Tel: 972-516-0692
Easy Return Policy
satisfaction guaranteed
satisfaction guaranteed
Premium Products
we guarantee our quality
we guarantee our quality
100% Safe Shopping
256 bit SSL encryption
256 bit SSL encryption
Shop By Category
Shop By Brand
Shop By Brand
Ceramic Cup Magnets
Weatherproof & High-Temperature Round Base Assemblies
Ceramic Cup Magnets (Ferrite Round Base Mounting Magnets)
CMS Magnetics manufactures commercial-grade ceramic cup magnets (also known as ferrite pot magnets or round base assemblies) engineered for outdoor fixturing, washdown environments, marine mounting, and high-heat industrial applications. Each assembly houses an anisotropic Grade 5 or Grade 8 ceramic ferrite ring magnet enclosed inside a shallow, zinc- or chrome-plated mild steel cup. The steel cup completes an efficient magnetic circuit, redirecting rear and side flux lines forward onto the active contact plane to deliver 3x to 4x the clamping power of an unencased ceramic magnet while shielding the brittle ferrite core from direct mechanical impact.
Looking for extreme rare-earth pull force, rectangular channels, or raw ferrite rings? For maximum holding strength in a compact footprint, explore our Neodymium Cup Magnets. For linear door latches and extrusion mounting, view Ceramic Channel Magnets. If your project requires unshielded raw ceramic stock without a steel cup, see our Ceramic Ring Magnets or pair assemblies with Steel Magnet Strikers.
Inherent Weather Immunity
Ceramic ferrite oxide will not oxidize, pit, or rust when exposed to moisture or outdoor rain.
250°C Thermal Ceiling
Operates continuously in ambient heat up to 250°C (482°F) without irreversible demagnetization.
Steel Shunt Amplification
Low-carbon steel casing focuses flux into the open face, multiplying contact pull force up to 60+ lbs.
Integrated Center Hole
Center mounting hole accommodates standard flat-head bolts, screws, hooks, or eyelets.
Related Mounting Assemblies: Ceramic Cup Magnets Ceramic Channel Magnets Neodymium Cup Magnets AlNiCo Pot Magnets All Cup & Pot Magnets
Engineering Guide: Ceramic Cup Magnet Selection, Thermal Limits & Fixturing
Ceramic cup magnets offer the most economical clamping solution per unit volume across industrial, agricultural, and commercial hardware applications. While rare-earth neodymium cups provide peak saturation in micro spaces, ceramic ferrite assemblies dominate in environments where operating temperatures exceed 80°C (176°F), where direct weather exposure would corrode neodymium plating, or where budget dictates mass deployment.
Round Base Comparison: Ceramic Cup vs. Neodymium Cup Magnets
| Specification | Ceramic Cup Magnets (Ferrite Grade 5/8) | Neodymium Cup Magnets (NdFeB N35-N52) |
|---|---|---|
| Corrosion Resistance | 100% Rust-Proof (inert oxide; ideal for marine & outdoor) | Requires intact plating; susceptible to moisture corrosion |
| Maximum Operating Temperature | 250°C (482°F) continuous | 80°C (176°F) standard; 150°C high-temp special grades |
| Pull Force per Diameter | Moderate (5 lbs to 65+ lbs depending on cup OD) | Extreme (15 lbs to 300+ lbs in matching OD) |
| Cost Efficiency | Lowest cost per assembly (economical raw materials) | Higher cost driven by rare-earth elements |
| Common Mounting Uses | Outdoor signage, vehicle antenna mounts, gate catches, shop lights | Precision robotics, heavy machinery workholding, aerospace fixtures |
Magnetic Shunt Mechanics: How the Steel Cup Focuses Ferrite Flux
An uncased ceramic ring magnet projects flux symmetrically in 360 degrees, leaving the rear magnetic field unutilized. Enclosing the ring within a low-carbon steel cup fundamentally improves performance:
- Closed Magnetic Circuit: The high permeability of the steel shell channels flux lines from the rear pole through the cup base and outer lip directly to the contact face. When placed against a steel surface, the flux circuit closes through the mating steel, concentrating holding strength onto one working face.
- Protection from Edge Fracturing: Ceramic ferrite is a brittle sintered material that easily chips when subjected to direct metal-on-metal impacts. The raised outer steel lip absorbs kinetic energy during clamping, protecting the internal ceramic ring from mechanical damage.
- Shielded Rear Casing: Because the steel cup directs flux forward, stray magnetic fields behind the cup are effectively blocked, preventing metal debris from collecting on the rear side of the mount.
Load Engineering: Direct Perpendicular Pull vs. Vertical Shear Slide
Rated pull capacities represent direct perpendicular breakaway force (Case 1) against flat, clean, ground 1/2-inch thick low-carbon steel. When mounting ceramic cups vertically against gravity:
- Friction Coefficient Factor (μ): Smooth zinc-plated steel against smooth steel surfaces has a friction coefficient of μ ≈ 0.15 – 0.20. Expect a vertically mounted cup magnet to begin sliding at roughly 15% to 20% of its rated perpendicular pull force unless mechanically supported or pocketed.
- Rotational Torque vs. Channel Bases: Because circular cup magnets mount with a single central fastener, cantilevered loads can induce rotational spin. For applications requiring anti-twist alignment along narrow beams or door frames, utilize our rectangular Ceramic Channel Magnets.
- Non-Ferrous Mating: To mount ceramic cups to wood, fiberglass, or drywall, pair them with matching Steel Magnet Strikers.
Frequently Asked Questions
What are the primary advantages of ceramic cup magnets over neodymium cup magnets?
Ceramic cup magnets excel in three specific conditions: wet or outdoor environments (ferrite material is naturally rust-proof), high-temperature environments up to 250°C (482°F), and high-volume commercial budgets where ceramic assemblies provide cost-effective holding power compared to rare-earth alternatives.
Will the steel cup rust in outdoor weather?
While the internal ceramic ferrite ring is chemically inert and completely rust-proof, the outer steel casing is protected with sacrificial zinc or chrome plating. For harsh marine or salt-spray installations, applying a clear silicone or polyurethane sealant over the exposed steel edges provides long-term weather protection.
How do I attach ceramic cup magnets to my mounting surface?
Our ceramic cup magnets feature a central mounting hole sized for standard flat-head wood, sheet metal, or machine screws. Ensure the screw head seats completely flush or recessed below the outer steel lip to avoid creating a mechanical air gap between the magnet face and the steel contact surface.
Why does a ceramic cup magnet lose holding strength across an air gap?
The steel cup is specifically designed to create a tight, focused flux loop between the center magnet face and outer steel rim. Because this magnetic circuit is optimized for direct metal-to-metal contact, holding power drops off rapidly over air gaps, thick paint, or heavy rust. Direct contact against flat, low-carbon structural steel is recommended for full rated holding force.