Ordering a custom silicone mold is expensive and takes a long time. Typically when I need a silicone mold I don’t need an industrial grade product, something made from home usually works just fine for most of my applications.
Making a silicone mold from 3D printed parts is really not difficult and can save you tons of money, follow this guide for step by step instructions on how to make a high quality and affordable silicone mold.
Step 1 – Print The Object You Want To Mold.
3D print the item that you want to create a silicone mold from. You will need to pick a model that doesn’t have any enclosed bridges.
The simpler the better when it comes to silicone molds, ideally you would either print something that is flat like this hexagon shape that I am going to be using today that will be great as a silicone mold for resin drink coasters, or something that is more compact like a simple chess piece or a dice.
A 3DBenchy is a great example of a 3D printed part that would be terrible to mold in silicone. There are so many arches and holes in the model that would trap silicone and would rip the silicone when removing the part.
Step 2 – Create A Container For The Mold.
A mold container can be created from a variety of things including a Solo Cup, foam board, tupperware, or 3D printed. My preferred method is a glass storage container that has tapered walls.
If you want to 3D print a container you can create one in tinker cad or find one on thingiverse but my recommendation for a container is either to make a simple one out of foam board and hot glue or use a solo cup.
If your part has a large flat surface your will want to make sure the floor of your container is also flat so that the mold does not creep in on the part which will make your part harder to remove from the mold.
The benefit of using something disposable like a foam board or a solo cup is that the walls are very thin and easy to cut up when removing.
Step 3 – Place Your Part In The Mold Container.
Place your part in the bottom of the mold container so that the largest flat surface is at the bottom of the container.
You probably wont need any glue or tape to secure the part to the container but in this case I used a few drops of hot glue to make sure that the 3D printed part did not float to the surface.
Step 4 – Mix Your Silicone.
You can select any silicone that is appropriate for your respective application. If you are unsure which silicone you should use, this is the silicone that I am using and also the one I recommend.
You should follow the manufacturers recommendation for the ratio of base to catalyst and in this case it is a simple 50% base and 50% catalyst.
Make sure to set a timer to ensure that you do not exceed the working limit of the silicone, once the silicone starts to cure you should not be messing with your mold.
Tip – Put your base and catalyst in a disposable container such as a solo cup for mixing so that you can throw the container away after use.
Step 5 – Pour The Silicone Into The Mold.
Pour your already mixed silicone into the mold in a high and slow stream. Pouring your silicone correctly will prevent bubbles in the mold as well as prevent air pockets in the mold around the part.
You can also lightly tap the sides of your container to help any additional air bubbles rise to the top so that they are away from your part.
Step 6 – Wait For Silicone To Cure.
It is really important to be patient in the curing process, if you mess your mold before it is ready you might damage the profile of your mold.
The cure time for the silicone that I am using is 3 hours for demolding but I am going to leave it overnight just to make sure that it has plenty of time to completely cure.
One way that you can tell that the reaction is working is by hovering your hand a few inches above the silicone to feel for heat. It is pretty amazing how two room temp materials when mixed together produce a chemical reaction that produces heat.
Step 7 – Remove The Silicone From The Container.
Remove the silicone from the container by lightly pulling the silicone from the container on all sides to relieve the surface tension, then pull the silicone with equal force to release the floor of the mold.
You can use a spatula or a butter knife to lightly remove the silicone from the walls of your container.
If you are using a disposable container like a solo cup or hot glued foam board you can just rip the container apart, or cut it apart with scissors, to release your mold from your container.
Step 8 – Remove 3D Printed Object From Silicone.
Delicately remove your 3D printed part from the silicone mold. You shouldn’t have to rip the part out with a lot of force.
Typically you can lightly flex the silicone back and forth to remove the surface tension of the part to the mold then pull the part from the mold.
In my case the hot glue held the 3D print firmly enough to the bowl that the silicone and the 3D print seperated as I was removing the silicone from the bowl.
You can clean up any stringy or hanging pieces from your mold with a hobby knife. You will want to remove as many of these imperfections as possible to ensure that you will get a good end product when you go to make things with your mold.
Step 9 – Wash Your Silicone Mold.
Wash your silicone mold with warm water and soap to ensure that there is no remnant uncured silicone in your mold that could contaminate your next pour.
This is especially important if you are intending to use the mold for food such as chocolate, or for candles.
It is also important to wash your mold if you are intending on using it for resin pours. The resin may have a chemical reaction with remnant uncured silicone that could cause the resin to not cure properly.
Can an Ender 3 3D Print Silicone?
An Ender 3 can not 3D print silicone but can print flexible materials such as TPU 98A, TPU 85A, and TPU 58D. To create an object out of silicone you will have to create a mold and pour the silicone into the mold.
Creating silicone molds from a 3D print is simple and cost effective. With a mold the size that I produced I think I can get 3-4 molds which comes in at about $10 per mold. That is really a good price considering you would have to hire someone to make a mold for you that could cost up to $50.