Finishing Pure Metal Parts

Parts printed with metal based filamet can be finished in several different ways. They can be finished for show and to be used in some applications in their green state, and they can be finished after sintering.

Finishing Sintered Parts

Tumbling: Tumble the part in a standard gem tumbler and Stainless Steel media. For this rotary tumbler, use 0.5kg tumbling media, enough water to cover parts and media + 25mm, and 15-20 drops of Tumbling Liquid (Measurements are approximate). Tumble for 30-60 minutes. Rinse the part in plain water after tumbling to get rid of the soap and ammonia.

Wire Wheel: Use a brass wire wheel to grind down the surface of the part to smooth it out.
When using a wire wheel, practice good industrial hygene as there will be airborne particles.

Sewn Buffing Wheel: Polishing allows you to take the shine from the tumbling, or wire brush to the next level. Place a sewn buff on a rotary tool, then liberally apply a polishing compound, Zam is recommended, to the buffing wheel.
When polishing, practice good industrial hygene as there will be airborne particles.

Adding a Patina (Bronze, Copper): Any method used on copper and bronze to rapidly patina them should work. One tested method is soaking the part in a solution of water and liver of sulfur until the desired patina is achieved.

Adding Rust (Iron): Any way that you can make iron rust should work to rust your part. Soaking the part in water is the simplest method and provides results in several hours.


Finishing Green Prints

Manipulating Prints with a Soldering Iron/Wood Burning Tool: Use a soldering Iron or wood burning tool set to 190-245°C to manipulate green prints, add features, and weld parts together.

Manipulating Prints with a Heat Gun: Heating green prints with a heat gun allows for bending thin walls and reshaping features.

Manipulating Prints with a 3D Printing Pen: 3D printing pens can be used manipulate green prints and add features. It can also be used similar to plastic welding, to attach multiple prints together.

Filing: To make print lines vanish, sand the surface even. The loose particles from sanding are smashed into the print line gaps with the heat from the friction, fixing them in place. This step is complete once the entire print’s surface is smooth and even. Constant movement to different areas of the part is necessary when filing to avoid unintentional melting.

When filing, practice good industrial hygene as there will be airborne particles.

Sanding: Sanding is used to get your green part to shine. Start with 120 grit sandpaper, and go over every part of the print. The matte surface will become shiny as finer grits are used. Complete the entire surface of the print before moving to the next grit. Using 6 or 7 different grits of sandpaper is recommemded. A nice shine can be achieved with less, but the mirror shine comes closer to the 7, ending around 3000 grit. After sanding, rub the print down with some flannel or a polishing cloth to clean off loose particles. A mirror shine should be evident at this phase. Constant movement to different areas of the part is necessary when sanding to avoid unintentional melting.

When sanding, practice good industrial hygene as there will be airborne particles.

Polishing: Polishing allows you to take the shine from sanding to the next level. Place a sewn buff on a rotary tool, then liberally apply a polishing compound, Zam is recommended, to the buffing wheel. The print will melt if it gets too hot, so it is critical to keep the buffer moving and continue to apply buffing compound liberally. It may be useful to practice this step on a simple or partial print.

When polishing, practice good industrial hygene as there will be airborne particles.

Adding a Patina (Bronze, Copper): Adding a patina to a green print requires a little sanding first to expose the metal particles. Any method used on copper and bronze to rapidly patina them should work. One tested method is soaking the part in a solution of water and liver of sulfur until the desired patina is achieved.

Adding Rust (Iron): Rusting a green print requires a little sanding first to expose the iron particles. Any way that you can make iron rust should work to rust your part. Soaking the part in water is the simplest method and provides results in several hours.

If you will be sintering your print: Polishing before sintering is not necessary. Post-sinter, the print will behave as the metal it’s made of – file it, weld it, polish it.


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