3D printing - Making models for the decorative concrete industry

3D printing allows you to turn a digital model into a solid object. The model goes trough a “slicing” software which divides it into layers. The 3D printer uses the information and starts building the object layer by layer from the ground. Three-dimensional printing is an additive process. A process in which all of the material is used to create the desired shape - Additive Manufacturing.

Now, that we have the theory out of the way - here are two statements:

3D printing is an amazing piece of technology that allows you to create anything you like.

3D printing is an amazing piece of technology that allows you to create anything you like out of concrete.

Which one has more of a ring to it? Exactly!

I was recently contracted to make a model and a mold for a custom concrete sink by a UK based company - Concrete Etc. I’d like to take you on a journey and show you how I made it.

I started by 3D modelling the sink according to the specifications that I was given. The order was for a circle sink with the following dimensions - 370 mm diameter, 180 mm tall and 18 mm thick walls. Important part here was giving the sink a sloped base to ensure that the water will flow into the waste. Once I had the model created I was faced with my first challenge - actually printing this sink.

Now, 3D printing the sink wasn’t as straight forward as it sounded. There are very few 3D printers that are actually able to print this size at once and sadly I do not own one of those bad boys. My workaround was to slice the model into nine more manageable pieces. I came up with a pin alignment system and it looked like that:

After I checked, double and triple checked the dimensions I started the printers. I used 5 of my 3D printers for this project. It took a little bit over 130 hours of printing, but in the end, voila the sink model was a reality. As you can see from the images 3D printing leaves distinguishable layer lines that can be sanded and filed for a perfect finish.

Next was assembling the model and finishing it. The first part was pretty straight forward as the fit was perfect. Filling, sanding and polishing the model sink on the other hand were a bit more challenging. This is the most important part of the build. You want, no you need your model to be flawless as it will be molded and every single cast will be as perfect or imperfect as your model. This part takes a lot of patience and as a general rule - the more time you put in, the better it will look like. I stopped at a mirror-like finish.

Once the model was ready it was time to mold it. Now, I wont be going into detail with the molding process as it is really specific and deserves a separate post. If you’re curious now though, you can check the follow post - What is a sleeve mold and how it's made. And without further ado here it is the first cast of this unique sink. What started as a 3D model or even a sketch on a piece paper is now a real concrete sink!