We had a project going on where we need to mount some antenna to the top of a water tower, and penetration is not allowed. While researching options for mounting with magnets, I’ve ran across a very powerful magnet. This magnet I was just reviewing has some very extremely impressive specifications.
Dimensions: 4″ x 4″ x 2″ thick
Tolerances: ±0.004″ x ±0.004″ x ±0.004″
Material: NdFeB, Grade N52
Plating/Coating: Ni-Cu-Ni (Nickel)
Magnetization Direction: Thru Thickness
Weight: 138.8 oz. (3934 g)
Pull Force, Case 1: 1226.5 lbs
Pull Force, Case 2: 1226.5 lbs
Surface Field: 4933 Gauss
Max Operating Temp: 176ºF (80ºC)
Brmax: 14,800 Gauss
BHmax: 52 MGOe
A 4″ by 4″ by 2″ thick N50 neodymium magnet will only lead to death and sorrow.
I’ve previously used big magnets to mount to structures like water towers where penetration was frowned apron. For instance, in the municipality of small town Missouri there is a tripod antenna mounted to the top of a water tower. We used six 2″ by 2″ by 1″ thick N40 neodymium magnets. I took three sections of 2″ by 4″ by 3/4″ thick steel stock, drilled a 5/16″ hole and threaded it, and stuck two of the N40 magnets on it side by side.
My tower climbers/installers were skeptical when I told them to measure out where they wanted them on the tower and to place them very carefully preventing any fingers that they wanted to keep out from between the magnet and the steel dome of the water tank. I told them to take a section of 2′ by 4′ lumber and a big hammer to “skoot” the mounts small distances once they place them…
I packaged each of these 3 mounts in a 1′ by 1′ by 1′ cardboard box with a shit load of packing material. The climbers had trouble getting the boxes up the tower, they kept sticking to the ladder.
When they came down off the topside, they were not skeptical anymore. They told me after they had all 6 magnets in place, and the tripod bolted to it, they tried as hard as they could to budge it, but could not. They both pulled laterally at the top of the mount where they had the most leverage, and gave up when they were worried about breaking the tripod.
The municipality that owns the tower gave us permission to use the tower, but not to drill, weld, clamp, or epoxy anything to the tank.
What would almost certainly happen if you ordered the afore mentioned Giant N52 is that as soon as you unpacked it from that big crate it ships in you would be immediately impaled and/or crushed to death by anything ferrous based in the room in which you opened the crate.
Be careful, big magnets like this one can hurt you! http://www.kjmagnetics.com/proddetail.asp?prod=BZX0ZX0Y0-N52&cat=168