Introduction: (Relatively) Indestructable Concrete Death Stars!

Hey fellow instructablers! For my first instructable, I wanted to provide the instructable community with its own version of instructions on how to make the iconic Death Star out of (relatively) indestructible concrete. These amazing little sculptures take little over an hour to be solid enough to handle (and a few more hours to be completely cured) and require only the mixing and pouring of cement into little silicone moulds you can obtain from a variety of online websites (My go-to choice was Amazon). The moulds are actually meant for ice cubes, but when you substitute the water for cement, the end result is a surprisingly detailed replica of the Death Star that is durable enough to guarantee years of visual satisfaction.

I have to give credit for this incredible recipe to the authors at HomeMade Modern and at the one and only at

I started this project to fulfill a demand for Star Wars memorabilia for an upcoming event for my Fraternity, Alpha Phi Omega, Alpha Delta Chapter, (San Diego State University). The event, named Fall Fellowship, was Star Wars themed (obviously) and included activities and dinner. After a little research with my partner, we found the websites listed above and found the perfect, over-the-top gift. The different shades of concrete and the concrete's immense strength seemed all too fitting for creating the Death Star. After many failed attempts at building this world destroyer out of concrete (I made at least 20 before I got the technique down perfectly) I finally got into my grove and cranked out sixty (60) picture perfect little Star Wars souvenirs to be included in the center-pieces of the dining tables.

Now before moving on to making your own indestructible version of the Death Star, please be mindful of the dangers of working with cement mix and be sure to take all safety precautions when working with the mix. Cement mix doesn't taste very good (Believe me, it doesn't) and it can actually cause a lot of harm if you inhale or swallow too much of the dust or the mix. Wash your hands after handling the mix and wash again before eating, drinking, or touching your face. It's also important to wear goggles, gloves, and something to cover your mouth to keep the dust out. Please note that I am not responsible for any damage done to either you or to your environment as a result of this project. Be sure that you have a ventilated and safe place to work.

Step 1: Materials

To make the Death Star, you need materials. Simple, it is. (There's a joke there).

It's not enough to break the bank, but unless you have some spare cement mix laying around you'll be spending about $20. You will need:

  1. Latex Gloves (Makes washing up a lot easier and protects your hands from the cement)
  2. Goggles
  3. Breathing Mask
  4. Cement All Rapid Set Mix (I used two 25 lb boxes. Each box makes approximately 32 and I found these boxes quite easily at The Home Depot).
  5. Plenty of Water
  6. A mixing cup (I was using a quart sized mixing cup)
  7. A hardy mixing spoon
  8. Death Star Ice Cube Moulds. Available online through a variety of websites (Again, Amazon. It's reliable and trustworthy).
  9. A hammer
  10. A work area you don't mind getting dusty or accidentally spilling concrete on
  11. A refuse box is helpful

This is all that I used in the process of making all 60 Death Stars. You don't need to add anything extra to the mix when mixing the cement. Note that it also sets really quickly (to the point that it becomes hard to mix), especially if there isn't enough water to keep it hydrated. I didn't try any other cement mixes, but I know that some of them will take much longer to cure than the brand that I used in this instructable. I know that one of the original posts I mentioned earlier said to use Quikrete Countertop Mix, but after 60 successful attempts with the Rapid Set brand I highly suggest to opt for it from the start. With this brand, after 30 minutes of preparation between batches, each batch can cure in about 30 minutes to the point where it can be handled roughly and still retain its shape. It flows well when mixed right and completely fills in all the little crevices in the mould.

Note: I found the hole in the mould to be too small to pour cement into, so I cut the hole a lot larger. It was large enough for my mixing spoon to slide right in to pack down the cement (More on this later). You can do this without sacrificing the look of the Death Star. I enlarged the holes to about an inch and a half (1.5 inch) in diameter.

Step 2: Mixing: the All-important, Make-it-or-break-it Step

Disclaimer: A lot of the mixing was done experimentally with a whole lot of trial and error. I cannot give exact measurements for what to add (There are a lot of factors that can change the way the cement mixes, so measurements are sort of obsolete in my opinion), but I will teach you what to look for and how to tell if your mix is ready to pour. I apologize for this discrepancy.

