Makers and DIY enthusiasts have access to more materials for their projects than ever before. 3D printers make it incredibly easy to work with plastics and rubber, and materials like wood have long been a staple in this hobby. But what about concrete?

Usually reserved for large-scale building projects, concrete is a material many DIYers won’t consider for their tech projects. You can use it to create various objects, from ornaments (like the base of a DIY smart lamp) to electronic boxes to house your projects. You can get started right away if you already have a 3D printer; find out how below.

Why Use Concrete for DIY Tech Projects?

Concrete has been around for a very long time. It’s well known for its versatility, providing many of the benefits of solid rock without having to be sculpted. Instead, you can use molds to form concrete shapes, making it a material that just about anyone can use at home. Of course, though, there are more benefits to this material that can easily be overlooked.

• Strong and long-lasting: Unlike 3D-printed plastic, concrete is incredibly strong once it has cured and can withstand significant damage. It is also waterproof once it cures, making it great for use inside aquariums and fountains.
• Easy to color: You can make your concrete colorful with the addition of pigment powders when you mix your cement with water. It’s worth experimenting with this before you try to make a finished product.
• Unique: Creating objects with concrete is far more involved than 3D printing something, giving you greater control over the finished product while also making it easier to influence it as it takes form.

Despite its benefits, there is a time and a place for concrete. The tips and tricks revealed below will give you a good idea of how to create 3D-printed molds for concrete, along with some advice to help once the concrete is poured.

How to Design 3D Printable Concrete Molds

Designing a 3D printable concrete mold is easier than you might expect, but there are a few approaches that you can take. The more molds you make, the more you will learn about the process, and it should get easier to create successful molds.

• Create your intended object first: 3D modeling tools make it possible to create a model of your intended finished object before you build the mold. Taking this approach will make it significantly easier to produce molds that match the specifications of your object, while also giving you the chance to see it before it is made.
• Breakaway molds: Unless you plan to dissolve or melt your mold, you will need it to break apart to get the concrete out once it has cured. This makes it more complicated to design your model. Nuts and bolts can be used to secure the mold together during the pour and while the concrete cures. You should always plan for how you will take the mold apart before printing it.
• Consider seams and leaks: Thanks to the need for a mold that can break apart, there will be seams that have the potential to leak when the concrete is poured. Using thicker concrete can help with this, but it will also be worth covering as many seams as you can with other parts of the mold.
• A rigid mold: It’s likely that you have fairly tight tolerances in mind for your project, especially if you are creating a DIY electronic box from concrete. This will be much easier with a strong, rigid mold. Use outer braces along each edge of each piece of your mold to ensure that they don’t bend.
• Avoid overly fine detail: Concrete is a strong material, but it can crack and break apart if it is too thin. 1cm wall thickness is a good place to start with concrete. You should also consider using curved or cut corners when objects aren’t round, to make them stronger.
• Consider a plastic core: Concrete adheres to a lot of materials, including plastic. Using a 3D-printed core for your model can save concrete, make the model stronger, and make it easier to remove your mold from the finished design. You can afford to have thinner concrete walls if your model has a plastic core.
• Be patient: Working with concrete molds is unlike anything else in the 3D printing hobby. It will take time to learn, and this makes it worth preparing yourself to be patient with the process before you get started.

These tips will give you a head start with your concrete mold production, but you will have to do some learning for yourself. There are loads of videos and guides around the web to help you with 3D printing, and plenty that relate to concrete, giving you a wealth of resources to draw from.

Choosing and Mixing Concrete for 3D Printed Molds

The concrete you choose for your 3D-printed molds will always impact the finished result. There are several issues to consider when you are choosing concrete for your project, ranging from cure time to the size of the materials that make your cement.

• Cement coarseness: Cement is made from a range of ingredients, including sand and stone. Some cement mixes are coarser than others, with larger pieces mixed in. 3D-printed molds with fine detail benefit from finer cement, while larger designs can cope with coarser options.
• Cure time: Cement cures into concrete when it is mixed with water. This process can take anywhere from a few minutes to several days. Working with slow-curing concrete is a good idea when you first get started, ensuring that you have plenty of time to fix mistakes and ensure that your mold works properly.
• The right mix: Different types of cement require different ratios of water to work. This means that you have to follow the instructions that come with your mix to get the best results. Thicker concrete will be harder to pour but will be less likely to leak from your mold.

Curing and Finishing Your Concrete

The final part of this process involves curing and finishing your concrete. Most concrete takes a very long time to cure fully, with many mixes getting harder and harder for as long as a century. In reality, though, most of the concrete you find in stores will cure enough within a couple of days.

Patience is key here. Your mold will be extremely hard to remove without causing damage if the concrete isn’t cured properly, but it won’t make any difference if you over-cure your mold. Be extremely gentle as you remove the mold from your new concrete object.

Once your object is out of the mold, you have a lot of finishing methods to choose from. Sanding your concrete will make it smooth, while coating it in epoxy or PVA will harden and protect it. Choose a finishing method that reflects the desired outcome of your design and follow guides online to help you to achieve the right results.

Making Things Out of Concrete

Concrete is a rather exceptional material, offering the strength of stone while being relatively easy to work with. Of course, though, you will still need to learn a lot along the way, and working on your own projects is an essential element of this process.