Making your own fridge magnets

Magnetic sheet you print at home is a thin layer of flexible magnetic material (ferrite powder bound into a rubber-like sheet) with a printable coating on one face. It is sold in the UK in A4 and A3 sheets, and sometimes as pre-cut business-card or photo sizes, through most large stationery and craft retailers. It is a different product from the magnetic sheet used by promotional print firms, and knowing the difference before you buy saves a wasted sheet.

Thickness and what it means for you

Craft magnetic sheet is commonly sold at around 0.4 mm to 0.5 mm, thinner than the 0.6 mm or 0.75 mm stock a trade printer would typically use for a promotional fridge magnet. A thinner sheet holds itself and a single photo print to a clean ferritic steel door without trouble, but it will not hold extra weight: do not expect an A4-sized home-printed sheet to hold a stack of paper the way a thicker, professionally cut magnet might. If you want to check what a given thickness can realistically hold, see Will It Stick? Magnet Strength, Thickness and What It Can Hold.

Inkjet, not laser

Printable magnetic sheet is designed for inkjet printers. The coating absorbs liquid ink and lets it dry on the surface. A laser printer works by fusing toner to the page with heat, typically well over 150°C, and that heat can warp the sheet, melt the printable coating, or damage the printer's internal rollers and fuser unit. Most manufacturers state inkjet-only on the packaging, and it is worth reading that line before you feed a sheet through any laser printer, including the multifunction one in an office that was not bought with this in mind.

What the printed result actually looks like

An inkjet print on magnetic sheet is not laminated, so there is no protective film over the ink the way there would be on a professionally printed magnet. The surface stays slightly matte, colours can look less saturated than the same image printed by a trade printer, and the print is vulnerable to water, fridge condensation and finger grease over time, since nothing is sealing it. A professionally printed magnet usually carries a lamination (a clear film bonded over the printed face) that protects the ink and gives a gloss or matte finish; home-printed sheet has none of that, so treat it as a short-lived, personal-use result. If you are printing a photo and want to check the file will come out sharp, the Artwork Size and Resolution Checker will tell you whether the image resolution is high enough before you print it.

A magnet you make at home does not have to start with printed magnetic sheet. Three other constructions turn up regularly in craft projects: self-adhesive magnetic backing stuck behind an existing image, a resin dome poured over a printed insert, and a bottle cap converted into a magnet. Each works by a different mechanism, and each has a different failure mode if the magnet does not hold or the construction is not safe for a household with children.

Self-adhesive magnetic backing

This is a flexible magnetic sheet (ferrite powder held in a rubber or polymer binder) with adhesive already applied to one face, sold as strips, dots or pre-cut circles. You stick your own photo, card cut-out or printed image to the adhesive side. The holding power still comes from the magnetic sheet underneath, not the adhesive, so a 0.4 mm strip behaves the same as any other 0.4 mm flexible magnet against a steel door. The adhesive is usually the weak point: cheap peel-and-stick strips can let go of a heavier card backing over time, especially in a warm kitchen, so a stiffer card or a stronger double-sided pad tends to last longer than the strip supplied in a craft pack.

The resin-dome method

A resin dome (also sold as an epoxy dome) is a clear, raised disc of cured resin bonded over a printed paper insert, the construction behind most souvenir and bottle-cap magnets. The dome magnifies and protects the image underneath but contributes nothing to how well the magnet sticks. The magnet itself, whether a hard ferrite disc or a small neodymium disc, is glued flat to the back of the insert after the resin has cured, and it is that disc's own pull force that determines whether the finished magnet will hold on a fridge door. If you are testing whether your fridge door will take a magnet at all, the paperclip test described in Will It Stick? Magnet Strength, Thickness and What It Can Hold works before you invest in resin.

Bottle-cap magnets

A bottle-cap magnet is built from a flattened metal or plastic cap, a printed paper insert trimmed to fit inside it, a resin dome poured over the top, and a magnet glued to the underside once everything has cured. Because the finished piece is small and the resin adds weight, the magnet glued to the back is almost always a small neodymium disc. That choice of magnet material is exactly where the safety question below applies.

The rule for neodymium discs in a household with children

Small neodymium magnets are strong enough that two or more, if swallowed separately, can attract to each other across the walls of the intestine and cause serious internal injury. If a child or anyone else is thought to have swallowed a magnet, the advice is to call 999 or NHS 111 and state clearly what was swallowed, without waiting to see whether symptoms appear. Do not use loose neodymium discs in any craft project intended for a household with young children, and read the full position, including how the Office for Product Safety and Standards treats these products, in Small Magnets, Children and Pets: The Safety Position before starting a bottle-cap or resin-dome project. If you are choosing between materials for the construction itself, What a Fridge Magnet Is Made Of, and Which Kind You Are Buying sets out what hard ferrite and neodymium each do and where they are used.