with a flat file or sandpaper.
Step 3: Constructing the handle
The grooves on the handle can be created on the bandsaw, but first you need to make a fixture. Using the bandsaw, cut a slot in one side of a scrape piece of plywood or MDF. The depth of the slot needs to be at least the depth of the blade. After the slot is cut, turn the board around, and secure it to the table with clamps. This will be a backstop for cutting the grooves. To set the depth of the grooves, position the board so that the saw blade will cut no more than 50% of the PVC wall thickness.
Line up the marks on the PVC with the band saw blade, and while the saw is running, push the PVC up against the stop. Slowly rotate the PVC, so that the blade cuts all the way around. Repeat this for all of the marks. If you want, you can also widen the groves using the same technique.
You can also use the bandsaw to create a slot in the end of the handle for the blade portion to fit into. You can also use a flat file to create the slot. (We used both.)
Spray paint is easily scraped off PVC, so you need to rough it up (just like the acrylic) to give the paint something to 'bite'. The sander makes short work of this, and if you rotate the PVC when sanding, it will create a nice texture. If you don't like the texture, or if it is too rough for your preference, you can follow it up with sandpaper.
The same is true for the PVC cap. By using the sander, you can also get rid of any text or other features that are left over from the molding process.
Attach the cap to the handle with hot glue. Add more hot glue to the inside of the other end of the handle, and insert the blade, all the way in, setting the edges of the blade in the slots.
Step 4: Painting
After it has dried, mask the blade and paint the handle/guard section.
Tip: Plastic trash bags are a cheap, quick and easy way of masking large areas.
After all of the pieces have dried, attach the jewel pieces with hot glue.
Step 5: Making the cake
Bake three cakes in 9" x 13" pans. When cooled, remove the cakes from their pans and stack them. Using a bread knife cut the long ends off on an angle with a bread knife.
For this cake, you will notice that we substituted the middle layer of cake with 'Superman' ice cream. (It is the birthday boy's favorite.)
Add a small amount of black food coloring (again, to simulate stone) to vanilla icing, and frost the cake. (Unfortunately, we could not find black food coloring, so we substituted black decorating icing, which made it a little more lavander than grey. Also, the soft, melty ice cream made it extremely difficult to spread the icing, but you get the point.)
Tip: Continually dipping your icing knife in hot water will help you create a smooth surface on the cake.
Take a look at the scale of the cake vs. the sword. If the sword looks a little long, just cut the end of it off with the band saw, or scribe a line with a utility knife, and snap off the end.
Keeping the sword straight up and down, push it into the top of the cake, until it hits the plate or board underneath.
Finally, take your cake to the party, and amaze and delight the guest of honor!
I have been designing products in the automotive, aerospace, medical, defense and consumer products industries for over 30 years. I am an "Inventor for Hire", so if there is something you need designed or built, just send me a message, or stop by http://www.lime3D.net , and maybe we can do business!