Ultimate Guide to Waterproofing Your RC Car

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Table of Contents

  • Why Waterproofing Matters
  • Types of Waterproofing
  • Quick Decision Checklist
  • Overview of Methods
  • When NOT to Attempt Waterproofing
  • How to Plan Your Waterproof Project
  • Resources & Recommended Reads
  • Quick FAQ

Why Waterproofing Matters

RC cars are fun in the rain, mud, or snow, but electronics and water are a bad mix. Even models that boast “waterproof” components are not meant to be driven underwater. As one RC guide warns, RC cars should “never go… underwater” – their waterproof electronics can handle splashes and quick puddles, but full submersion will damage them. Learn more from AMain Hobbies.

All of the metal parts in your car (screws, pins, axles, etc.) can rust and seize if left wet. Even water getting into the tire vent holes causes muddy foam inserts to rot. In short, driving through deep water or failing to dry out your car can cause short circuits and corrosion that ruin parts. 🔧

Allowing your RC to sit wet or dirty only makes things worse. Dirt and grime hold moisture against bearings and shafts, speeding up rust. Experts say it’s fine to get a waterproof RC a little wet only if you clean and dry it afterward. Remove the tires, peel back any tape on vents, and blow out or wipe down every nook. If you don’t, rust spots can eat away at metal components (as the photo above shows) and lead to expensive failures. 💧

Finally, remember that any aftermarket waterproofing you apply may void the manufacturer’s warranty. In fact, a hobby guide bluntly states that treating electronics to keep out water “voids the warranty of every product it is used on”. Many RC enthusiasts accept this trade-off, but it’s a downside to DIY coatings or potting. Before you start sealing things, be aware that you’re likely giving up the warranty. ⚠️

Types of Waterproofing

Broadly speaking, there are temporary and permanent waterproofing methods.

  • Temporary methods are quick fixes or covers that you can remove whenever needed. These include using latex balloons, zip-top bags, or silicone tape to wrap electronics each time you drive. For example, one racer wrote that in wet races he’d cover the receiver and ESC in deflated balloons sealed with heat-shrink tubing, which is “easily reversible for any required servicing”. Check Reddit’s RC Cars community. Spray-on products like liquid tape or general silicone also count as semi-temporary coatings. The plus side is easy maintenance; the downside is you must redo the wrap for each run, and they aren’t 100% foolproof. 🛡️
  • Permanent methods involve long-lasting coatings or sealed enclosures. These include conformal coatings (silicone, acrylic, or urethane paints for PCBs), epoxy potting, or installing dedicated waterproof servos/ESCs. For example, hobby stores sell silicone conformal coatings that you brush onto circuit boards. CowRC’s “Industrial Grade Thick Silicone Conformal Coating” can treat several ESCs at once – a single 10ml bottle covers 3–5 electronics boards in one thick coat. Explore CowRC products. Once dry, it forms a durable barrier. The trade-off is that these coatings dry into a permanent seal: you often must scrape or reapply them to access the electronics again. But well-applied, they can protect sensitive components from moisture more reliably than plastic wraps. 🔒

Both approaches have their place. Temporary covers are cheap and quick; permanent coatings are messier but give fuller protection. Later sections will explain specific techniques for each. 🌟

Quick Decision Checklist

Before you dive into waterproofing, ask yourself a few questions:

