Metal Casting – 3D printed ABS molds to be eliminate with acetone


For some time, I have been working for a way of creating metallic parts from my 3D printer. I wanted to find an easy, fast and simple way of getting metallic parts without a laser. I have been trying to print directly in tin, but it didn’t worked.

Here I will explain how to use low melting point alloys. In this example is an alloy of lead, bismuth and brass that melts at 140ºC.

Metal Casting – 3D printed ABS molds to be eliminate with acetone

This is very simple. The only thing you need to do is instead of printing your part, you print a mold of your part in ABS. Once you have it, you melt the metal and fill the mold with it. Then wait till metal is cold and submerge the mold with the part in acetone. This will melt the mold and you will get the metallic part.

Let me try to explain it better with an example. In this case we will cast a Pikachu.

  • Create the mold – First we need to draw or download our part. But we don’t print it. What we do is drawing a cube to cover or part and we subtract the part to this cube. This will be our mold. It’s important to keep one part open so we can fill it. Another important thing is to have some place were to have extra material because when metal cools down it reduces the volume (I didn’t do it on mine …). Once we have this we print it. Resolution is a very important parameter, because otherwise we will have a lot of marks on our metallic part.

Pikachu  Molde Pikachu  Molde Pikachu ABS

  • Hold the mold – Then we need to find a way of fixing the mold while we fill it. Is important to not hold it with the hand because melt metal can be dangerous … The mold of my picture is not the same as Pikachu but you will see a way of holding the molds.

Molde listo

  • Melt the metal – We need to melt the metal. In mi case I have used a blowtorch and a saucepan. Price for both components was less than 20 euros. You just need 140 deg, so is not complicate to get it. Even some electric ovens and cooking devices can get this temperature. We need to get a liquid metal so it can fill completely the mold.

Equipo fundicion

  • Fill the mold – Filling the mold needs to be done slowly, so you allow the air inside the model to escape. Otherwise you will have bubbles. It’s also important to give some soft hits to the mold so we help this air to go out and the metal can fill everything. If you have any other advice about how to model please share with us ;). Then you wait for the metal to cool down. It doesn’t take a lot of time, but it will depend of how big your part is.
  • Dissolve it in acetone – Then get a glass recipient (something that can be closed) and fill it with acetone. What you will have to do is submerge the mold inside the acetone. That will melt the ABS away and you will get the final metallic part. This process is slow.

Acetona 1  Acetona 2

And you will have your metallic part. Easy, right?

Here you have the pictures of mi Pikachu:

Pikachu 1  Pikachu 2

Pikachu 3  Pikachu 4

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