How to fix a broken ferrite core? - Page 1
Forum section: electronics / repair

author: ali6x944
author_rank: Frequent Contributor
timestamp: May 30, 2016, 05:55:32 am
content: Hi every one,I was salvaging some inductors from old p.s.u and I accidentally cracked and broke one of the coresNot 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=drivesdkhttps://drive.google.com/file/d/0B5vW-k7HbsL4YlB0QXZiOUVDNUU/view?usp=drivesdkhttps://drive.google.com/file/d/0B5vW-k7HbsL4MnJvTWphNWJSN1k/view?usp=drivesdk

author: rs20
author_rank: Super Contributor
timestamp: May 30, 2016, 06:11:56 am
content: 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.

author: ali6x944
author_rank: Frequent Contributor
timestamp: May 30, 2016, 08:21:40 am
content: Should I use epoxy

author: T3sl4co1l
author_rank: Super Contributor
timestamp: May 30, 2016, 08:54:53 am
content: 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

author: ali6x944
author_rank: Frequent Contributor
timestamp: May 30, 2016, 02:24:58 pm
content: Thanx everyone that was helpful

author: peter.mitchell
author_rank: Super Contributor
timestamp: May 30, 2016, 02:30:58 pm
content: 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.

author: Arjan Emm
author_rank: Regular Contributor
timestamp: May 30, 2016, 03:32:25 pm
content: 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.

author: kavea
author_rank: Contributor
timestamp: May 31, 2016, 07:44:55 am
content: QuoteYou can always glue it, BUT unfortunatelly it will decrease the effective magnétic permeability of your core since you will have some air gaps. So the inductance, if you have some wiring aroud the core will decrease.

author: N2IXK
author_rank: Frequent Contributor
timestamp: May 31, 2016, 03:39:25 pm
content: You might want to consider a steel-filled epoxy like "JB Weld" or similar to minimize the magnetic discontinuity at the glue joints.

author: rs20
author_rank: Super Contributor
timestamp: May 31, 2016, 10:33:48 pm
content: Quote from: kavea on May 31, 2016, 07:44:55 amIf 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.

author: Raj
author_rank: Frequent Contributor
timestamp: July 03, 2016, 02:14:28 pm
content: 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 gapGood Luck

author: jorgemef
author_rank: Regular Contributor
timestamp: May 27, 2022, 11:49:46 am
content: Hello,Just for comparison I am adding two photos for two cores I bought in Aliexpress. One came broken/cracked, and flux is in order of 10 times less.Cheers,Jorge

author: jonpaul
author_rank: Super Contributor
timestamp: May 27, 2022, 12:22:00 pm
content: Very sorry cores are delicate céramique, so you cannot fix it, like a ceramic vase...any glue creates an air gap, and the glue loosening when power dissipating heats the core.we just discard broken coresj

author: blackfin76
author_rank: Regular Contributor
timestamp: November 23, 2022, 09:14:36 am
content: Ferroxcube did some interesting test gluing E-cores with epoxy and acrylic based glues.Epoxy glues come out as best but acrylic is also good.Find the document inhere