How to Make Silicone RC Tires at Home With a 3D Printed Mold

In this project, I’ll show you how to make custom RC tires at home using a 3D printed mold and two-part silicone rubber.

The best part is that you don’t need expensive workshop equipment. There is no vacuum chamber and no vibration table. All you need is a 3D printed mold either FDM and suitable two-part silicone.

The process includes assembling the mold, calculating the amount of silicone, mixing and coloring it, allowing the larger air bubbles to rise, slowly filling the mold, curing the silicone, and removing the finished tire.

The result is a soft and flexible RC tire with well-defined tread and good traction.

You can watch the complete process in my video:

How to Make RC Tires at Home | 3D Printed Molds

For this project, I used:

1. Two-part liquid silicone rubber, 27A, white
2. Black pigment
3. 3D printed RC tire mold
4. FDM 3D printer
5. Small digital scale
6. Mixing cup
7. Mixing stick
8. Clamps or rubber bands
9. Small flat screwdriver
10. Sharp hobby knife or razor blade
11. Side cutters

Always use the mixing ratio specified by the manufacturer of your silicone. Some silicones are measured by weight, while others are intended to be mixed by volume.

If you are looking for available RC tire, wheel, and mold STL files, you can visit my Patreon page:

RC Tire Lab on Patreon

Start by putting all parts of the tire mold together.

Secure the two mold halves with clamps or a couple of rubber bands. The important thing is making sure both halves stay tightly closed while the silicone is being poured.

Check that the mold parts are correctly aligned and that the pouring funnel and air vents remain open.

Before mixing the silicone, calculate how much material the tire requires.

Open your slicer and import the tire model. The tire does not need supports for this calculation.

Click Slice, and then check the model statistics to find its exact volume in milliliters.

For the silicone used in this project, 1 milliliter was approximately equal to 1 gram. This made it possible to use the volume shown by the slicer to estimate the required weight.

Remember to add a little extra silicone for the pouring funnel so you do not run short while filling the mold.

Place a mixing cup on a small digital scale.

For this tire, I measured:

1. 36 grams of Part A
2. 36 grams of Part B
3. 72 grams in total

I prefer measuring by weight because it is a little more accurate for the silicone I use. If your silicone is designed to be mixed by volume, follow the manufacturer’s instructions instead.

Because my silicone is white, I added a small amount of black pigment to give the finished tire a realistic rubber appearance.

Mix everything thoroughly. Scrape the sides and bottom of the cup so that Part A and Part B are fully blended.

I usually spend about three to four minutes mixing. Do not rush this step. Thorough mixing helps the silicone cure properly.

After mixing, leave the silicone in the cup for approximately four to five minutes.

The exact waiting time depends on the silicone, its pot life, and the room temperature.

The goal is not to remove every single air bubble. This short waiting period simply allows the larger bubbles to rise to the surface before pouring.

Do not wait so long that the silicone begins to thicken. It should still be well within its working time when you begin filling the mold.

Pour the silicone into the mold in a thin, steady stream.

A slow pour gives the silicone time to flow into the fine tread details while allowing the remaining air to escape through the vent holes.

For this mold, filling it completely usually takes about six to eight minutes.

It is possible to pour faster, but I prefer taking my time because it helps produce a cleaner tire with fewer visible bubbles.

Watch the air vents while filling the mold. When silicone begins coming out of every vent, the mold should be completely full.

If one vent remains dry, there may still be an air pocket inside. Continue adding silicone slowly until silicone begins to overflow from every vent.

After filling the mold, leave the silicone to cure.

The manufacturer of my silicone recommends a shorter curing time, but I usually leave the mold for approximately ten hours or overnight.

Giving it a little extra time helps ensure that the tire is fully cured before it is removed from the mold.

Once the silicone has cured, remove the clamps or rubber bands.

The two mold halves may be held together tightly. I use a small flat screwdriver to gently begin separating them.

Apply a small amount of pressure at one tab, move to the next tab, and continue working gradually around the mold.

As the mold loosens, a larger gap will begin to form. Eventually, the upper half can be lifted off by hand.

Do not try to force the entire mold open from one location. Separate it gradually.

If you cast a hollow tire, remove the center mold sections from inside the tire.

If you cast a solid tire, carefully grab the edge of the tire and pull it out of the remaining mold half.

At this stage, the main casting process is complete, but the tire still requires a small amount of cleanup.

Remove the thin silicone flash along the mold seam with your fingers.

Next, use a sharp hobby knife or razor blade to cut out the center plug.

You do not need to apply much pressure. Use gentle back-and-forth movements and allow the blade to do the work.

Take your time and be careful while cutting.

Finally, use side cutters to remove the small silicone pieces created by the air vent holes.

The tire is now ready to be installed on the wheel.

The finished tires have a soft feel and a good amount of flexibility.

The tread lugs are clearly defined, and the silicone provides excellent traction. In my experience, these tires grip better than many standard RC tires, especially on rough terrain.

The same files also include a printable TPU tire for anyone who prefers to print the tire directly. However, for the best grip and the most realistic rubber feel, I recommend casting the tire in silicone.

You can see the complete mixing, pouring, demolding, and cleanup process in the full video:

Watch the full tutorial on RC Tire Lab

For available RC tire, wheel, and mold STL files, visit my Patreon page:

RC Tire Lab

Thanks for reading!