Q: With the flexible magnetic sheets, how strong can the magnet strength be? We are looking to hold items to the roof of a car at speed so the magnetic pull needs to be quite strong.

Magnetic sheets are thin and flexible. While this can offer advantages in many applications, it means the flexible sheet magnets are naturally magnetically weak and have little ability to support anything more than their own weight.

Most cars have body panels that are 2mm thick or less and do not provide an overly-strong attachment base for magnets of any kind. When attaching flexible sheet magnets to a car it is recommended that a 0.8mm thick sheet is used.

Thicker sheeting will always provide a better bond to the vehicle's body panel than thinner magnetic sheets. Attaching items other than wide, flat magnetic signage to a car will create a less aerodynamic shape. The item will be greatly impacted by wind and sheer forces as the vehicle travels along. Much will depend on the size and weight of what you want to magnetically attach to the car. The speed at which the car travels will also influence how well the magnet holds.

The more metal surface area that is in contact with the magnetic sheet, the stronger the bond will be. Frenergy has Rubber Coated Pot magnets that have extremely strong holding power but can bond to your car's bodywork without damaging the paint.

This category has magnets that bond strongly to your car body and there is a range of attachment options for mating the magnet to your non-magnetic item. These options include male thread attachment, female thread attachment, countersunk screw hole and even a cable tie attachment bracket. Choose the magnet that is strong enough to bear the weight of the item you want to attach and most suited to your requirements