  • Is my car already somewhat waterproof? Check your manual or specs. Many hobby vehicles have water-resistant parts but few are fully waterproof. For instance, a Losi model is sold as a “water-resistant vehicle with waterproof electronics”, meaning its ESC, receiver, and servos have protection, but “most of the mechanical components are water-resistant and should not be submerged”. View Losi manual. In practice, assume your RC can handle splashes, mud, and light rain, but not deep water or full submersion. 📋
  • Which parts need extra protection? Electronics like the ESC (speed controller), receiver, and servo motors are top priorities—they often have exposed circuit boards. Even if your motor is brushless and sealed, any exposed metal gears or sensors can corrode. Also protect wires and connectors: the battery leads, motor wires, and switch bullets can short if water pools. Tape up or heat-shrink any exposed plugs. Don’t forget smaller items: oil-filled shocks or bearings can also rust from dirt. ⚡
  • Battery care: Most rechargeable batteries (LiPo packs) aren’t sealed. If water bridges the metal terminals, it can short them. Apply a thin film of dielectric grease on metal contacts (battery, motor, steering linkages) to repel water. A product like Silicone Dielectric Grease (8oz) can be used on bullet connectors and battery terminals to seal out moisture. 🔋
  • Check tire vents: Many wheels have vent holes. Cover these with tape or plugs so water doesn’t soak the foam inserts. Even tires can spin out water at speed, but vents let mud in. 🛞
  • Plan for maintenance: Consider how often you’ll need to open things up. If you like to service your ESC or motor frequently, prefer reversible methods (like balloons or bottles) over permanent potting. Remember, some waterproofing (spray or conformal) is one-way: you might have to sacrifice the seal to repair the electronics. 🧰

Use these points to decide whether you need more protection and which method suits your style. If the car is already quite water-ready, small steps (like zip ties or grease) may suffice. If it’s not, a full waterproofing project might be worth the effort. ✅

Overview of Methods

There are several ways to keep an RC’s electronics dry. Each method has its pros and cons, and often the best solution is to use multiple techniques together. Here’s an overview of common methods:

  • Balloon & heat-shrink enclosure: A classic DIY trick is to use a latex balloon as a cover. Cut or puncture a hole for the wires, slip the deflated balloon around the ESC or receiver, and seal the opening with heat-shrink tubing that you shrink around the wire leads. This creates a waterproof “bag” that can be slipped on and off as needed. It’s very cheap (just balloons and heat-shrink) and completely reversible, making maintenance easy. The image above shows one hobbyist test: even a wrapped ESC survived brief submersion. The downside is balloons can tear and they trap heat, so limit run times and inspect frequently. 🎈
  • Conformal (or silicone) coatings: These are special waterproof paints or pastes for circuit boards. You brush or spray them onto boards and wires to form a thin protective layer. For example, ElectroniCoat Conformal Coating Spray is a commercial spray that claims to build “an impenetrable barrier against moisture… even when fully submerged”. Get it on Amazon. Brands like CowRC sell silicone conformal solutions (e.g., their 10ml Cow-Formal coating) that harden on PCB traces. Conformal coatings are relatively permanent: once dry, they’re hard to remove. They are applied in layers (often 2–3 coats) and need hours or overnight to cure. The advantage is thorough coverage; the downside is you need good ventilation (they smell) and you can’t easily open the electronics again. 🖌️
  • Silicone or epoxy potting: This takes coatings a step further. Some racers even pour clear silicone “potting” compounds or epoxy over entire boards. The mixture flows around components and cures solid, sealing everything. It’s very waterproof (even dustproof), but it’s permanent. You won’t be able to remove or repair those parts easily later. It’s a heavy-duty method, best if you’re sure the setup is final. 🛡️
  • Waterproof electronics from manufacturers: Some RC parts are made to be water-resistant. For example, many servos from Spektrum (and some from other brands) are sold as “waterproof” – they have internal seals around gears. Traxxas cars come with a waterproof servo case and receiver box. If your ESC/receiver is labeled waterproof (often meaning splash-proof with sealed gaskets), that’s a big help. Still, these usually guard against drizzle and splashes, not full submersion. Often companies use silicone-covered electronics or coated PCBs (effectively pre-done conformal coatings). 🏭
  • Enclosures and boxes: If there’s space, you can build a hard shell around components. Small project boxes or 3D-printed covers can be used to hold electronics. Seal them with silicone gaskets or O-rings. For example, RC bug build threads sometimes show modelers using Pelican-style cases or custom enclosures for receivers. 📦
  • Heat-shrink and silicone tape: For wire junctions and connectors, wrap them in multiple layers of electrical tape or self-fusing silicone tape. This is not foolproof, but it repels water. You can even use liquid tape (a rubberized paint) around solder joints or connector backs for extra seal. These are semi-permanent and harder to remove. Try a Heat Shrink Kit on Amazon. 🔗
  • O-rings and grease: On some parts you might install rubber O-rings. For example, covering the gap around a servo output shaft with a tiny O-ring can slow water entry. Similarly, you can apply a tiny dab of waterproof grease on bearings or threads to keep water out. 🛢️

