Some Background Information About Neodymium Magnets
“Neodymium magnets are a member of the Rare Earth magnet family and are the most powerful permanent magnets in the world. They are also referred to as NdFeB magnets, or NIB, because they are composed mainly of Neodymium (Nd), Iron (Fe) and Boron (B). They are a relatively new invention and have only recently become affordable for everyday use.
Grades of Neodymium
N35, N38, N42, N38SH…what does it all mean? Neodymium magnets are all graded by the material they are made of. As a very general rule, the higher the grade (the number following the ‘N’), the stronger the magnet. The highest grade of neodymium magnet currently available is N52. Any letter following the grade refers to the temperature rating of the magnet. If there are no letters following the grade, then the magnet is standard temperature neodymium.
Neodymium magnets are a composition of mostly Neodymium, Iron and Boron. If left exposed to the elements, the iron in the magnet will rust. To protect the magnet from corrosion and to strengthen the brittle magnet material, it is usually preferable for the magnet to be coated. There are a variety of options for coatings, but nickel is the most common and usually preferred. Our nickel plated magnets are actually triple plated with layers of nickel, copper, and nickel again. This triple coating makes our magnets much more durable than the more common single nickel plated magnets. Some other options for coating are zinc, tin, copper, epoxy, silver and gold. Our gold plated magnets are actually quadruple plated with nickel, copper, nickel and a top coating of gold.
Rare Earth magnets have a high resistance to demagnetization, unlike most other types of magnets. They will not lose their magnetization around other magnets or if dropped. They will however, begin to lose strength if they are heated above their maximum operating temperature, which is 176°F (80°C) for standard N grades. They will completely lose their magnetization if heated above their Curie temperature, which is 590°F (310°C) for standard N grades. Some of our magnets are of high temperature material, which can withstand higher temperatures without losing strength.”
Neodymium Magnet Information
More background information about neodymium magnets
More than you ever thought you could learn about magnetism and magnets. Here’s a full glossary with more details about magnets
PICKING A METAL DETECTOR
Magnets are cheap and easy, but I’m planning to replace my old Minelab metal detector in the coming year.
Getting back to the Meteorite Men, they had this to say on their website about their metal detector:
“If you’ve watched the award-winning series Meteorite Men on Science Channel, Discovery, Quest, or one of our other networks, then you’ve seen Geoff and Steve using the remarkable new Fisher F75. This extraordinary, top-of-the line detector is lightweight, perfectly balanced, extremely sensitive and the Meteorite Men’s hand-held detector of choice. And it’s a meteorite-finding machine.
The Meteorite Men used their F75s with great success at Canada’s amazing Whitecourt Crater, at Gold Basin in Arizona, at the famous Odessa, Texas meteorite crater, on the search for the legendary Tucson Ring, and at many other secret locations. If you want to up the odds of finding your own space rock, then you need to be using the best equipment out there, and that’s the F75.
The Meteorite Men are delighted to offer the very same unit that they’ve worked with throughout Season One and Season Two. Purchase directly from us and you will receive an exclusive color photo of Steve and Geoff, along with a genuine Sikhote-Alin iron meteorite (witnessed fall, Russia, 1947), so you’ll know exactly what a meteorite sounds like when your detector goes over it.”
Cost is about $1,249. That’s a little steep for most of us to justify to our Chief Budget Officer, so they advertise a “starter” GoldBug for about $550.
The White’s GMT costs about $800. I logged onto their site and got this report:
“The White’s GMT is a good choice for a low-end gold detector. By using the term ‘low-end’ I don’t mean cheap quality, just low price. The GMT can be purchased for about $800.00 new and $500.00 used. It does have some problems with Arizona’s heavily mineralized areas but can handle them decently with effort and practice. It can find gold as small as .02 gram with my experience and of course larger pieces. The fact that the GMT is a VLF or very low frequency detector means it can discriminate iron trash very well. In fact from my experience I’d say the discrimination is 99.9% accurate on trash. The digital scale normally shows gold at 25 or lower. What I am referring to is the digital ‘scale’ called ‘Probability of Iron’….
“The real upside to this unit is if you hunt old mine dumps or tailings piles. This is where the true dual purpose of this gold detector comes into play. While the more expensive pulse induction (PI) gold detectors will outshine the GMT or any VLF for the most part in the washes and hillsides, they won’t be able to match the GMT’s performance in mine dumps and tailings. Not only will the GMT find more gold in old mine tailings and mine dumps it will also tell you when a target is just an old nail or piece of iron junk accurately. It is also not affected by power lines like the more expensive PI units. It is also much lighter in weight than the more expensive PI units if that is a concern for you.
“So if you are looking for an entry level gold metal detecting gold prospecting machine that will do ok hunting washes and hillsides for gold and will absolutely shine in old mine dumps and tailings the GMT might just be the ticket.”