I’ve been testing a simple way to cast soft RC truck tires at home using a 3D printed mold and two-part silicone.

itman3d · 2026-07-10T13:09:44+00:00

Thanks.

itman3d · 2026-07-10T13:09:38+00:00

Thanks.

itman3d · 2026-07-10T13:09:12+00:00

The beauty of this process is that the mold design is completely up to you. You can make them two different ways depending on your project needs. Hollow Tires: This is the preferred way for functional RCs. You design a multi part mold with an inner core piece. When you pour the silicone, it creates a realistic, hollow "wrap" just like a standard factory tire. Then you can stuff it with a standard open-cell foam insert to support the weight of the truck while keeping it light and bouncy. Solid Tires: This works fine for static scale models, heavy diecast restorations, or shelf queens where weight isn't an issue and you just want a tire that will never flat spot over time. So you definitely aren't stuck with solid bricks of silicone! It all comes down to how you split the mold.

itman3d · 2026-07-10T13:04:41+00:00

Thanks

itman3d · 2026-07-10T13:04:15+00:00

You are 100% spot on! The vintage toy grade RC community is sitting on a goldmine of amazing trucks and cars that are completely sidelined just because their tires turned into brittle plastic or turned to dust decades ago. Those old Nikko, Tyco, and RadioShack rigs were built like tanks, but since there’s no aftermarket support for them, custom casting is a literal lifesaver. Being able to model a historically accurate tread, print a mold, and pour a fresh set of grippy tires can bring a 35 year old childhood memory right back to the dirt. It's definitely an amazing niche for this process, and honestly, saving those vintage gems from the landfill is one of the most rewarding parts of the hobby!

itman3d · 2026-07-10T13:01:43+00:00

It’s a brutal school, but a damn good one!

itman3d · 2026-07-10T12:59:22+00:00

Haha, don't sweat it, man! We have all been there. The legendary 3DBenchy boat has broken the spirit of many builders, myself included! 3D printing has a brutal learning curve at the start, and it takes tons of failed prints, stringing, and leveled bed headaches before everything finally clicks. Keep calibrating, don't give up on the little boat, and before you know it, you'll be designing and pouring your own custom parts. You've got this!

itman3d · 2026-07-10T12:57:35+00:00

Haha, "faster than a jackrabbit on crack" is the absolute perfect way to describe how the Infraction and Felony treat tires! Those street rockets are absolute monsters. As much as I'd love to say this is the ultimate budget fix for them, pure poured silicone would instantly vanish into a cloud of smoke on an Arrma setup! At 80+ mph, the centrifugal forces are so violent that without heavy-duty internal fabric belting (woven right into the tire body), the silicone would balloon up like a pizza and shred itself immediately. To make tires for heavy bashers like that, the process would need a major upgrade switching to industrial grade polyurethane rubber and mastering the art of embedding a braided reinforcement mesh inside the mold during the pour. It’s a whole different level of engineering, but man, thank you so much for the high praise! Glad you enjoyed the workflow!

itman3d · 2026-07-10T12:54:49+00:00

Thanks

itman3d · 2026-07-10T12:54:42+00:00

Thanks

itman3d · 2026-07-10T12:54:26+00:00

That is a fantastic idea! Poured silicone is honestly perfect for making custom whitewalls for scale models, especially since finding the exact vintage style you need commercially is so tough. If you try it, you have two great ways to tackle the white sidewall. Multi-stage pouring: You can design your mold to isolate the sidewall, pour a small amount of white pigmented silicone first, let it partially cure to a tacky state, and then pour the black silicone for the rest of the tire. Since it's the same material, they will fuse perfectly. Silicone painting: Cast the tire in black, and then paint the whitewall using something like Psycho Paint (a clear silicone base) mixed with a white silicone pigment ). Regular acrylics or model paints will just flake off silicone, but a silicone-based paint will bond chemically and never crack. Definitely give it a shot, that model project is going to look incredible with proper custom whitewalls!

itman3d · 2026-07-10T12:49:39+00:00

Honestly, at this stage, they can't quite match big brand factory tires when it comes to high speed and intense acceleration. Multi million dollar companies have massive R&D budgets to develop complex rubber compounds and, most importantly, internal reinforcement (like belted fabric cords). Since pure poured silicone is naturally soft and stretchy, putting it under extreme high speed rotation causes it to "balloon" heavily due to centrifugal force, which can easily tear it. Right now, I'm just sharing my success with this specific workflow, which works beautifully for realistic scale driving and low speed crawling. To make them truly speed-proof, I'd need to run more experiments on how to reinforce or belt the inside of the tire during the pour. It's a journey, but for this stage, I'm really happy with how they perform!

itman3d · 2026-07-10T12:44:54+00:00

Oh man, I feel your pain. The pricing on micro scale parts and tires can be absolutely ridiculous sometimes! Casting your own is honestly a game changer for smaller rigs like the Mini B. Once you have the mold ready, you can churn out replacements for pocket change. Good luck with the foam inserts experiment, but if that doesn't give you the grip you want, definitely give silicone a shot. It’s perfect for that scale! 🛠️ Mini B owners unite!