In practice, a combination of the above works best. For example, you might conformally coat the receiver board for a permanent layer, then still wrap it in a balloon or ziplock as a backup. One RC hobbyist summed it up: cover the main metal parts with a corrosion-inhibiting spray, seal the rest with heavy-duty silicone, and you have dual protection. See RC Parts guide. 🌈

When NOT to Attempt Waterproofing

Warning: Some situations are simply too extreme for DIY waterproofing. Avoid these at all costs:

  • Deep submersion: Even a waterproofed car is not a submarine. Never drive fully underwater or go past your wheels. The pressure and volume of water will eventually find a way in. The electronics can short or flood in seconds. As one manufacturer notes, their vehicles are built for creeks and puddles, but “should NOT be treated like a submarine”. In other words, if the water level will cover any part of the chassis, don’t go there. 🚫
  • Salt water or chemically treated water: Salt water is deadly to electronics. Saltwater is “very conductive and highly corrosive,” and most manuals explicitly forbid any saltwater contact. Ocean beaches, salted roads, or even chlorinated pools can quickly eat through metal and ruin circuits. Even if you rinse an RC in fresh water afterwards, the salt can leave behind deposits that corrode. Never run your RC in saltwater; if you want amphibious fun, there are specially-built water boats for that. 🌊
  • Rapidly moving or unknown water: If you can’t see underwater obstacles, you might break or flip the car. Also, if the water is muddy, contaminated, or unknown (like sewers or storm drains), avoid it. Chemicals, oils, or fine silt can damage moving parts quickly. ⚠️
  • Sub-freezing conditions: Extreme cold isn’t usually about water ingress, but frozen electronics can crack or fail. And if water does enter before freezing, it expands and breaks parts. Use caution in ice or snow (better to let the car thaw and dry fully). ❄️

In short, stay shallow, fresh, and relatively clean. Even when you follow all waterproofing steps, deep water and salt remain off-limits. The best rule is: don’t risk it. If you wouldn’t strap a waterproof speaker to go on a submarine mission, don’t treat your RC that way either. 🛑

How to Plan Your Waterproof Project

Before diving in, set yourself up for success with a plan:

  • Gather tools and supplies: You’ll likely need things like a heat gun (for heat-shrink tubing), silicone brushes or spray applicators (for coatings), plastic bags or balloons, zip-ties, silicone tape, and cleaning materials (brushes, compressed air). For permanent sealing, have conformal coating or electronic silicone on hand. For example, a small bottle of Clear Electronic Silicone Adhesive (electronics-grade RTV silicone) lets you seal gaps and screw holes. Keep some isopropyl alcohol for cleaning boards before coating, and cotton swabs for precise application. Don’t forget basic tools: screwdrivers, pliers, and wrenches to open the car easily. 🛠️
  • Estimate time and cost: Waterproofing isn’t a five-minute task. Coating an ESC and receiver can take hours (including drying time) and may run you $10–$30 in materials. For example, a can of conformal spray or silicone coating is usually $15–$40, while a heat-shrink tubing kit (like the 450pc Heat Shrink Kit) is under $15. Latex balloons and zip-lock bags are nearly free. Allocate an afternoon or evening per component: you may apply a coat, wait a few hours to dry, then apply another coat. Plan to do it in a well-ventilated area (solvents smell!). Budget a couple of weekends if you want to coat motors and lights too. ⏰
  • Consider serviceability: Think about maintenance cycles. If you often replace gears or the ESC, you might prefer reversible methods. Wrapping electronics in balloons or bags is undoable, whereas conformal-coated boards require scraping to fix. Also plan for future upgrades: if a coating makes disassembly really hard, you might forget it’s there and break something. Some pilots coat lightly for moisture resistance, others fully immerse (pot) the device. 🔄
  • Prepare for testing: Set up a safe test environment first. Some hobbyists fill a shallow tub with water to see if the car survives a quick dunk. It’s better to test before you actually go racing in wet conditions. Wear safety glasses (coatings can spray), and let the car dry completely before the next step. 🧪
  • Service and maintenance: Waterproofing is not “set it and forget it.” After each wet run, you must clean and dry the car thoroughly. Have towels, compressed air, and brush-on rust inhibitor (like a water-displacing oil) ready. Plan to reapply tapes and grease regularly. This ongoing care is just as important as the initial waterproofing work. 🔄

