Hi my name is Sean with MakerBot Learning.
Silicone molding is a very powerful technique if you're looking to make many of an object,
or make something in materials not supported by your 3D printer.
In this video, we'll show you some of the best practices associated with creating a
mold around a 3D printed part and then casting into it.
To create a mold around a 3D print, you'll need the following: a 3D printed mold box,
hardware & keys, the master or the print you are molding, silicone, resin and optional
dye, cups for mixing and measuring silicone and resin, mixing sticks, mold release spray,
hot glue or cyanoacrylate, funnel, x-acto knife, rubber bands tapes or straps, gloves,
a respiratory mask, and eye protection.
First, we will show you how to create a mold with a round of 3D prints.
For our print, we chose the top of a perfume bottle.
Here you can see the printed part versus the parts created by silicone molding.
When pouring the silicone to create your mold, you need to create a box or container to mound
the mold.
You can use form core board, LEGOs, or a cup depending on the size of the model.
We decided to 3D print ours.
Our mold box included a printed pour spout.
If you're using form core or LEGOs, you'll need to make room to pour resin when creating
your mold.
You can use a funnel to do this.
The silicone molding process doesn't require any special settings so we show our default
settings in MakerBot Print.
Spray all mold components with mold release.
Your model will need to be suspended in the mold.
You can suspend your model using printed sticks like the ones shown in grey, you can also
use toothpicks, skewers, or popsicle sticks.
Using superglue and activator, you can glue the sticks to your model.
Once you've suspended your model in your mold, spray the entire form with mold release.
This will ensure your model can be removed from the silicone mold.
Now that you've prepared your mold box, you are ready to select and prepare your silicone.
We chose a two-part silicone that needed to be measured before pouring.
We found the volume of our mold by pouring water into it, and then pouring that water
into a measuring cup.
For best results, we recommend doing this in a room temperature environment.
Once you have measured evenly, pour both parts into the same cup and mix thoroughly for 2-3
minutes.
Be careful not to mix too quickly or air bubbles will be created, which are harmful to your
mold.
Be sure to look for the pot life of your silicone.
This will tell you how long after you mixing the parts together you have to work with the
silicone before it cures.
Our pot life was around 3 minutes.
Thoroughly mix and pour the silicone into the form you have created.
We recommend starting to pour at one corner and slowly pouring until the silicone reaches
the top of the first half of your mold box.
Once poured, we inserted 3D printed keys which will allow the mold to fit together once its
cured.
Depending on the mix you've chosen, once poured, the silicone may take between 4-48 hours to
cure.
We used a quick cure silicone that took only 75 minutes to cure.
Your mold is cured when it is fully solid and no longer tacky to the touch.
Once the first half of your mold is cured, you can repeat this process to create the
second half of your mold.
Next, remove the keys, spray the pour mold and mold box with mold release, attach and
secure the second half of the mold box, mix and pour silicone until it reaches the top
of your mold box.
Once both halves of the mold are completely cured, you can disassemble the mold box and
remove your mold.
Now that you've removed the mold from your box, inspect it for any air bubbles or deformitie.
If there are air bubbles at the surface of the void, they'll be present in your cast
part.
Once you have removed the mold box and inspected your mold, close the mold and secure it- it's
essentially that the mold be sealed properly otherwise resin will leak during the pouring
process.
We plugged up our vents with wooden skewers.
We used rubber bands to hold our mold together during pouring.
Next, mix your resin.
Typically resin will come in two parts: a resin and a hardener.
They should be stirred separately and then mixed together.
Again, observe the pot life of your resin to understand how long you have to work with
it until it cures.
Our resin's pot life is 3 minutes.
Pour the resin through a funnel into the hole of your mold until it is completely full,
then let sit to cure.
Once your resin has cured, you can remove the form, spray the cavity with mold release,
and pour again.
You can repeat this process using the same mold until you notice irregularities or quality
issues in your part.
At this point, it might be time to remake the mold.
the more care you put in to creating your mold, the longer it will last and the higher
quality part you will create.
You've successfully created a mold around a 3D print and can recreate your model in
varying materials and quantities.
You just learned how to take your prints beyond the build plate.