Which Magnet Coating Is Best for Outdoor or Wet Environments?
For anything submerged, salty or constantly wet, a sealed plastic coated magnet is best. For outdoor and humid use where you need full pull force, choose an epoxy coated magnet. Our plastic coated magnets are zinc-plated magnets sealed in an ABS shell about 1 mm thick, so they’re fully waterproof but pull less. Epoxy coated magnets add a thin black epoxy layer over the standard nickel plating and keep the same pull force as the uncoated version. Rubber coated magnets suit painted outdoor surfaces but shouldn’t be submerged, and standard nickel plating is for dry, indoor use.
- Submerged or salt water
- Plastic coated
- Rain, humidity, outdoors
- Epoxy coated, full pull force
- Painted or finished surfaces
- Rubber coated
- Dry and indoors
- Standard nickel (Ni-Cu-Ni)
Why Do Neodymium Magnets Need a Coating Outdoors?
Neodymium magnets are about two-thirds iron, so the bare alloy rusts quickly. The standard nickel-copper-nickel plating seals it well in dry air, but rain, humidity, condensation and especially salt eventually find their way through any scratch, chip or thin spot, and the magnet starts to corrode from that point. Water doesn’t weaken a magnet’s field; corrosion does, by eating away the magnet. See will neodymium magnets rust?
Which Coating for Which Environment?
| Environment | Best choice | Avoid |
|---|---|---|
| Dry, indoors | Nickel (Ni-Cu-Ni), or any coating | — |
| Humid rooms, bathrooms, basements | Epoxy, or plastic for the most protection | Bare nickel long term |
| Outdoors in rain, dew and humidity | Epoxy for full pull force, or plastic for the most protection | Bare nickel |
| Submerged in fresh water | Plastic; epoxy if it stays unscratched | Nickel, rubber |
| Salt water, sea spray, coastal air | Plastic | Nickel, rubber; epoxy is only fair |
| Washing machines and laundry | PVC sewing magnets | Everything else |
| Painted surfaces outdoors, such as vehicles | Rubber coated | Bare magnets, which scratch paint |
| Food processing and washdown | 316 stainless steel housings | Plated magnets |
How the Coatings Compare
| Coating | Water protection | Effect on pull force |
|---|---|---|
| Nickel (Ni-Cu-Ni), our standard plating | Dry, indoor use | None: it’s how magnets are rated |
| Epoxy over Ni-Cu-Ni | Good for humidity, rain and outdoor use | None: same listed pull force |
| Plastic (ABS) shell over zinc plating | Waterproof; best for salt water | Large: the shell is a 1 mm gap |
| Rubber, often over a pot magnet | Fair; not for submersion | Some, but better grip on walls |
| PVC sewing magnets | Survives washing | Some |
| 316 stainless housing | Excellent, including washdown | Depends on the design |
Specialty coatings such as electroless nickel, parylene, PTFE and Everlube are available on custom orders; see all coating options.
Plastic Coated: Best Protection, Lower Pull Force
A sealed plastic shell is the most reliable protection against water and salt, and it also guards the brittle magnet against chips. The trade-off is that the shell holds the magnet about 1 mm away from the steel, which acts as an air gap:
So when you switch to plastic coated magnets, size up. A plastic coated magnet holds about a quarter to a third of the rating of the same uncoated size. See how air gaps affect magnet strength. Shop Plastic Coated Magnets.
Epoxy Coated: Full Strength for Outdoor and Humid Use
Epoxy is thin, so it doesn’t measurably change the pull force: our 3/4 × 1/4 Inch N52 disc is rated 23.7 lb in both nickel and epoxy. It adds a tough, sealed barrier over the plating that holds up well to humidity, rain and outdoor use. Its weak point is scratches: epoxy is softer than metal plating, so avoid sliding it across steel or letting magnets snap together, and replace a magnet if the coating is chipped through. Shop Epoxy Coated Magnets.
Rubber Coated: Grip and Paint Protection
Rubber coated magnets, like our rubber pot magnets and hooks, are made for mounting on painted or finished surfaces such as vehicles, steel doors and equipment. The rubber protects the paint and grips much better than bare metal on vertical surfaces, and it covers the steel cup that would otherwise rust outdoors. Rubber isn’t a waterproof seal for long-term submersion, so keep these out of standing water. Shop Rubber Coated Magnets.
Tips for Magnets Outdoors and in Wet Places
Protect the Coating
Most corrosion starts at a chip or scratch. Let magnets come together gently, use spacers, and don’t drill or cut coated magnets.
Rinse After Salt
After salt water or road salt, rinse magnets in fresh water and dry them. That goes double for nickel plated Fishing Magnets.
Watch the Steel Too
The steel surface can rust as well, and rust under a magnet adds a gap. Rubber coated magnets and painted or galvanized steel help.
Mind the Sun
Dark surfaces in summer sun get hot. Standard grades are rated to about 80 °C (176 °F); see magnet temperature limits.
Seal Plated Magnets
For occasional moisture, seal a plated magnet’s edges with clear epoxy or lacquer, or set it in a pocket sealed with epoxy.
Use Stainless Hardware
Stainless steel screws won’t rust or stain around a countersunk or pot magnet.
Which Magnet for Common Outdoor and Wet Uses?
| Use | Our recommendation |
|---|---|
| Signs, banners and decorations on outdoor steel | Epoxy Coated or Plastic Coated magnets |
| Vehicle signs, lights and equipment on painted metal | Rubber Coated Pot Magnets |
| Boats, docks and beach use | Plastic Coated magnets |
| Aquariums | Plastic or epoxy coated; see aquarium magnets |
| Clothing, curtains and washable fabric | PVC Sewing Magnets |
| Garages, sheds and humid basements | Epoxy Coated magnets |
| Food plants and washdown areas | 316 Stainless Grate Magnets |
Takeaway
Choose plastic coated magnets for submersion, salt and constant wetness, and size up to make up for the shell. Choose epoxy coated magnets for outdoor and humid use when you need the full pull force of a standard magnet. Use rubber coated magnets on painted surfaces, PVC sewing magnets for anything that gets washed, and keep standard nickel plated magnets dry and indoors. Not sure? Tell our team where the magnet will go, and we’ll recommend a coating.
- Plastic Coated MagnetsWaterproof Shell
- Epoxy Coated MagnetsBetter Moisture Resistance
- Rubber Coated MagnetsScratch-Free Grip
More Questions About Magnets and Water
Are neodymium magnets waterproof?
Standard nickel plated magnets aren’t; plastic, epoxy and PVC encased magnets are made for wet use. See are neodymium magnets waterproof?
Will neodymium magnets rust?
Yes, if moisture gets through the plating, especially with salt or scratches. See will neodymium magnets rust?
Can I use neodymium magnets in an aquarium or salt water?
Yes, with plastic or epoxy coated magnets inside the water. See magnets in aquariums and salt water.
What other magnet coatings are available?
Electroless nickel, zinc, gold, silver, PTFE, parylene and Everlube on custom orders. See all coating options.
What's the difference between nickel and electroless nickel?
Electroless nickel is deposited chemically for a more even, more corrosion-resistant layer. See nickel vs. electroless nickel.