Can magnets work through wood, glass, and plastic?
Short answer: yes. Wood, glass, plastic, cardboard, fabric, aluminum and most types of stainless steel allow a magnetic field to pass through almost unhindered. The problem is not the material, but the distance: the force drops off quickly. With small magnets, a distance of 1 mm often already halves the holding force; through 5 mm of material, often only 10–25% remains. Therefore, with thick material, you should use a larger or thicker magnet, or let two magnets attract each other instead of using a magnet and a steel plate.
Which magnet is right for your situation?
- Hidden closure through 3–5 mm wood (cabinet door, flap): use 2 x disc magnet Ø20 x 5 mm, which attract each other through the wood.
- Glass board or glass memo board (4–6 mm glass): disc magnet Ø10 x 5 mm for loose papers, 10 mm cube magnet for a few sheets at a time.
- Through a thick panel (5–10 mm): choose disc magnet Ø20 x 10 mm; it is thick enough to retain its force at a distance.
The stated holding force applies directly to thick steel. Through material, less remains; see the table below.
How much force remains? (indicative)
| Distance (material thickness) | Small magnet (Ø10 x 3 mm) | Larger magnet (Ø20 x 10 mm) |
|---|---|---|
| 0 mm (directly on steel) | 100% | 100% |
| 1 mm | ca. 40–55% | ca. 70–80% |
| 2 mm | ca. 25–35% | ca. 55–65% |
| 5 mm | ca. 5–10% | ca. 25–35% |
| 10 mm | < 3% | ca. 10–15% |
Rule of thumb: the thicker the magnet relative to the distance, the more force remains. A magnet that is at least as thick as the material it must pass through usually works well. Always test with the actual material.
Magnet + magnet or magnet + steel?
Through a thick panel, two magnets attracting each other work much better than a magnet on a thin steel plate. A thin plate (0.5–1 mm) quickly becomes saturated and only captures part of the field. With two magnets, however, pay attention to the poles: the north pole of one must face the south pole of the other. See why do magnets attract each other?
By material
- Glass (whiteboard, glass board): a glass board is 4–6 mm thick with a steel plate behind it. Regular ferrite magnets work poorly there; choose strong neodymium magnets of at least Ø10 x 5 mm or larger pot magnets.
- Wood: a magnet in a routed hole with a thin layer of wood in front (1–2 mm) remains invisible and still works well. Ideal for cabinet doors and hidden closures. See magnets for interior construction.
- Plastic and 3D prints: leave 0.4–0.8 mm of wall between the magnet and the outside. See magnets for 3D-printed applications.
- Fabric and leather: no problem; sewing magnets and racing number magnets are made for this.
- Aluminum and stainless steel: allow the field to pass through, but the magnet will not stick to them.
Through which materials does a magnet work poorly?
Only ferromagnetic materials such as steel and iron (and mu-metal) deflect the field. A steel plate between two magnets therefore acts as a shield, not as a conduit. Thick steel cabinets and metal frames can shield a magnet on the other side.
Frequently asked questions
Does a magnet work through a refrigerator door?
A refrigerator door is made of steel, so a magnet sticks well to it, but does not work through it. The steel is thin (ca. 0.6 mm), so a strong magnet only achieves part of its stated holding force there.
Which magnet for a glass memo board?
Choose neodymium magnets of at least Ø10 x 5 mm, or 10 mm ball and cube magnets. For heavy papers, use a pot magnet.
How thick can the wood be?
With two Ø20 x 5 mm magnets, a closure through 3–5 mm wood still works perfectly. For more than 10 mm, choose larger magnets or thin the wood on site.
Read also
Need help choosing? Use the Magnet Advisor or contact us.
