Sticking magnets together just means that you are combining the power of two magnets and creating a stronger. The powers of the combined magnets will definitely double but there are limitations to how much power can be acquired by doubling.
What are neodymium magnets?
These magnets are most commonly used in commercial applications and they are made from a special mix of neodymium, iron and boron alloys. These magnets are usually used in areas where strong are required like cordless phones etc. Neodymium magnets are preferred as they have higher energy and higher coercivity. However, as with other the power of the magnet diminishes towards the center of the of the magnet and is the highest along the periphery.
Why does the power double?
Using two neodymium can increase the power of the magnet on the whole. This is also referred to as stacking. For example, using a magnet with 10mm diameter and 2mm width and adding another with 10mm diameter and 2mm width to it will mean that this magnet will eventually be working as a 10mm diameter by 4mm powered version. This property is successfully used in arrange of commercial applications and it has proved to be very effective. However, along with the benefits, there are a few drawbacks as well.
• Magnets attract each other in opposite directions. That means you will have to place them with opposite poles together. This does increase the overall power of the. However, this creates a problem as well. As opposite poles are placed together, the total power of the magnet is much lower than expected. If you can find a way to hold the magnets together or clump them together so that they are aligned with same poles together, you will be able to get much more power in your stacked.
• The cross sectional area has to be increased more than the thickness to get the best gains from magnet stacking. However, if you extend the length more than the diameter of the magnet, it will not work. Power of the magnet does increase but it is a minimal difference which will not help.
Commercially, large companies do carry out stacking to double the power of a simple magnet. This is done only for specific occasions though and most companies prefer to use electro magnets which provide the right amount of attraction. If you are planning on stacking magnets for home use, we suggest you be very careful. Neodymium are very powerful and there have been reports being attracted towards each other with so much force that they can pinch body parts in the middle causing broken bones and crushed fingers. The magnets may strike each other with so much force that they may chip and shatter as well.