Best Materials & Tools for Waterproofing Your RC Car

Water can be the bane of any RC (remote control) hobbyist. Whether you’re splashing through puddles, driving in the rain, or running your rig at the beach, protecting the electronics in your RC car is crucial. In this guide we’ll compare the top methods and materials used to keep RC cars dry – everything from sprays to seals – and explain when and how to use each one. We’ll also cover how to choose the right solution for your use (bashing, racing, beach runs), where to buy supplies, and important safety/disposal tips. Throughout, we’ll keep the language clear and easy (8th-grade reading level) and include handy comparison tables and links to tools you can find on Amazon (with affiliate tag rcblogs-20).

Quick Comparison Table

Below is a summary of the main waterproofing options for RC electronics. For each, we rate the skill required, permanence of the seal, serviceability (how easy it is to undo for repairs), and relative cost.

Each option has trade-offs. For example, spray-on products like CorrosionX are very easy to use (just spray inside a servo or on circuit boards) and easy to clean off, but they usually require regular reapplication. Conformal coatings (special electronic board coatings) take a bit more care to apply uniformly, but they form a durable moisture barrier scscoatings.com. Liquid tape and heat-shrink kits are also simple to use and cheap, making them great for beginners or quick fixes. Enclosures (sealed project boxes) offer the toughest protection (they physically block water) but can add bulk.

Tip: In an RC parts forum, one expert notes that none of the stock ESCs are truly waterproof; they recommend two easy fixes: “coat the entire board in liquid electrical tape” or dip it in CorrosionX, noting that CorrosionX “is basically a water dispersant and needs to be reapplied several times per year”. This illustrates that sprays/tapes are easy DIY fixes but are not one-time, permanent solutions.

Conformal Coating – A Protective Circuit Board “Varnish” 🛡️

What it is: Conformal coatings are thin polymer films (acrylic, silicone, polyurethane, etc.) designed to “conform” to the shape of a circuit board. You typically spray or brush them onto PCBs, fully covering components in a clear protective layer. Once cured, the coating shields the electronics from moisture, dust, and corrosion.

Why use it: These coatings act as a moisture barrier. Specialty coatings experts note that conformal coatings help achieve IPX4–IPX8 water-resistance ratings by sealing out condensation and rain. In fact, many high-end ESCs and receivers ship with factory-applied conformal coating so they can survive a bit of dampness. One user even mentioned that Castle Creations ESCs are already conformal-coated: “You can basically run the thing underwater already”. This shows how effective a proper coating can be.

How to apply: Shake well and either spray or brush the coating on a clean PCB. Make sure to cover all solder joints and chips, but avoid pooling. Work in a ventilated area. Let it dry/cure per instructions (often overnight).

Pros:

• Provides a strong, continuous moisture seal over entire circuit board.
• Doesn’t add much thickness, so airflow/cooling remains similar (unlike thick globs of sealant).
• Once dried, it stays flexible and doesn’t yellow (especially silicones).
• Castle ESCs and other quality components use it, so it’s a proven method.

Cons:

• Difficult to remove. Once hardened, you’ll need solvents or scraping to access the board for repairs. So serviceability is low.
• Requires a careful application (not as easy as spray-on grease). You should wear gloves and do it in a ventilated area because these chemicals can be harmful thermalspray.com.
• Dry time and safety precautions.

Skill Level: Moderate. Even a beginner can use spray conformal, but it helps to practice so you get an even coat.

Cost: Moderate. A decent aerosol conformal (e.g. MG Chemicals 419D) runs around $15–$25 for an aerosol can (affiliate example: MG Chemicals Acrylic Conformal Coating). A little goes a long way covering multiple boards.

Key Info: A well-known RC hobby site notes using both conformal coatings and epoxy for protection flitetest.com. After coating, Flite Test even recommends using epoxy to seal the ESC housing fully (because “hot glue will not work” long-term). In short, conformal coating is great for final-board protection if you don’t plan to modify the board often. It shields most of the board while still letting heat escape reasonably well (unlike a thick rubber dip which can trap heat).

