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(closed) 24 years experience----Don't do it!

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Forum topic by papadan posted 12-09-2016 01:18 AM 2765 views 0 times favorited 88 replies Add to Favorites Watch
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papadan

3584 posts in 3205 days


12-09-2016 01:18 AM

Topic tags/keywords: tip

Lets talk magnets for a minute! I see products all over that use magnets to hold tools, knives, and even guns, in place. The weak kitchen knife magnetic racks are just fine, not strong enough to cause any problems. These Rare Earth magnets are great, they are small, yet very strong. Keep them away from your valuable tools, knives, and guns. I’ve been seeing a lot of hangers and concealment devices on the market, a magnet the size of a dime can hold a pound of steel, and they are using way bigger magnets than just a dime size. OK, let me explain, I spent the last 24 years of my career working on overhead cranes and hoists. All of my work was governed by OSHA, ANSI, and the CMAA. My work included both Die-Chem and Magnaflux testing of all hooks, chains and load bearing members and attachments. Both of these processes were the methods of detecting cracks or defects in the solid steel parts. Die-Chem is just like it sounds, clean all dirt, rust or paint off the steel. Apply a penetrating solution and let it dry. Then spray on an activator that will leave a darker colored streak following any crack or crevice in the steel. Cracks that are too small to be seen or felt by human eyes or fingers. This method works very well, but is extremely time consuming with cleaning, stripping the metal and waiting for the penetrant to soak in and dry. Most companies can’t have their equipment out of service that long. That is what lead to Magnaflux testing. With Magnaflux, a strong magnetic field is applied across the hooks or sections of steel. The magnetic field aligns all the steel molecules, then a colored iron powder is sprayed across the steel. Any cracks, no matter how small, will be seen by a fine sharp line of the iron powder. If there is an internal defect in the steel such as an air bubble from casting, the iron powder will create a sharp line circling the defect. The powder comes in different colors so it will show up on painted surfaces. OK, long winded, I know, but here is the point of this post. When the molecules of the steel align from the magnetism, the steel becomes brittle and will break easy! After the magnaflux test, the steel has to be hit with a steel hammer to shock it and knock the molecules back out of line so that they are all intertwined and not brittle. I have seen hoist hooks that snapped in half because a service tech didn’t believe the magnet could actually realign the molecules of solid steel and he didn’t shock the hooks. With my experience in strong magnetism, I will not use them to mount or hold my valuables. I would hate to have a $100 dollar hunting knife or any of my Two Cherry’s carving knives snap in two when I’m using it, and just think about what could happen when a hand gun is fired under strong magnetized conditions. I use a lot of the rare earth magnets in wooden tools to hold them in place and even trinkets to hold them onto the fridge, but I keep them away from valuable or dangerous items. I’m through rambling now!


88 replies so far

View mrbob's profile

mrbob

182 posts in 406 days


#1 posted 12-09-2016 02:18 AM

Do you know what a paragraph is???
I quit reading after the 3rd sentence
???

View woodbutcherbynight's profile

woodbutcherbynight

3645 posts in 2246 days


#2 posted 12-09-2016 02:54 AM

Tough read, rather long but interesting.

-- Live to tell the stories, they sound better that way.

View johnstoneb's profile

johnstoneb

2640 posts in 2009 days


#3 posted 12-09-2016 03:51 AM

Can you give a source for this. I have magnafluxed things before and had them magnafluxed and never hit one with anything when done. Never seen a problem afterwards.

-- Bruce, Boise, ID

View lew's profile

lew

11845 posts in 3592 days


#4 posted 12-09-2016 04:06 AM

Interesting.

I knew the physics principles that occur when metal is magnetized but never realized that the molecular structure was permanently altered. I had been taught that the magnetic domains were realigned more so than the molecular arrays.

-- Lew- Time traveler. Purveyor of the Universe's finest custom rolling pins.

View Redoak49's profile

Redoak49

2894 posts in 1825 days


#5 posted 12-09-2016 04:24 AM

I could not pass this up and let it stand as written.

As a metallurgical engineer working in steel my entire career, I find your discussion without any merit. I have participated in and read hundreds of steel related failure analysis and NEVER read one from an accredited source citing magnets causing a failure of a steel part due to some magnetic rearrangement of the structure.

Mag particle and eddy current are commonly used to check thing like crane hooks, welds and gears without any ill effects. I have never observed any detrimental effects of magnetism on samples using a metallograph or electron microscope to examine steel.

Large electromagnets are very commonly used to move all kind of steel…plates, billets, bars etc with no ill effects.

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papadan

3584 posts in 3205 days


#6 posted 12-09-2016 04:34 AM



Can you give a source for this. I have magnafluxed things before and had them magnafluxed and never hit one with anything when done. Never seen a problem afterwards.

- johnstoneb


My training and 24 years experience.

View WillliamMSP's profile

WillliamMSP

1084 posts in 1441 days


#7 posted 12-09-2016 04:56 AM

I’m still trying to wrap my mind around:

Problem – material is dangerously brittle
Solution – smack it with a hammer.

-- Practice makes less sucky. (Bill, Minneapolis, MN)

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papadan

3584 posts in 3205 days


#8 posted 12-09-2016 04:57 AM



I m still trying to wrap my mind around:

Problem – material is dangerously brittle
Solution – smack it with a hammer.

- WillliamMSP


Just mind boggling, ain’t it?

View ArtMann's profile

ArtMann

686 posts in 653 days


#9 posted 12-09-2016 05:19 AM

I’m putting my money on Redoak49’s analysis.

View Lazyman's profile

Lazyman

1504 posts in 1224 days


#10 posted 12-09-2016 05:32 AM

Hmm, Though I have no experience with a magnaflux test, it seems illogical that you would test the strength of a material with a device that could actually weaken it. Also, I’ve actually magnetized small pieces of iron by hitting them with a hammer while there is a magnet attached to it. That is probably the most likely outcome of hitting it with a hammer while the magnaflux is in use.

-- Nathan, TX -- Hire the lazy man. He may not do as much work but that's because he will find a better way.

View Rick_M's profile

Rick_M

10628 posts in 2217 days


#11 posted 12-09-2016 06:06 AM

I think this falls under the category of I don’t really understand what’s happening so I have woven a story that tries to make sense of it.

-- http://thewoodknack.blogspot.com/

View DirtyMike's profile

DirtyMike

637 posts in 739 days


#12 posted 12-09-2016 06:15 AM

Magnets have no place in my shop, that black magic is for the birds.

View Redoak49's profile

Redoak49

2894 posts in 1825 days


#13 posted 12-09-2016 11:58 AM

I hope that papadan will present some credible evidence.

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Redoak49

2894 posts in 1825 days


#14 posted 12-09-2016 11:58 AM

I think that papadan may have stated what he believed to be true but unfortunately it is not. I did a quick search looking for supporting evidence for his claim but could not find any.

View gargey's profile

gargey

862 posts in 612 days


#15 posted 12-09-2016 12:48 PM

Sounds like major BS to me. I have an engineering degree so I’m right 100.024% of the time.

Knowing how to take an x-ray does not equal understanding an x-ray. Hearing someone say that x-rays are powered by witch farts doesn’t mean they are (or aren’t).

showing 1 through 15 of 88 replies

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