Author Topic: How to fix a broken ferrite core?  (Read 5392 times)

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Offline ali6x944

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How to fix a broken ferrite core?
« on: May 30, 2016, 05:55:32 am »
Hi every one,
I was salvaging some inductors from old p.s.u and I accidentally cracked and broke one of the cores
Not meaning glue failure in an E type core but a real broken core ...
This is it:
https://drive.google.com/file/d/0B5vW-k7HbsL4OVBibTcxN3plOW8/view?usp=drivesdk
https://drive.google.com/file/d/0B5vW-k7HbsL4YlB0QXZiOUVDNUU/view?usp=drivesdk
https://drive.google.com/file/d/0B5vW-k7HbsL4MnJvTWphNWJSN1k/view?usp=drivesdk
 

Offline rs20

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Re: How to fix a broken ferrite core?
« Reply #1 on: May 30, 2016, 06:11:56 am »
Not all of your pics are publically viewable. Try viewing them from a incongnito tab to test if a random on the internet can see it.

More than likely you can just glue the bits back together. Sure, the inductor will be a little more "gapped" than usual, but it shouldn't have a particularly major effect? Maybe? Unless it was a totally ungapped core to start with.
 
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Offline ali6x944

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Re: How to fix a broken ferrite core?
« Reply #2 on: May 30, 2016, 08:21:40 am »
Should I use epoxy
 

Offline T3sl4co1l

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Re: How to fix a broken ferrite core?
« Reply #3 on: May 30, 2016, 08:54:53 am »
Superglue or epoxy will do, yes.  Position the fragments as well as you can.  If it's just a few pieces, this is easy.  If it's shattered into dust, consider locating a same-size replacement core (take careful measurements in case the original was gapped).

Tim
Seven Transistor Labs, LLC
Electronic design, from concept to prototype.
Bringing a project to life?  Send me a message!
 
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Offline ali6x944

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Re: How to fix a broken ferrite core?
« Reply #4 on: May 30, 2016, 02:24:58 pm »
Thanx everyone that was helpful :-+
 

Offline peter.mitchell

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Re: How to fix a broken ferrite core?
« Reply #5 on: May 30, 2016, 02:30:58 pm »
you want absolutely minimal glue and best possible fit together.
generally you put some glue on your finger, gently smear it over the surface, wipe it off your finger on to some towel, then tightly press the ferrite back together, and hold it until it holds itself, then you put a bit of glue on the outside to support it - on the outside it is fine to add as much glue as you want provided it doesn't get in the way of the coilformer/bobbin.
 
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Offline Arjan Emm

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Re: How to fix a broken ferrite core?
« Reply #6 on: May 30, 2016, 03:32:25 pm »
I would use superglue because it is water thin and leaves the smallest airgap. Makes shure there are no loose bits on the surface so they fit as snug as possible.
« Last Edit: May 31, 2016, 04:11:46 pm by Arjan Emm »
 
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Offline kavea

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Re: How to fix a broken ferrite core?
« Reply #7 on: May 31, 2016, 07:44:55 am »
Quote
Hi every one,
I was salvaging some inductors from old p.s.u and I accidentally cracked and broke one of the cores
Not meaning glue failure in an E type core but a real broken core ...
You can always glue it, BUT unfortunatelly it will decrease the effective magn├ętic permeability of your core since you will have some air gaps. So the inductance, if you have some wiring aroud the core will decrease.
 

Offline N2IXK

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Re: How to fix a broken ferrite core?
« Reply #8 on: May 31, 2016, 03:39:25 pm »
You might want to consider a steel-filled epoxy like "JB Weld" or similar to minimize the magnetic discontinuity at the glue joints.
"My favorite programming language is...SOLDER!"--Robert A. Pease
 
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Offline rs20

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Re: How to fix a broken ferrite core?
« Reply #9 on: May 31, 2016, 10:33:48 pm »
You can always glue it, BUT unfortunatelly it will decrease the effective magn├ętic permeability of your core since you will have some air gaps. So the inductance, if you have some wiring aroud the core will decrease.

If the core is an ungapped core, then yes, the decrease in inductance will be major.

However, if the core is already deliberately gapped, then there's every chance that the change in inductance will be negligible/within tolerance.
 
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Offline Raj

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Re: How to fix a broken ferrite core?
« Reply #10 on: July 03, 2016, 02:14:28 pm »
Fine Iron filled epoxy would be good, just clamp it firm, just enough for not to break it but to hold it together without any gap
Good Luck :-+
 


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