CorrosionX & Other Anti-Corrosion Sprays 🌊

What it is: CorrosionX (by Corrosion Technologies) is a penetrating spray lubricant that also protects against water and rust. It’s an oil-based formula with “Polar Bonding™” technology that wicks moisture away and leaves an ultra-thin protective film on metal surfaces and connectors corrosionx.com. Other brands have similar products (e.g. WD-40 Specialist, CRC Dry Coat, Permatex Corrosion Blocker).

Why use it: These sprays are very easy to apply: just spray into the electronics and connectors. They provide lubrication plus a moisture barrier. The manufacturer claims CorrosionX actually “disrupts rust on the molecular level” and can be used on battery terminals, locks, and even electronics without harming circuits. Importantly, CorrosionX is dielectric – it won’t short out circuits. It literally “displaces moisture and seals it out with a self-healing high dielectric … coating”. In other words, you can spray it on wet electronics and it will shove the water out, leaving a thin protective coating.

How to apply: Shake the spray and apply a light mist to the circuit board or inside component housings. For servos or receivers, you might need to open the plastic case and spray directly on the PCB. Let it penetrate, then wipe excess (outside) so nothing gooey remains. You can even let your ESC sit fully wet in it and it will come out running (as shown in the Flite Test video). After spraying, be sure to let it dry before powering up.

Pros:

• Very easy to use (pour or spray on parts).
• Self-healing: the thin film can “flow” back into minor nicks in the coating, keeping protection continuous.
• Safe on electronics and has a very high dielectric strength (39,000+ volts), so it won’t conduct or interfere.
• Also lubricates moving parts (like servo gears) and keeps rust off metal gears/shafts.
• Works even on saltwater-exposed parts. The manufacturer specifically notes use in marine and coastal environments.

Cons:

• Temporary: It’s basically a light oil film, so needs reapplication. The Castle Creations ESC team says it should be reapplied “several times per year” if needed. In heavy-use RC, you might coat every few outings.
• Can attract dust/dirt if over-applied (it’s sticky when fresh). Wipe the excess off outside surfaces.
• Not a solid barrier like epoxy; it won’t stop a gush of water indefinitely.

Skill Level: Very easy. Spray or brush it on (some kits include brushes or small bottle applicators). Good for beginners.

Cost: Low to medium. A small bottle (4–6 oz) is ~$10. (Affiliate example: CorrosionX Spray).

Usage Tip: One RC forum user shared an official tip: “None of our controllers are waterproof… There are two methods that seem to work well: coat the entire board in liquid electrical tape, or dip it in CorrosionX.” He notes CorrosionX is “basically a water dispersant”. In practice, many hobbyists do both: use CorrosionX for its thin dielectric coat, and use liquid tape or shrink for connections. CorrosionX is especially handy for hard-to-reach nooks (spraying inside a servo or ESC housing).

Liquid Electrical Tape (Brush-On Rubber Sealant) 🖌️

What it is: Liquid electrical tape is a brush-on rubbery coating (usually made by 3M or Gardner Bender). It goes on like paint and dries to a flexible, waterproof rubber film. You get it in a jar with a brush in the lid.

Why use it: It’s perfect for sealing connectors, wire splices, and small boards. For example, after soldering a bullet connector, you can brush liquid tape over the exposed solder, let it dry, and you’ve created a water-tight seal. It’s far easier than wrapping with tape in tight spots. The dried coating stays flexible, UV-resistant, and protects against corrosion. It is truly waterproof once cured.

How to apply: Just shake the bottle, then brush the liquid onto the area you want to seal. Work in thin coats (10 minutes dry time each coat); two coats is often enough. Typical dry time is 24 hours. It’s best applied at room temperature and in a well-ventilated area. The finish is usually black or transparent red.

Pros:

• Very easy application: Even a beginner can brush it on.
• Peel-able: Unlike epoxy, dried liquid tape can be cut or peeled off if you need to reopen a joint (for repair or warranty).
• Flexible and durable: It won’t harden or crack in cold or heat (–30°F to +200°F).
• Resists chemicals and salt: According to the manufacturer, it resists solvents, saltwater, and UV – ideal for outdoor use.
• In a pinch, you can brush it inside a servo or on small boards, though it’s usually used for exposed wiring and terminals.

