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Sharing a New Trick with the 3D Printing Community

Ok, below is the technique I’ve been working on – a novel, cheap, two-part mold method.

Making a cheap reusable two-part mold using a 3D printer and a laser cutter:

In this method we will be making a two-part mold for casting a clear bottle around a full color 3D printed artistic liquid. The finished object is a 3D inspired version of the red potion from the original Legend of Zelda.

The casting material for this project is clear silicone rubber, however, I’m confident that this method can be used for many materials. There are so many possible applications, from cheap movie props to casting lenses. I really hope all of you will run with this and cast some cool stuff.

What you’ll need:

1) 3D Printer that prints ABS (PLA will not work)

flasforge

2) A laser cutter or access to one, low powered hobby versions are fine

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There is also a online latex laser cutting service.

3) Acetone

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4) Q-tips

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5) 0.4 mm latex sheeting, I got mine from Etsy

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6) Gel Control Super Glue

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7) Encapso K from Smooth-On or other casting material

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10) Gloves for working with Encapso K

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8) 5mm x 50 mm bolts and 5mm Nuts

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9) Ratchet with 5mm socket and needle nose pliers for tightening bolts.

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The Method

First you will need to print the two parts of the mold. The mold for the bottle was modeled in Tinkercad.  The file is available here on Thingiverse. You will need to print two of them. If creating your own mold for another project use mine as an example.

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Now that you have two sides to your mold you need to smooth the surface that will come in contact with the casting material.

Do this by dipping a Q-tip in acetone and gently rubbing the surface until it has a smooth sheen after drying. Note: This can not be done with PLA as it does not dissolve in acetone.

It will look like this when dry.

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Great, you almost have a 3D printed two part mold. The problem now is that the mold is bound to leak because, even with great pressure, the two surfaces will not seal together. This is where the latex sheeting comes in. However, before we can use it on the mold we need to laser cut it. Some of you are thinking, “how am I suppose to generate a image to laser cut from a 3D model. Am I going to have to draw it?” The answer is no. Using Tinkercad, it is possible to position an object so that the workplane intersects its surface and can export it as a 2D .svg file.

Laser cutting files for the bottle mold are available here.

Once you have the .svg file you can easily convert it to the format your laser cutter prefers. Congratulations, you have just transferred a surface from a 3D model into a 2D file that can be laser cut.

For the bottle mold the results look like this.

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Now you must attach the latex to the surface of the molds. To do this, paint a layer of gel control superglue onto the mold and then carefully overlay the latex. (FYI, if your thinking about using liquid latex instead of latex sheeting, it will only work once, when you de-mold it will tear off)

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Once the superglue dries, it’s time to mold.

Most objects will go through the molding process only once. However, since we are imbedding an object into our bottle it will go through the process twice.

Bolt the mold together, making sure it is aligned. It needs to be tight but not too tight. Also, you can use clamps but this adds to the cost of the process. If you design your molds for use with clamps remember you still need a way to align the mold.

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Mix the Encapso K silicone per the directions. A total volume of 30ml will do fine. Once mixed, pour in enough silicone to cast the top portion of the bottle and allow the silicone to cure for 24 hours.

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Once curing is complete, de-mold. Notice how the latex layer stays in place, as this mold is truly reusable.

The results look like this.

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Place the 3D printed potion liquid in the mold like so. You can purchase the blue or red liquids here.

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Align and bolt the mold back together.

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Mix the Encapso K silicone per the directions. A total volume of 40ml will do fine. Once mixed pour the silicone till it reaches the top of the mold. Using chop sticks make sure the potion liquid is positioned in the center of the mold.
Allow to cure for 24 hours. De-mold and remove your potion!!

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This method is free for all to use, enjoy and create something great!!!

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Adding the cork to the bottle.

What you need

1) 9/16 x 27/64 Sealing Cork #3 (Available at most hardware stores)

2) Razor blade

3)Encapso K

Using a razor blade, cut a cork to the desired size.

Using the razor blade, very carefully remove some of the silicone material at the top of the bottle so the cork can be set in it. Next, mix up some Encapso K and use it to glue the cork to the bottle.

The final result looks like this.

bottle2 bottle

Alternative method

Alternatively to make the bottle you could use a traditional silcone molding technique.

Instructions can be found here.

Smooth-On Mold Making: 2-Part Mold

You will need a bottle blank to cast from. You will still have to use a 3D printer to create it.

The file for the bottle can be found here on Thingiverse.

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That was a lot of work. I need a break. Posts will continue as usual starting on Monday!

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