Overall, treat this project like a home-improvement task: gather the right gear, give yourself enough time, and think ahead about repairs. A well-planned job will last longer and work more reliably. 🎯

Resources & Recommended Reads

  • CorrosionX article (RCParts): A detailed guide on using CorrosionX spray to protect RC electronics. (Explains how a thin film can prevent water contact.) Read on RC Parts.
  • Losi Polaris RZR Pro R Manual: The manufacturer’s chapter on wet-weather operation. It clearly states which parts are waterproof and how to care for the vehicle after wet runs.
  • r/RCCars threads: Enthusiast discussions on waterproofing techniques. Notably, the “Waterproof this receiver” thread shows the classic balloon method in action and mentions products like CowRC’s conformal coating. Browsing hobby forums (RCCarAction, RCUniverse, etc.) reveals many tips from racers.
  • CowRC Silicone Conformal Coating (product page): Read about the “Cow-Formal Silicone” coating used by hobbyists. It gives an idea of how one professional product is applied (brush it on both sides of a board and let it cure).
  • RC maintenance articles: For general advice, see guides like “Seven Ways You Are Destroying Your RC Car” from AMain Hobbies, which includes a section on driving underwater and leaving cars wet. These highlight common pitfalls and care tips.
  • Amazon product examples: For gear to buy: ElectroniCoat Conformal Coating Spray (military-grade waterproofing), Clear Electronics Silicone Adhesive for sealing gaps, Silicone Dielectric Grease (8oz) to coat connectors, and a 450pc Heat Shrink Tubing Kit for insulating wires. These can serve as practical tools for your project. 🛒

Quick FAQ

  • Can I drive my RC car in the rain? Yes – if it’s designated waterproof/resistant and you protect the electronics. Factory-assembled waterproof RCs are meant to handle rain and splashes. One manual notes their vehicle is okay in “puddles, creeks… and even rain”. However, after any wet run, clean and dry the car thoroughly. As experts say, a waterproof RC can get wet “but only if you clean and dry it afterward”. This prevents rust and keeps it running smoothly. ☔
  • Will adding a coating or seal void my warranty? Almost certainly. Manufacturers generally don’t warranty water damage or user modifications. In fact, an RC parts guide flatly admits that any such treatment “voids the warranty”. Even ignoring that, if you open parts and paint over sensors, you’re outside the original specs. So be prepared: DIY waterproofing is at your own risk. 📜
  • What about using it in salt water or deep puddles? No. Salt water is explicitly off-limits. Salt water “is very conductive and highly corrosive,” and can destroy both electronics and metal parts. Likewise, don’t wade through water higher than the chassis. If a motor gets too wet, its life will shrink rapidly. In short, fresh rain puddles are one thing; oceans or deep streams are another. 🚫

By following these guidelines and picking the right methods, you can enjoy your RC car in wet conditions while minimizing damage. Always remember to maintain your vehicle – a little care goes a long way in extending its life. Have fun, but stay dry! 🚗💨