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How can I remove an epoxied rare-earth magnet.

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Forum topic by Combo Prof posted 04-25-2016 03:49 AM 1049 views 0 times favorited 21 replies Add to Favorites Watch
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Combo Prof

2377 posts in 740 days


04-25-2016 03:49 AM

Topic tags/keywords: question

I epoxied a 1/4 inch diameter 1/10 inch thick rare earth magnet into a 1/4 inch diameter hole into maple. I must have got the epoxy to thick, because it is not flush with the surface. Is there a way to remove it with out damaging the maple?

-- Don K, (Houghton, Michigan)


21 replies so far

View MrUnix's profile

MrUnix

4218 posts in 1661 days


#1 posted 04-25-2016 04:11 AM

Good luck with that one! The epoxy has now saturated the surrounding wood, so it’s there for good. You might be able to crack and dig out the magnet (they are pretty fragile) and re-drill, but it’s going to be a PITA.

Cheers,
Brad

-- Brad in FL - To be old and wise, you must first be young and stupid

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Combo Prof

2377 posts in 740 days


#2 posted 04-25-2016 04:17 AM

I may try the heat and pry out method but more then likely I just may live with it.
Maybe I can just recess the plate it is to stick to a little below the surface.
(This is to make a magnetic latch for a box.)

-- Don K, (Houghton, Michigan)

View Boxguy's profile

Boxguy

2174 posts in 1730 days


#3 posted 04-25-2016 04:33 AM

Don, why not just drill it out? Use a sharp point to set the bit center, then use the same bit to drill out the magnet.

When I use these magnets, I drill a snug hole, position the magnet where I want it, and drip in thin super glue to set it in place. Here is another hint…leave the magnets stacked up and use the stack and a rubber mallet to drive the bottom magnet into the hole. Lets you keep your fingers out of the way of the mallet when you are setting it in the hole to start with.

-- Big Al in IN

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conifur

955 posts in 614 days


#4 posted 04-25-2016 04:39 AM

I have done that, just take a chisel, not your best one and work around it a bit clearing the wood, then get under it and pop it out.

-- Knowledge and experience equals Wisdom, Michael Frankowski

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Combo Prof

2377 posts in 740 days


#5 posted 04-25-2016 04:42 AM


Don, why not just drill it out? Use a sharp point to set the bit center, then use the same bit to drill out the magnet.

When I use these magnets, I drill a snug hole, position the magnet where I want it, and drip in thin super glue to set it in place. Here is another hint…leave the magnets stacked up and use the stack and a rubber mallet to drive the bottom magnet into the hole. Lets you keep your fingers out of the way of the mallet when you are setting it in the hole to start with.

- Boxguy

Because I read in this article:

The magnets should not be machined or drilled, because drilling can cause them to shatter and break. The drilling activity produces a powder of tiny particles of metal, which is flammable. The heat produced by the friction of the drilling can also ignite the powder, and burn or melt anything nearby. There are instances of subjects who tried to drill through a neodymium magnet, and found their drill bits melted.

-- Don K, (Houghton, Michigan)

View terryR's profile

terryR

6316 posts in 1771 days


#6 posted 04-25-2016 08:52 AM

Heat.
Epoxy can soften.
Will probably discolor tha maple?

-- tr ...see one, do one, teach one...

View Don W's profile

Don W

17960 posts in 2030 days


#7 posted 04-25-2016 10:01 AM



Heat.
Epoxy can soften.
Will probably discolor tha maple?

- terryR

+1

-- Master hand plane hoarder. - http://timetestedtools.net

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Combo Prof

2377 posts in 740 days


#8 posted 04-25-2016 11:33 AM

Maybe I can heat the magnet with a soldering iron thereby controlling what gets heated and thus not discolor to much of the maple. What do you think of that? It may demagnetize the magnet, but I have more.

-- Don K, (Houghton, Michigan)

View hairy's profile

hairy

2384 posts in 2994 days


#9 posted 04-25-2016 11:46 AM


I must have got the epoxy to thick, because it is not flush with the surface.
Can you sand it down to flush?

-- stay thirsty my friends...

View JeffP's profile

JeffP

573 posts in 854 days


#10 posted 04-25-2016 11:58 AM

I agree with MrUnix. Rare earth magnets are super brittle.

I bought a stack of 20 of these not long ago. While I was working, I pulled about 5 of them off the end of the stack and was prototyping something with them…then I set those 5 back down about 5 inches away from the stack…you guessed it. The 5 joined their brethren in a quick hurry, and the force of their impact broke most of the 5 and a few of the ones in the larger stack.

A whack or two with a cold-chisel or center punch, and it will break up. Then dig at it with any small pointy tool you’ve got laying around. Pretty sure you’ll be able to break 99 percent of it out of there.

Then go at what little remains with a drill bit.

-- Last week I finally got my $*i# together. Unfortunately, it was in my shop, so I will probably never find it again.

View Don W's profile

Don W

17960 posts in 2030 days


#11 posted 04-25-2016 12:16 PM



Maybe I can heat the magnet with a soldering iron thereby controlling what gets heated and thus not discolor to much of the maple. What do you think of that? It may demagnetize the magnet, but I have more.

- Combo Prof

That should work. It doesn’t need to be very hot usually.

-- Master hand plane hoarder. - http://timetestedtools.net

View bonesbr549's profile

bonesbr549

1176 posts in 2529 days


#12 posted 04-25-2016 01:24 PM

I’d go get a hole saw slightly bigger than the magnet. Drill down around it, and pop it out. A plug cutter would do the trick. Fill the void and do it all again. I’ve removed several broken screws with this method.

-- Sooner or later Liberals run out of other people's money.

View putty's profile

putty

998 posts in 1069 days


#13 posted 04-25-2016 01:28 PM

I have dropped them on concrete broke them. If you took a punch or nail set and gave it a sharp hit right in the middle. I’m sure it would shatter.

-- Putty

View JayT's profile (online now)

JayT

4773 posts in 1673 days


#14 posted 04-25-2016 01:32 PM

If you have a soldering iron tip that you are willing to sacrifice, cut of the very end so that there the two electrodes no longer connect, then hit the magnet with that. The magnet now completes the circuit and heats up more evenly than applying the soldering iron in one spot. It doesn’t take as much heat as you might expect to start to break down the epoxy.

-- "Good judgement is the result of experience. A lot of experience is the result of poor judgement."

View distrbd's profile

distrbd

2227 posts in 1909 days


#15 posted 04-25-2016 01:36 PM

A plug cutter would do the trick. Fill the void and do it all again. I.

- bonesbr549


That’s what I was going to suggest, your second best option in my opinion is to use heat . Just read JayT’s idea and it might work very well ,I should try that myself .

-- Ken from Ontario, Canada

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