How Can I Keep a Magnet From Sliding Down a Vertical Surface?
Give the weight something to rest on, add grip, or add pull force. On a wall, only friction keeps a magnet from sliding, and that friction is about 15 to 25% of its rated pull force. The most reliable fixes are a ledge, lip or screw under the item so the magnet only has to hold it against the wall; rubber-coated magnets for more grip; and enough total pull force, 7 to 10 times the weight (the high end on thin sheet steel), spread across several magnets.
Why Does a Magnet Slide Down a Wall?
A magnet’s pull force presses it against the steel, but the item’s weight pulls along the steel, not away from it. Only friction resists that sliding, and for a nickel-plated magnet on smooth steel it’s roughly 15 to 25% of the pull force. So a magnet rated 20 lb starts to slide at about 3 to 5 lb. See what shear force is and does a 20 lb magnet hold 20 lb?
7 Ways to Stop a Magnet from Sliding
1. Add a Ledge, Lip or Stop
The most reliable fix. A small shelf lip, bracket, screw or rail under the item carries the weight, and the magnet only holds the item against the wall, which uses its full pull force instead of a fraction of it.
2. Use Rubber-Coated Magnets
Rubber grips steel far better than smooth nickel plating and protects painted surfaces. Rubber Coated Magnets, including our rubber pot magnets and hooks, are made for vertical surfaces. Our 66 mm Rubber Hooks list a sideways rating of 16 lb.
3. Add Enough Total Pull Force
Add up the listed pull force of all the magnets and aim for 7 to 10 times the weight. Use the high end, 10 times, on thin sheet steel such as a fridge door or steel door. Our magnet calculator does the math.
| Item weight | Total pull force (7 to 10×) | On thin sheet steel (10×) |
|---|---|---|
| 1 lb | 7 to 10 lb | 10 lb |
| 2 lb | 14 to 20 lb | 20 lb |
| 5 lb | 35 to 50 lb | 50 lb |
| 10 lb | 70 to 100 lb | 100 lb |
4. Spread Several Magnets Across the Item
Several magnets spread across an item resist twisting and peeling better than one big magnet in the middle. On thin steel, smaller magnets also lose less of their pull than large ones, so a few small magnets often hold more than one large one; see steel thickness.
5. Keep the Load Close to the Wall
A hook or bracket that sticks out acts as a lever and pries the top of the magnet off the steel. Keep heavy items tight to the surface, and put the magnets near the top of the item.
6. Improve the Steel Surface
Clean, flat, dry steel grips best. Oil, wet paint and dust make magnets slip. Thicker steel adds pull, so a Steel Plate behind a thin panel helps.
7. Hang It Below Steel Instead
If you can mount under a beam or shelf, the load pulls straight off the steel and gets the full rating.
Do Anti-Slip Pads Help?
A thin rubber or silicone pad between the magnet and the steel adds grip, but it’s also an air gap that lowers the pull force. A 0.5 mm (0.02 in) gap leaves a 1/2 × 1/8 Inch disc only about 55% of its pull, while larger and thicker magnets lose less through the same gap. Keep pads thin, and test on your real surface; a rubber-coated magnet usually does the same job with less guesswork. See air gaps.
Example: A 3 lb Steel Door Sign
A steel door is thin sheet steel, so aim for the high end: 3 × 10 = 30 lb of total listed pull force. Four 1/2 × 1/8 Inch N52 Discs (32.6 lb together) spread around the sign work better than one large disc, because small magnets lose less on thin steel. Better still, add a small lip at the bottom of the sign so it can’t slide at all.
Don't Trust Magnets Alone Overhead
Where a sliding or falling item could hurt someone or damage something, add a ledge, screw or safety cable.
Takeaway
A magnet slides because friction carries the load on a wall. Give the weight a ledge to rest on, use rubber-coated magnets for grip, size for 7 to 10× the weight (10× on thin steel), spread magnets out and keep the load close to the wall.
- Rubber Coated MagnetsScratch-Free Grip
- Pot (Mounting) MagnetsSteel Cup Focuses the Pull
- Magnetic HooksRated from 9 to 55 lb
More Questions About Magnets on Walls
What is shear force?
A load along the steel surface instead of away from it; only friction resists it. See shear force.
How many magnets do I need to hold my item?
Aim for 1.5× the weight for straight pulls and 7 to 10× for sliding loads. See how many magnets you need.
Does steel thickness affect magnet strength?
Yes. Thin steel saturates, and large magnets lose the most. See steel thickness.
Why won't my magnet stick?
Usually the surface isn’t magnetic steel, the steel is thin, or a gap or sliding load is to blame. See why a magnet won’t stick.