You'll likely want to experiment with different magnets to get just the right one. Ultimately you will need to know the size, shape, and strength or pull force. Hopefully, the following tips will help reduce the often-inherent trial and error process.
Tip 1: Do some research.
For advice on DIY projects or other crafts (hanging signage/artwork, scrapbooking, jewelry, magnetic spice racks etc), you may find valuable advice online from other individuals who have already done some of the homework for you.
Tip 2: Try to estimate the exact size and shape of the magnet you will need.
Start with estimating the footprint or area your magnet will be placed into or used for.
Do you think you need a disc magnet? A bar or a block magnet? Or a magnet with a hole or countersunk hole in the middle? What would be the best size?
Try to answer these shape and size questions first, keeping in mind that the larger the magnet, the stronger and possibly more dangerous it will be.
Tip 3: Pay attention to the magnetic pull force.
Every magnet, in addition to being listed by its exact size, also has a corresponding pull force rating. This tells you exactly how strong the magnet is and how much weight or stress it can hold in pounds and kilograms.
Sometimes you can estimate this according to functionality, such as what your magnet will be used for and how much weight or stress it needs to hold or absorb.
Another key is placement. Magnets will hold their listed pull force when mounted vertically, such as on the underside of a steel beam or banner.
When mounted horizontally, such as on the side of a refrigerator or file cabinet, gravity can dissipate the pull force rating by as much as 65 percent or more.
Tip 4: Order the minimum quantity of what you think you’ll need.
Order a magnet and see how it performs in your product or prototype. If the magnet or combination of magnets is too strong or too weak, you will have a much better idea of what to try next.