How to Waterproof 3D Prints

Typically, water and 3D printing don’t mix. But you’ll be surprised to know that you can waterproof your 3D prints, strengthening them against rain and moisture. No need to keep printing a new replacement for the 3D prints you’ve worn out! Here’s how you can extend the shelf-life of outdoor 3D prints by waterproofing them. 

Step 1: Choosing the right materials

Some 3D printing filaments are averse to water that no waterproofing can save them. Prints made of hygroscopic filaments will bloat and deform when in high-humidity situations or when it comes into contact with water.

It is also important that the 3D prints are smooth, making it hard to apply waterproofing solutions on the surface. So filaments that are vulnerable to deformations and chemical reactions are not recommended.

We recommend the following 3D printing filaments:

• PLA: PLA should work fine as a waterproof 3D print. However, you have to be careful that it doesn’t get exposed to hot water or conditions as they can easily melt. One example of a waterproof item you can create with PLA is a soap dish. 
• ABS: ABS is also a good waterproofing material. What you have to be careful though is not to expose the ABS-made prints to the cold as it can cause cracks and deformities. 
• PETG: PETG is the best filament for waterproofing. This filament already has waterproof properties but it also has superb thermal resistance. With waterproofing, whatever you make with this filament will last a long time. 
• Food-safe filaments: If you’re planning to create waterproof items that will come into contact with food and drink, you can choose food-safe PP and PETG. 
• Heat-resistant filaments: If you’ll be creating items that will need to withstand high heat, you can use ABS and PETG. 

Step 2: Tweaking slicer and printing settings

• Extrusion: Over-extrusion reduces the gaps in your 3D print, therefore, making it more waterproof. You can do this by increasing the flow rate or extrusion multiplier in your slicer. To further prevent gaps in between layers, you can also increase the temperature. 
• Nozzle size: It is recommended that you use a wider nozzle when creating waterproof prints as it creates thicker extruded lines, meaning a reduced chance for gaps and holes. 
• Infill & shells: More shells mean thicker walls for your print. This will help protect the interior of your print. Increasing the infill percentage will also make your print more solid and retain its form and structure. 
• Layer height: Increasing the layer height also reduces gaps. The lesser the layer lines, the more solid your print is against water.

Step 3: Post-processing

After creating a solid and dense 3D print, it’s time to treat it with chemicals to ensure that water doesn’t get into your print. It is important to smooth the layers and apply a protectant to make your print stand tough against water damage.

Here are the post-processing methods you can do to improve waterproofing:

• Acetone: Acetone is a popular method of layer smoothing for ABS, Polycarbonate, and ASA. We recommend using only high-quality ABS for this method. Here’s a guide on how to do Acetone Vapour Smoothing.
• Epoxy:  Epoxy resin acts as a protectant that waterproofs a 3D print. It also smooths the layer lines to prevent water from penetrating the item. 
• Wax: If your 3D prints still have cracks and gaps in between the layers despite your best effort, you can use wax to fill them up. 

Step 4: Test-drive your waterproof 3D prints

Now’s the moment of truth, it’s testing time! This is where you’ll know if your 3D print is truly waterproof. Soak your 3D print in cool water for a couple of hours. Leave it to dry for an hour. If you don’t see cracks or deformities on the surface, then congratulations, you have created a waterproof 3D print!

However, if it’s the opposite for you, you can revisit the steps above to get it right. 

Get waterproof 3D prints with these 3D Print Waterproofing Tips!

How did it go for you? Let us know in the comments below.