This month at Proto-Pasta we're going more in-depth on finishing the awesome metal composites we make here at Proto-Plant! Specifically, Copper Fill is our material of choice because it's Fall and who doesn't want a beautiful shiny copper pumpkin, right? There is a lot that goes into making a little pumpkin look so cool but don't worry this Instructable will guide you through all the steps from printing to polishing and everything in-between!
Let's talk about Proto-Pasta's Copper Metal Composite
One of the most highly desired aspects when 3D printing is filament performance from the build plate to the finished design. Our Copper filament prints like plastic, but finishes like real metal for beautiful, durable parts from most standard 3D printers. In addition to the awesome methods that we will be using, there are several more on Proto-Pasta's filament information page. Copper Information
Step 1: Choosing a Pumpkin Model and Printer
Before we start printing
First, we have to start by creating our masterpiece on the computer before we can begin the hands-on steps.
Let's start by finding a pumpkin model from Thingiverse.
We have already located an awesome model from 3DWP and transformed a few of the pumpkin's features for an easier printing process. To do this we inserted a cylinder into the base of the pumpkin to create a flat surface for our first layer. You can find the transformed model here .
Now that we have a pumpkin we need to decide what software and hardware we are going to use to bring it to life. Here at Proto-Plant, we used our Ultimaker 2+ along with the Ultimaker version of Cura. Starting with basic PLA settings provided by Cura, we then tweaked them as we went along tuning the printer for best results.
NOW START PRINTING!
Step 2: Finishing Our 3D Model
There are three super cool finishing techniques we will be using on our pumpkin and with a little patience, we can transform our 3D print from ordinary to extraordinary.
Before we get started there are a few tools and materials we need to gather.
1. Wire Brush We will be using a wire brush to achieve our first finish and prep the surface for oxidizing.
2. Oxidizing Solution Consisting of vinegar, hydrogen peroxide, and salt, the oxidizing solution is used for turning the surface of our pumpkin to a nice patina - kinda like the statue of liberty or an old penny. (we will be mixing this in a small container)
3. Paper Towels Used for applying the oxidizing solution.
4. Sandpaper We will be using sandpaper for taking care of those annoying layer lines and polishing the surface to add a shimmering glow. (120-grit all the way to 8,000-grit) The polishing paper is available from Proto-Pasta
5. Clear Coat Acrylic Once we are done with the finishing steps we will use a clear coat to protect the surface.
Step 3: Brushed Surface
Let's start by using our wire brush to rough up the filament. In doing this we are exposing the copper particles encapsulated in the plastic. This is the first step to a great result so be thorough and brush it until the surface is speckled.
Brushing the outer surface of the filament will create the base for oxidizing and polishing but it also serves as a super cool finish, showing more characteristics of the print and it's super easy!
Step 4: Oxidizing (patina)
Creating the Solution
Now that we have created the brushed base we can begin to transform the color of our pumpkin. For this, we will need a few more materials. This is where the oxidizing solution is needed. The solution consists of vinegar, hydrogen peroxide, and salt. Starting with the vinegar and hydrogen peroxide mix the 2 liquids at a 50/50 proportion in a small container. Now add enough salt to make the mixture thoroughly saturated.
To get the coolest and quickest effects from oxidizing we will be using several paper towels to mummify our pumpkin.
Start by soaking one paper towel at a time into the solution and wrapping it around the pumpkin. Layer several wet towels around the pumpkin until all of its surfaces are covered. Let your mummy pumpkin sit overnight in the open for the oxidation process to take place.
Once the pumpkin has dried peel back the paper towels and gently rinse the pumpkin under the faucet. It might look like the blue-green color is washing off but don't worry it will quickly reappear once the pumpkin has dried again.
Step 5: Polishing
Polishing your copper pumpkin will take the most effort out of all three finishes but is by far the most rewarding!
In order to achieve a mirror-like shine, we will be using a few more tools. This is where we will be using our assorted sandpaper. (120 grit all the way to 8,000-grit) Starting with the 120 grit, sand down the surface to remove all the layer lines. This is very import because we won't be able to get a perfect finish if they aren't gone.
The key to achieving a perfect finish is to make sure you sand away all the lines from the previous grit. You should be able to notice them getting smaller and smaller until the last grit makes them completely disappear.
Next, we will use the 6 polishing papers included in Proto-Pasta's, Polishing Kit . Thoroughly work through all 6 grits in order from 400-8,000.
• 400-grit (yellow)
• 600-grit (gray)
• 1,200-grit (blue)
• 4,000-grit (pink)
• 6,000-grit (teal)
• 8,000-grit (white)
Now that you have a smooth shiny pumpkin, you can help to preserve that finish with an acrylic clear coat spray. (Warning: Using a clear coat may dim the surface. If you want to keep the pumpkin surface shiny without harming it we recommend buffing the surface with the highest grit every time you want to display the pumpkin)
Place your pumpkin outside or in a well-ventilated area and coat the surface in several layers allowing time to dry in-between.