Cons:

• Only covers smaller areas (brush size). It’s not practical for coating large PCBs.
• Dries slower (24 h for full cure).
• Fumes are toxic – do it outside or in a fume hood! (It has solvents similar to paint.)

Skill Level: Easy. Just brush it on like paint. It’s hard to mess up.

Cost: Low. A 4 oz jar runs about $7–$10 (e.g. Gardner Bender Liquid Tape).

Example: Gardner Bender’s specs say the liquid tape forms “a protective, waterproof, UV-resistant, dielectric seal” around spliced wires and “will not unravel or deteriorate like traditional tape” in extreme weather. It’s widely used by electricians and now by RC hobbyists. As one forum user put it, he used liquid tape plus heat-shrink on his battery bullet connectors and “been through rain, snow, sleet and they’ve been fine.” Just remember: it stinks while drying and may need mask/ventilation.

Heat-Shrink Tubing (Adhesive-Lined Tubing) 🔥

What it is: Heat-shrink tubing is a hollow plastic tube that shrinks when heated. Waterproof (dual-wall) heat-shrink has an inner layer of glue or hot-melt adhesive. When you heat it, the tube shrinks and the glue melts, creating a fully sealed, waterproof sleeve over the wire or connector.

Why use it: It’s ideal for sealing wire joints and connectors. It’s especially handy after soldering: slide the right size tubing over the solder joint, then heat it (with a heat gun or lighter) and it forms a tight, sealed cover. Kits come with many sizes. The dual-wall type with inner glue is common in automotive or marine kits.

How to apply: Choose tubing slightly larger than your wire bundle/joint. Cut to length, slide over the area, and apply heat evenly (e.g. from a heat gun, hair dryer, or even a lighter in a pinch). The tubing will shrink (often 3:1 or 4:1 shrink ratio) and the glue lining will flow, sealing any gaps cabletiesandmore.com.

Pros:

• Waterproof seal: As one retailer explains, the heat activates the inner glue, “which forms a tight bond with the wires and creates a moisture-resistant seal”.
• Very durable and abrasion-resistant once shrunk.
• Easy to use with practice; no messy oils.
• Removable: if you need to redo a joint, just cut through the tubing (then replace it).
• Very cheap. Many kits (200+ pieces) cost under $10.

Cons:

• Only works on linear joints (wires, not whole boards).
• Requires a heat source (so take care not to overheat nearby parts or melt plastic bodies).
• Some cheap tubing shrinks less; better to buy kits that specify marine/adhesive-lined.

Skill Level: Easy. Even kids have done this as a craft. Just be careful with the heat source (and don’t burn yourself or wires).

Cost: Very low. Bulk kits with dozens of sizes are usually $10 or less (e.g. MILAPEAK Heat-Shrink Kit with 270 pieces).

Waterproof Enclosures (Sealed Project Boxes) 📦

What it is: A waterproof enclosure is simply a plastic or metal box (often IP65–IP67 rated) designed to be water-tight. RC hobbyists use them to house receivers, ESCs, or batteries. The box typically has a rubber gasket, and cable glands (sealed holes) for wires.

Why use it: This is the most foolproof way to keep electronics dry: the entire circuit sits inside a waterproof case. If done right, you can even submerge the box briefly without water getting in. It’s like giving your electronics a diving suit.

How to apply: Mount your electronics inside the box. Seal all cable entries: either use pre-sealed glands or fill gaps with silicone (and use shrink tubing on the wires before they enter). Make sure the lid is closed securely with its gasket. Often hobby-grade enclosures are small and light (e.g. 5×4×3 inch boxes).

Pros:

• Very robust: Blocks water from even reaching the components.
• Still serviceable: you can open the box to work on electronics (unlike epoxy potting).
• Once installed, no need to reapply coatings – it’s a one-time setup.

Cons:

• Bulk: adds size/weight and can make airflow minimal (so heat can build up if not vented).
• You must carefully seal all openings (or it defeats the purpose).
• Some enclosures are expensive ($10–$20+).

Skill Level: Easy to moderate. Basic assembly skills – mounting screws, silicone sealant – are needed.

