Celestion SL-6 corrosion on speakers - paint or oil to protect

[MaccaAu]

Hello,

My Celestion SL-6, were working but stopped, but it may have been the amp. Either way, i thought id check inside the boxes, and was quite shocked at the white fluffy stuff on the drivers. I thought it was the heavy dampening material as its quite flakey. There is no air conditioning at home so its quite humid here in summer, being a sub tropical climate in Australia.


I wiped and scraped some of it off, my hand was grey lol afterwards. There is some tiny rust spots. Also the old speaker gaskets have worn, so maybe air made it in that way or via the terminals.

Any ideas, my brother and another Aussie recommended a light rub with MX3 anti-corrosion, anti-moisture lube.

I can check the box internal seals also to make it more airtight or desiccant (little), PVA glue to seal the box joints or silicone?


https://imgur.com/dMth6bL

back of woofer
https://imgur.com/Sz2FC9u


Thanks
Sam

[Lawrence001]

I've seen it on a few speakers I don't think it's anything to worry about just some sort of oxidisation of the metal used. I suspect the amp is the issue can you find another to try to see if they work before doing anything too drastic to the speakers?

[walpurgis]

I have also seen this kind of corrosion. I believe it's caused by moisture retention in the cabinets, I'd suggest drying them out with the drive units removed. I'd not use anything oil based on the drivers, it can affect adhesives, just a clean/rub-down of affected areas and a thin brush painted coat of matt acrylic clear lacquer, that should help. Treating the cabinet exteriors with light Danish Oil may help reduce absorption of atmospheric moisture.

[MaccaAu]

I've seen it on a few speakers I don't think it's anything to worry about just some sort of oxidisation of the metal used. I suspect the amp is the issue can you find another to try to see if they work before doing anything too drastic to the speakers?

Thank you for the reply Lawrence. It has a little rust spot here and there on the bass driver. The woofers had a rubbing sound, when gently moved from the edges but rotating seemed to help, so maybe dust build up or from little use. I tested them with the multimeter and they registered ohms. It could be also the crossovers as i put new caps in and used at the time silver solder, so possible viabrations did something there also, so will check everything.


I have also seen this kind of corrosion. I believe it's caused by moisture retention in the cabinets, I'd suggest drying them out with the drive units removed. I'd not use anything oil based on the drivers, it can affect adhesives, just a clean/rub-down of affected areas and a thin brush painted coat of matt acrylic clear lacquer, that should help. Treating the cabinet exteriors with light Danish Oil may help reduce absorption of atmospheric moisture.

Thank you for the reply Geoff. That is good you and Lawrence have seen it before. The Aussie from another forum, also had KEFs similar to the Celestions. The drivers are out and crossovers of the cabinet, in a box. I plan to seal the edges inside the cabinet and new gaskets on the speaker drivers in hope to make it more air tight. I did put some stain on the cabinet exteriors. Thanks, I will look for a matt acrylic clear lacquer at the hardware chain we have out here, and check the crossover in case some of my solder work isnt up to scratch as that was done a few years ago now.