One often-overlooked way to store or hold our things is to use magnets, and to that end, disc magnets can be especially useful. Disc magnets, (as the name would imply) are simply magnets in the shape of disks, and in actuality, we see them all over the place and simply overlook them. They are used to hold our binders and portfolios closed, as 'thumbtacks' for bulletin boards, and even to hold up our favorite picture on the refrigerator. In the case of the really strong ones, they can even be used as door catches or to pull out a twisted cabinet door and hold it in the correct place.
There are three types of disc magnets; with each one having its own respective strengths and weaknesses. The first type (and most common due to its cost-effectiveness) is the ceramic magnet. The ceramic disc magnet is of medium strength and is the lowest cost one on the market today. The grade 5 magnet is generally the most common of these, but strengths of up to 10 are available, and are often used for more demanding technical applications. The other strength of the ceramic disc magnet is that it requires no special care, such as protection from surface rust. It is commonly covered with a thin film of magnetic powder.
With a grade of 18-33 (18-26 being the most common), Samarium disc magnets are much more powerful than their ceramic counterparts are very temperature stable (their properties are fairly stable up to 570 degrees F), and also do not require protection from surface rust. Unfortunately, however, they are also expensive, and very brittle. One must be careful in working with them, as they can chip or break if dropped or snapped together. For any situation requiring high strength at a high temperature however, they are often the best bet.
Lastly, but certainly not least however, with a grade range of 35 -55 (with 35, 40, 42, and 45 as the most common) Neodymium or 'rare earth' disc magnets are the most powerful commercially available magnets on the market. Much, like the Samarium magnet, it is brittle however, and can break if snapped together. One must also take care when handling these, because with the strength of the pull, they can also painfully pinch fingers between them when they are near each other or steel. They are also more costly than the ceramic magnets, but can also hold a much greater load. Unfortunately however, they are not as strong in high temperatures, and as such, should not be used in temperatures over 130 degrees F. Additionally, these magnets are not protected with coating or plating, and as such, may rust if conditions are humid.
With an understanding of the type and application of disc magnets, they can be great tools and useful for holding a myriad of things together, in place or out of the way. As with anything however, one should always check to make sure they have the correct tool for the job at their disposal before they try to use it.