Cost: Moderate. Simple ABS junction boxes (IP65) run $10–$15. For example, Zulkit IP65 waterproof junction boxes are popular. A hobbyist can use one like this Zulkit ABS Project Box to store a receiver or ESC.

Example Use: If you’re tackling extreme conditions (rock crawling through streams, or a high-end rock racer), putting your receiver or BEC inside a sealed case is common. Many scale rock crawlers come with sealed receiver boxes. In fact, one Redditor joked that sand and saltwater are the “world’s worst” for RC cars, and recommended a 3D-printed o-ring sealed body to keep stuff out – essentially making the whole electronics compartment a waterproof enclosure.

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How to Choose by Use-Case ⚙️

Different RC activities demand different protection levels. Here’s how to pick materials for your use-case, plus some warnings:

• Bashing (mud/rain/street): You’ll hit puddles, mud, maybe even shallow water. Recommended: Use a combination of methods. For full-board protection, conformal coat your ESC/receiver and use epoxy or silicone potting on sensitive areas (if you won’t need to open them). Use liquid tape or heat-shrink on all bullet connectors and extension plugs (battery, motor, servo leads). Consider housing gearboxes or servos in their own sealed covers. Always spray CorrosionX or similar onto metal parts and gears after use. Warning: Even if coated, avoid deep water (where salt or dirt is heavy) and always clean after. In a bashing crash, water can jet inside gaps, so it’s not 100% foolproof. After every muddy run, rinse everything with fresh water and dry it – especially metal parts and unsealed connectors – and reapply lubrication or sealant as needed. Salt or mineral-rich water is especially bad (see Beach Runs below).
• Racing (on-road/track): Usually less contact with standing water, but you might still race in light rain or a dewy morning. Recommended: Conformal coat the ESC and receiver boards for basic splash protection (IPX4 level). Use liquid tape on any exposed wire splices or connectors. Heat-shrink any soldered joints you won’t see often. These will handle occasional spray. If racing on wet tracks regularly, take spare coatings and plan for re-spraying CorrosionX every few races. Warning: Racing electronics (ESCs, LiPo batteries) often generate a lot of heat. Avoid thick coatings or potting on anything that needs cooling (the motor wires and ESC’s MOSFETs should breathe). Conformal coatings are OK, but do not fully encase a running motor in silicone/epoxy – it can melt or overheat the windings. Also, keep foam/coverings off of antennas and receivers when it’s wet outside, as damp can get inside the fabric.
• Beach Runs (sand/saltwater): Saltwater is notoriously corrosive. Sand is abrasive. Recommended: If you’re running right on the water, the best plan is an IP-rated marine-style build: fully sealed motor compartments (like water-cooled brushless motors in RC boats), sealed servo boxes, etc. Use the heaviest waterproofing: epoxy-potting (for non-serviceable use), plus sealed enclosures for electronics. After any exposure to salt air or spray, flush with fresh water immediately and dry thoroughly. Apply a corrosion inhibitor (like CorrosionX) after cleaning. Re-oil or grease all metal joints with marine grease. If possible, replace metal screws/shafts with stainless. Warning: Even “waterproof” parts can fail in salt. The salt can wick through small gaps and create a short. One forum user noted that people worry about salt – and they should: “taking their RC cars near salt water… salt and sand are the world’s worst on RC toys.” The best tactic is maintenance: always clean and lubricate after. Never assume a cheaply-coated ESC will survive dunking in salt. If you must drive on the beach, rinse the vehicle before turning it on again.
• General Tips: Always protect connectors. Use dielectric grease or CorrosionX on bullet connectors and servo plugs if they stay exposed. Marine-grade products (copper grease, anti-corrosion sprays) are cheap insurance. And remember: any protective coating is only as good as its weakest point. A single uncapped servo port or wiring hole can leak.

In summary, for casual running in light rain or puddles, coatings and tapes may suffice. For hardcore bashing or beach use, go overboard: potting, enclosures, and meticulous cleaning. Even then, expect to do regular maintenance – there’s no permanent fix for constant dunking.