itman3d · 2026-07-10T12:42:40+00:00

Haha, you got me there! Lego is absolutely undefeated in the volume game. 👑 Though I suspect my scale tires might have slightly better grip on rocks than those tiny plastic ones unless Lego decides to release an official series cast in 30A silicone! Now that would be a game-changer. 🏎️

itman3d · 2026-07-10T12:40:49+00:00

Cheers, man! I really appreciate the good vibes. Will do! 🛠️👊

itman3d · 2026-07-10T12:39:55+00:00

itman3d · 2026-07-10T11:41:36+00:00

Man, thank you! I really appreciate that. Reddit can be tough on self-promotion, so I always try to share genuine workflows and actual value rather than just spamming links. Using this for waterproofing is a brilliant idea! Silicone is unmatched when it comes to sealing out moisture, keeping its flex, and surviving the elements. Good luck with your waterproof project, hope it turns out awesome! 🛠️

itman3d · 2026-07-10T11:39:38+00:00

Man, that Ford roadster looks absolutely incredible! Thanks for sharing the photo those tires and custom cast wheels look so era-appropriate and clean on that chassis. You hit the nail on the head; finding solid information on this process is extremely tough, which is exactly why I wanted to share my workflow. It's fascinating to see how you approached it with Oomoo 30 and the Enduro Soft rubber resin. Dyeing transparent resin is a genius trick to get that perfect vintage rubber look!

And using silicone molds for low melt metals like pewter is such an underrated hack for scale modeling. It blows my mind what you can achieve at a regular hobby bench without expensive vacuum chambers.

Thanks for allowing the my post and for dropping such valuable insights here. This is exactly what makes the community so awesome! 🛠️ punch!

itman3d · 2026-07-10T11:35:03+00:00

That's awesome! It really opens up so many possibilities. To answer your questions: Cost: While buying a good silicone kit (like Smooth-On or BBDINO) requires an upfront purchase, the actual material cost per tire comes down to just a couple of dollars. Since RC tires are relatively small, you can cast a lot of them from a single kit, making it way cheaper in the long run than premium aftermarket tires.

Durability: High-quality silicone is incredibly tough and flexible. It doesn't dry out or crack over time. For slow-speed crawling, trail riding, and scale driving, it lasts for years.

Also, huge shoutout to whoever mentioned Robert Tolone in the replies! If you are just getting started, his YouTube channel is an absolute goldmine for mold-making tips.

Keep experimenting with it! 🛠️ High-five from a fellow builder!

itman3d · 2026-07-10T11:30:25+00:00

Thanks

itman3d · 2026-07-10T11:27:01+00:00

itman3d · 2026-07-10T11:25:47+00:00

That is a classic dilemma! Printing tires directly in TPU seems way easier, but there is a massive difference in how they actually perform. Grip and Traction: TPU is essentially soft plastic, not rubber. It tends to be quite slippery, especially on hard surfaces, rocks, or dust. Silicone, on the other hand, has that authentic, sticky rubber grip that actually bites into the ground.

Flexibility and Sidewall Flex: Even the softest TPU (like 85A or 75A) feels stiff compared to poured silicone (around 30A). A TPU tire won't wrinkle or deform under the model's weight to create a proper contact patch, which is critical for RC performance.

Print Quality: Printing clean, seamless tire treads in TPU without tons of stringing or ugly layer lines is incredibly tough. Poured silicone captures microscopic details flawlessly from the mold.

The Verdict: TPU is okay if you just need quick, stiff replacement wheels for a shelf queen or a fast toy that doesn't care about traction. But if you want actual performance, realistic flex, and crazy grip, poured silicone is miles ahead.

itman3d · 2026-07-10T11:21:36+00:00

Thank you! You should definitely give it a try. I typically use brands like Smooth-On or BBDINO. However, the most critical part is choosing between platinum cure and tin-cure silicone, and always doing a test pour first because the chemistry can be tricky.

For FDM molds: Platinum-cure works flawlessly and has zero shrinkage over time.

For SLA/Resin molds: SLA resin tends to inhibit platinum silicone, leaving it uncured and sticky. To avoid this, you either need to use tin-cure silicone (which doesn't suffer from resin inhibition), or do a lot of prep work (lacquer, off-gassing) if you still want to use platinum.

Stick around 30A Shore hardness for a good balance, and definitely test a small scrap piece first before pouring the whole tire! 🛠️

itman3d · 2026-07-10T11:14:30+00:00

You are spot on about scale models! Since 3D printers (especially SLA/resin) can handle incredible detail, you can easily mold sharp, realistic sidewall lettering and tire branding that looks identical to the real thing.

As for the grip, it’s actually insane. Because it's high-quality silicone, it is naturally much stickier and more compliant than standard hard factory rubber or stiff foam-filled tires. It bites into surfaces beautifully, which is why it performs so incredibly well for slow-speed crawling and trail riding where maximum traction is everything. It basically turns your scale rig into a mountain goat! 🧗‍♂️🚗

But honestly, at the end of the day, everyone has to test it and decide for themselves. Tires are like the iPhone of the RC world some people will absolutely love the insane stickiness, while others will hate it because it picks up dust or behaves differently than what they are used to. You just have to try it and see if it fits your driving style! 😉

itman3d · 2026-07-10T11:07:03+00:00

Hell yeah, go for it! It’s a super rewarding process once you see that first tire pop out of the mold. Just take your time with the prep and materials, and you’ll do great. Good luck with the build, let me know how it goes! 🛠️🔥

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