Disc magnets are great tools for fixing something on the wall or any other vertical surface without using any adhesives, nails or hammers. Disc magnets are nothing but a piece of magnet, cut in the shape of a disc, flat on both sides, something like a thick coin. The ways you can use them are literally endless. They can be used for holding portfolios, pictures, art works and souvenirs on walls or doors. It is very common to see the surfaces of refrigerators, cupboards and cabins being decorated by objects held by disc magnets.
There are three types of disc magnets and each one of these has distinctive features and also specific usage. Each type comes with its own pros and cons and hence one needs to be careful while buying one. The most common type of disc magnet is the ceramic disc magnet. This is the cheapest variant available in the market and offers medium strength. Among the ceramic disc magnets, the grade 5 ones are commonplace but stronger ones, up to grade 10 strength are available, especially for technical purposes. Ceramic magnets do not need much maintenance and upkeep, neither do they need fully rust free surfaces to stick on. These disc magnets contain a thin coating of magnetic powder.
Samarium disc magnets are the second type which stand out from the ceramic ones in strength and robustness. While their strength can be found in the range of grade 18 to 33, strengths up to grade 26 are most common. Moreover, they can also withstand high temperatures. For these qualities, samarium magnets are costlier than ceramic ones. One drawback of these magnets is that they are brittle and hence require a little attention, but like their ceramic counterparts, they do not need rust protection as such, and hence are an excellent option for a great many purposes.
The third type of disc magnets in this series, are the strongest ones having strength varying from grade 35 to 55. These are called ‘rare earth’ magnets and are capable of holding very heavy objects. Neodymium magnets, as they are officially called can be so strong, that they can painfully pinch your finger or skin if it comes between two magnets, or one magnet and an iron surface. These are the most powerful commercial magnets and usually come in 35 to 45 grade strength. But all this strength comes for a price. These magnets are brittle, expensive and become defunct in high temperature (above 130oF). They are useful only in a small number of cases.
Disc magnets, are thus capable of doing a myriad of holding jobs. Some can be used for general purposes, while some are application specific. It is best that you choose one with the strength which your application demands