Where to Buy and What to Avoid 🛒

Where to Buy: Most of these materials are readily available online or in stores. Electronics suppliers (like Mouser, Adafruit, Sparkfun) carry conformal sprays and solder-seal kits. Hobby shops and Amazon sell RC-specific products (many affiliate-linked examples below). Stores like Home Depot or auto parts shops might carry general versions (Permatex Liquid Tape, Seachoice heat-shrink, etc.). When buying, look for reputable brands: MG Chemicals, Techspray, Gardner Bender, CorrosionX, 3M, etc.

• Amazon Examples (with affiliate tag rcblogs-20):
  • MG Chemicals Acrylic Conformal Coating – a clear aerosol spray used by many hobbyists.
  • CorrosionX Lubricant Spray – the small precision-tip bottle (4 fl oz) for RC electronics.
  • Gardner Bender Liquid Electrical Tape – 4 oz jar of black brush-on insulating liquid.
  • Adhesive-Lined Heat-Shrink Tubing Kit – e.g. MILAPEAK 270pc 3:1 shrink kit.
  • Zulkit Waterproof Project Box (ABS, IP65) – a sealed enclosure for a receiver or small ESC.

What to Avoid: Be cautious of cheap knock-offs or vague “waterproof” claims. Some generic sprays (off-brand rust inhibitors) may not be safe on electronics or might not form a true dielectric layer. Avoid any product not labeled for electronics or moisture-blocking. Never use silicone caulk or glues not rated for electronics (they can off-gas corrosive acids or trap heat). Also avoid “short-term fixes” like dipping boards in common oils or waxes – they don’t form a lasting seal.

Ventilation Warning: Many waterproofing products release hazardous fumes! Whether conformal spray or liquid tape, always use them outdoors or in a well-ventilated area. Wear gloves and eye protection. One conformal-coating guide stresses that operators should use respirators and fume extraction because the chemicals “may be harmful if inhaled or absorbed”. In other words, don’t spray inside a closed room, and do not lick your fingers afterward.

Safety and Disposal Tips ⚠️

• Use Protective Gear: Gloves, safety glasses, and a mask are strongly recommended when handling sealants, sprays, and solvents. Many chemicals used in coatings can irritate skin or lungs. Thermal spray experts advise this PPE for conformal coatings, and the same applies to hobby products.
• Ensure Ventilation: Set up a fan or work near a window. Fumes from liquid tape or glue can be very strong (one user warned liquid tape “stinks and gives you a hell of a buzz” if used in a closed space).
• Avoid Heat Sources: Keep flammable aerosols and paints away from open flames. Many conformal sprays and lubricants are flammable. Let the coating dry fully before testing electronics, and keep away from hot soldering irons during application.
• Proper Disposal: Never pour leftover chemicals down the drain or trash them with regular garbage. Follow disposal rules for hazardous waste. For example, a conformal coating Safety Data Sheet specifies to “dispose of waste and residues in accordance with local authority requirements,” and not to burn the empty can (explosion risk) farnell.com. In practice, let small amounts of leftover solvent evaporate in a safe, ventilated area (away from fire), and bring rags/containers to a hazardous-waste drop-off if your community has one.
• Clean-Up and Storage: Clean brushes/tools with isopropyl alcohol or the recommended solvent and store products in a cool, dry place. Label any homemade mixtures. Don’t leave boards soaking in chemicals – apply only what you need.

Remember: these chemicals work great when handled safely. Taking precautions (ventilation, protective gear) ensures you stay healthy and have no accidents. By following instructions and local guidelines, you’ll protect not just your RC but yourself and the environment.

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Sources: Waterproofing methods and advice are compiled from RC hobby forums, technical articles, and product data sheets. For example, a FliteTest article demonstrates using CorrosionX and epoxy for water protection, and the Specialty Coating Systems blog explains how conformal coatings form a “critical moisture barrier”. Castle Creations and other RC experts have noted that using liquid tape or CorrosionX can make non-waterproof ESCs more resilient. Manufacturer datasheets (e.g. Gardner Bender and CorrosionX) describe the waterproof properties of these products. We also reference safety guidelines for coatings and disposal recommendations from material safety data sheets to ensure complete guidance. These citations back up the tips and comparisons above.