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Sunday, 25 November 2012

Half Truncated Cube Build

I've really been wanting to do a proper shape modification on a twisty puzzle for a while now, and I finally managed to get around to doing it!

Now, I have no experience in these things whatsoever, so I picked up all the info I needed from useful sources like the Forum and Tony Fisher's YouTube Videos. And I was surprised to find that many of the more simple modifications are not actually that difficult to make.

I was given a spare, unloved, standard Rubik's Cube a while ago, and I knew that I would end up using it for my first shape mod. Then I had a look around to see what would be a nice puzzle to make as my first stepping stone into puzzle modding, and I decided to go with a Half Truncated Cube, which is essentially a cube which has had half of its corners removed.

Poor thing had no idea what was coming...
So, I started with a bog standard Rubik's 3x3x3, then I immediately proceeded by hacking off four of the corners!

In order to do this I had to cover the cube in masking tape so that it wouldn't move during cutting. I then drew on the lines I wanted to cut along using a pencil and ruler and checked to make sure everything was in the right place before making any cuts.

A not-quite Rubik's Cube

The cutting was done using my Dremel 300, which was surprisingly easy. The cube spits of some pretty hot plastic shrapnel during cutting, so if you're going to do this make sure you're wearing long sleeves and some kind of eye protection.

Here is the result of the cutting. The cuts don't need to be perfectly clean or accurate, and that would be hard to achieve anyway, instead I didn't cut quite up to where I had drawn the lines.

Once the corners had been removed I could use a flat power sander to sand the corners right up to the lines. This also made sure that the resultant faces were perfectly flat.

Now we have our Half Truncated Cube shape, but there is still the small matter of the fact there are holes in the puzzle, because all those cut pieces were hollow.

Pieces filled with Milliput
This problem is rectified with some wonderful stuff called Milliput. Milliput is a type of epoxy putty. It has the texture of the sticky tac you put posters up on the wall with, and it comes in several different colours. Since my cube was black it seemed best to go with the black variety. You thoroughly mix the epoxy from two parts, then you can use it immediately. I used some water to help with the moulding as it gave the Milliput a kind of clay-like texture which enabled me to get a much smoother finish along the edges of the pieces, and it stopped it from sticking to my fingers.

Each piece of the cube (apart from the centres  needed filling, and this would take a lot of Milliput to achieve. It seemed like such a waste to use so much of the Milliput, so instead I mostly filled the pieces with white sticky tac, then filled the last part up with Milliput. This dramatically reduced the amount of Milliput used.
As you can see I took the cube apart for this bit as it was easier, and this way there was no chance of me accidentally sticking different parts together using the epoxy. I left the parts overnight, and by morning the epoxy was rock hard and ready for sanding again. It actually sets in four hours, but I wanted to be sure.
At this point I could remove the white sticky tac from inside the pieces using the hole at the back of each piece. This way it makes the puzzle much lighter again, and I can reuse the tac for my next project.

Sanded again and sprayed black
As you can probably tell from the picture, I had slightly overfilled each piece with the epoxy to leave a margin of error, so I once again needed to sand the pieces flat. I reassembled the pieces back into their original shape and used the flat power sander to sand off the excess black epoxy.

Sanding black Milliput kind of gives the pieces a grey finish, so to bring back the colour uniformity I gave the whole puzzle a coat of black modelling spray paint. This made the grey pieces black again, and also gave the whole puzzle a nice matte finish.

From a previous project I worked out that it was better to give the puzzle this light coat of spray paint while it was still assembled. A light coat of paint done from a distance will not stick the pieces together at all. It will give the whole puzzle a nice even finish and also the paint won't land on any of the internal edges, so the cube will turn just as well after painting as it did before.

All that was left to do now was to add some new stickers! Luckily, because this is such a popular design for many first-time modders, there were already stickers available. This is lucky because otherwise I would've had to painstakingly measure and cut each sticker by hand, and that would've added many hours onto the build time.
I ordered my stickers from OlivĂ©r Nagy who runs a website called Oliver's Stickers. It is a brilliant website! He supplies a massive range of puzzle stickers, and will even make stickers to order if you come up with a new design. So for just over 2 Euros I saved myself having to do a lot of extra work!

The stickers arrived a few days later, and after ten minutes or so of stickering this was the result:

I'm very happy with how my first puzzle mod turned out, plus I had a load of fun making it! The total cost of materials for this build probably came to less than £10, and for that I get a new puzzle for my collection that I can proudly say I made myself.

This certainly won't be my last build, and if you haven't given it a go yourself yet then I highly recommend that you do. You'll have great fun, and there's nothing more satisfying that seeing a puzzle come to life that you've made yourself.


  1. Oli, wow, great job!...your half truncated cube looks like something you bought new...from the photos I cannot tell its been cut down from a standard Rubik's cube..the whole job looks very professional. Glad your first project is a success...there is nothing like creating your own puzzle that works! Keep up the mods!

  2. Beautiful job Oli! Next you need to make a set of them right up to 9x9! Or how about making a ghost cube?


  3. Thanks guys! I'm very happy with how this went. Now I'm just trying to decide what to make next. A Ghost Cube is certainly a possibility!

  4. wow ! Then Next you need to make a set of them right up to 9x9 ! for making a ghost cube, is not?


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