Note: Not a lot of time sits between the point that the cement mix and the water are introduced and the point that the cement hardens beyond use, and during this time the cement needs to be placed into the mould. As such, mixing and pouring needs to be done quickly and accurately, so I suggest reading through the rest of this instructable before doing anything and potentially wasting a batch of Death Star material.

To start, pour enough water in the mixing cup to fill it to about half an inch to an inch high. It is important that you do this first. Pouring in the cement mix first will form a layer of clay-like material that'll be waterproof, i.e., the water will not reach the bottom of the mix in the cup and mixing will be almost impossible. Pouring the water first and then the mix will ensure that every bit of the cement mix will be in touch with the water.

Scoop in about enough cement mix to get a little island in the middle of the cup. At this point you need to start mixing. You'll know if you've added just enough if right after you start mixing the cement mix turns hard and starts to lump together, yet if you continue mixing the mixture will turn out smooth like a nice chocolate smoothie from Wendy's. At this point, 1 of 3 things will happen and will affect what you do next:

  1. If the mix is just as I described earlier (lumping, then smooth), continue on.
  2. If the mix is too watery and doesn't harden or lump up, add some more mixture until it does.
  3. If the mix is too lumpy and obviously needs more water (It's very easy to tell), add some more water, but only a little bit at a time. Seriously. Adding too much means you have to add more mix. I can't tell you how much mixture I wasted by accidentally adding too much water. Add little amounts until the mix is just right.

Essentially, what you're looking for is something drippy, but not droppy. When you're mixing the cement, lift up the spoon and study the mixture's behavior. You want something that drips or flows nicely, easily, and uniform. You don't want something that produces distinct drops as the mix falls when you let the cement flow off of your mixing spoon.

Step 3: Casting

Once you've confirmed that the mixture consistency is up to par, you need to put it in the mould quickly before it has time to settle. No need for a funnel, just pour the mix into the mould. It helps to keep the cup elevated above the mould so the mixture can pour as a single strand instead of a lump. Fill it up until you have some space at the top of the mould. Then, take your mixing spoon and pack down the mixture into the mould while holding the mould itself so that it won't separate under the pressure you'll be making. Get it at different angles to make sure that every crevice has been filled and the mixture fills the entirety of the mould. Your Death Star will not be smooth and/or will have plenty of bullet holes due to trapped air bubbles if this is not done carefully, so pay close attention to this part of the process.

Once you are satisfied with packing down the mixture, top off the rest of the space. Sometimes I only topped it off to the top of the mould, sometimes I let it overflow. Topping it off to just the top of the mould will give your Death Star a flat bottom, while letting it overflow will give it a cool looking rock formation to sit on, as in the pictures.

It is at this point that little Stormtrooper engineers get to work on the material you granted them. Give them about 30 minutes to 1 hour's time and the moulding will be strong enough to handle. You can tell if it's ready by pressing your fingernail into the exposed cement. If the cement makes a dent then give it some more time. If it doesn't and you hear that familiar tapping against concrete sound, the mould is ready to be taken apart. You can also test the concrete with a hammer if you let the concrete overflow, like I did. If, when you hammer the concrete, it falls apart like stone and doesn't crumble like wet sand, the mould is ready to take out.

Warning: I have come to the conclusion that the chemical reaction between water and cement mix is an exothermic reaction, and I have reach this conclusion based on observation. It makes sense since the liquid-like cement mix gives up it's energy to become a solid. As such, the Death Star will be uncomfortably warm if you take it out of its mould just after it has cured enough to be handled. This might startle some of you causing you to drop it. It hasn't happened to me, but I'm just warning you now.

Step 4: Finishing

The last step will be to clean up any excess concrete that may have formed on the Death Star's equator or on the base. This step is to make it safe for any curious passing Jedi/Rebel that might be wondering if it's a moon or not, plus it makes your sculpture more visually appealing. Gently tap into the protruding concrete, i.e., straight into the sphere rather than from the side of the excess cement. This ensures that you don't hit what you don't need to.

Once it's all clean, you're all set! Go forth, destroy, and thanks to you for reading my highly text-intensive instructable. May the force be with you.