Ferrofluid cleaning question (KEF C55)

[tista]

Hi gang. Need some advice. Trying to put together a vintage system for a friend. Picked up some KEF C55 bookshelf speakers and one of the speakers has the gummy ferrofluid muffled tweeter problem. Tweeter works, but is clearly hampered.

Can I simply take it apart and clean the ferro-goo out of the gap and put it back together? I know the Ferro fluid serves some purpose, and can be bought from Parts Express, but feel like I've done this before with some MB Quart tweeters and they sounded fine after reassembly without new ferro fluid.

Thoughts?

 

[cademan]

Ferro fluid is to keep them cool.

 

[tista]

Ferro fluid is to keep them cool.

Yeah, I get that. But is it actually necessary? Feels like a thing of the past, maybe for a reason?

 

[reardonp6]

I feel it is necessary, I just run a paper business card around the ferro-goo to clean it out. I then replace it with new Ferro fluif of the same viscosity. If your going to the trouble of pulling the tweeter you might as well do it right while you have it out.

 

[cademan]

Yeah, I get that. But is it actually necessary? Feels like a thing of the past, maybe for a reason?

If you don't want to burn up your tweeter, yeah, it is necessary.

 

[tista]

I feel it is necessary, I just run a paper business card around the ferro-goo to clean it out. I then replace it with new Ferro fluif of the same viscosity. If your going to the trouble of pulling the tweeter you might as well do it right while you have it out.

I ordered the ferrofluid already as I agree with this logic.
Thanks for the reply!

 

[mitsos]

When you listen in high levels for a long time (lets say more than 1 hour) and you touch the tweeters you will feel that they are burning.
This is why the tweeter needs the ferrofluid.
But if you listen music at low to medium levels without overheating the tweeters then you are safe even without ferrofluid.
Usually the manufactures that use ferrofluid in their tweeters is because they realized during testing that they can get really hot.
On the other hand there are a lot of newer tweeter designs that do not use it anymore.

 

[tista]

Thanks for all the feedback. I'm post pics of the repair for others interested.

 

[cpt_paranoia]

I feel it is necessary, I just run a paper business card around the ferro-goo to clean it out. I then replace it with new Ferro fluif of the same viscosity.

I agree it needs to be removed.

Ferrofluids are a suspension of nanoparticles in a fluid. If we assume the fluid evaporates, leaving the nanoparticles behind, if we just inject some more, we have double the amount of nanoparticles, which I'm naively going to guess will alter the properties of the resulting goop; probably too viscous.

The fluids used seem to be water or organic solvent of some kind, so those might be uses to clean the old residue.