Have you cut a magnet?

First off have you tried cutting them? You would probably need a diamond saw.

If you do cut them they will each have a north south pole though the heat generated by the cutting process will weaken them. Get it hot enough and you will demagnetize them.

Pete

I doubt he'll get enough heat to demagnetize them. About 8 years ago we had some steel bar that was running About 75-100 Gauss and even stress relieve temperatures didn't demagnetize them. Had to get up to past hardening temps at 1650 f to do it.

Cutting without destroying will be the real trick.

@TexasSP posted:

Cutting without destroying will be the real trick.

Why? Are all magnets made from really hard steel? Is brittleness what you are referring to?

My experience with trying to cut magnets - is that they are very brittle.  Have never found a way to do it neatly without making a mess.

Magnets can and are made with a variety of materials. Not sure what you mean by really hard steel. However in the steel world the harder the still is the more brittle it tends to be.  Steel is made up multiple characteristics which are application driven. Magnets as well are application driven.

Neodymium magnets are very brittle. They also appear to lose strength as low as 175 f so beware.

I would think the easiest to cut is alnico. Ceramic or ferrite magnets would likely shatter. 

I have considered using neodymium magnets in magnetraction engines. They actually might be too strong causing too much drag for the motor to overcome but if you wanted to try fitting them and an exact size match wasn't available I would try and get shorter ones and fill the gap with soft iron bar to maintain the field.

Pete

Now that I'm reading the comments about the difficulty in cutting, that answers a question that arose while replacing the worm gear in a truck with Lionel's original magnets. Both magnets appeared to have been cut in a very jagged fashion, and I wondered why? Brittleness and difficulty in cutting could certainly explain that!

Well, all that said, I wonder if I could stack up and JB Weld a small pile of the "button" neodymium magnets to accomplish the same end? I wouldn't have the luxury of being able to adjust the "length" of the stack, but I could get lucky, and get close to an exact fit.

Just saw Pete's comments while typing this - good suggestions, think i'll give it a go!

Make sure if using JB weld on magnets that they're not smooth surface. The JB weld needs something to grab. Especially with neodymium the power to grab can pull right away from JB weld.  Been there done that.

From FAQ page at K&J Magnetics:

K&J article about adhesives for Nd magnetics including interesting comment about JB Weld.

I buy my Nd magnets from K&J; they have a huge assortment in all shapes and sizes.  Perhaps they have some that don't require cutting for your application.

If these are to be used in magnetraction engines no adhesive will be necessary. They are enclosed in a cylinder and will hold themselves together. I have stacks of dozens stuck to the side of my dehumidifier that haven’t budged in five years.

Pete

My two toolboxes are were I store my magnets, there is an assortment of them all over the front, they've been there for years as well.

Pete, I wish I could find a dehumidifier that would last five years!

Stan, I've also bought a bunch of magnets from K&J, they're my go-to source if I need a magnet.  Interesting fact about how hard the material is, I've never tried to cut it, and I can see it would be "interesting".  That part about catching fire makes me think of magnesium.

@gunrunnerjohn posted:

...

That part about catching fire makes me think of magnesium.

Made me think of releasing the "magic smoke" with our electronics.  I wonder if guys that mess with Nd magnets also dread the "magic smoke".  

I know if you take two of the K&J 2x1x.5 magnets and get them too close to each other on the bench they'll do some serious damage!  Don't ask me how I know this.

John, the dehumidifier the magnets are stuck to hasn’t worked in years. Its now a stand for my mini drill press. We avoid throwing things away, you never know when you’ll find a use for it.

Pete

Well, I feel a little better Pete!  I get at most about three years out of the 70 pint dehumidifiers before I have to replace them.  Several have crapped out so quickly that they got replaced on the one year warranty!  I have another dead one sitting here, need another drill press stand?

I had better luck piping dehumidifiers versus using the reservoir. Can't remember the brand but bought at Lowe's. First one lasted 5 years in tool room in insulated metal building. That's in the high humidity Houston weather.

As for high powered magnets, their attraction can be dangerous. I hurt my thumb pretty good getting the skin between two neodymium magnets several years back. They were round about the size of a quarter.

I always run humidifiers to a drain, no reason at all to screw around with the bucket several times a day!   I currently have one that has the pump, but already the pump is getting noisy, something that I've heard is a major issue with most of these.  I'm going to have to figure out something more permanent for my dehumidifiers, it's getting old buying them all the time.

I got a real demonstration of the power of Neodymium magnets years ago at my brother's house.  He had some from wind generators, and he had a couple of them on the workbench.  They were a good six inches apart, and he bumped one of them and they suddenly felt a strong attraction.  Although they started out as cylindrical magnets over an inch around and about three inches long, there wasn't a piece larger than an inch long after the carnage!  There were sharp shards of magnet all over for quite a distance.  We both got several little cuts from flying magnet pieces, I'm glad I was wearing glasses!

My two got together on the bench from about 1 inch away, one dropped out of my hand and landed next to the other one.  One was pieces, the other one only had a corner knocked off.

I keep this one with the missing corner stuck to a parts cabinet on the workbench, it's great for magnetizing tools.  I use the Radio Shack VCR eraser to demagnetize them if I need to.

Funny how the discussion evolved into dehumidifiers.  I have had 2 of them replaced on warranty in the last 5 years.  1 was about 5 years old and was under recall for fire risk and the other gave some code, which also indicated some sort of failure covered by warranty.  In both cases, I got full refunds, even though one was 5 years old.  

I understand about the ease of running them into the drain / sump, but I stopped doing that 5 years ago, when the one that was running into the sump crapped out, but the fan continued to run.  My other one was on the recall list and I had disabled it and was waiting for the refund before getting another.  So I had no operating dehumidifier and did not realize it, until I discovered mildew growing on my gargraves wood ties.  I just thought it was very humid that summer and the single one running was not up to the task.  A mistake I will never make again.  Went out and bought 1 that day.

I now have two 70 pint dehumidifiers running in my basement, neither draining to the sump.  It takes 2 to 3 days for both to fill up and trip off.  However, I know they both are running!  The gargraves track is long gone, replaced with Lionel tubular, with steel ties.

NWL

Getting back to Geopegs question, about missing magnets, the later Alco's didn't have the bar magnets, they used magnetic axles instead. 

OK, a bit of a summary here.

1. Cutting magnets sounds difficult and like it would need some specialized tooling. Not worth it to me, I'll buy the precut ALNICOs first. 

2. It also sounds dangerous - I have certainly heard stories about bloodied, flattened skin when it comes to the really strong ones. Didn't really think about them shattering in more or less an explosion if they got too close - thanks for that heads up, @gunrunnerjohn !!

3. Thanks to @stan2004 for the heads up on the JB Weld and neodymiums. Again knew about it, just didn't even think about the magnetic pulling on the steel pieces!

4. Thanks to @Norton for your thoughts - I was also worried about the neodymiums being potentially too strong!

5. Thanks to everyone else for your thought and for chippin' in!

6. I also learned what a PIA dehumififers can be - 'course I already knew that, been running one (or more) in my basement in rainy Ohio for a lotta years. Don't need 'em now that I'm living on a slab in southeast Tennessee!

George