Corrosion on speaker

[ficelles]

A Nomad I bought recently has the dreaded white corrosion (zinc hydroxide) on the pressed steel speaker frame... any tips for cleaning it without messing up the cone?

 

[electric mayhem]

Chemically speaking maybe lye? Or ammonia? Not sure about that on a frame of an otherwise good driver and I wouldn't be the guinea pig.

I picked up a Bassman combo with a 15" celestion bass driver. The "bottom edge" metal is very corroded and 2 things come to mind. Minor amount of sanding in the presence of an active shop vac or tape it off and spray some rust reformer on it. No one is going to see it so my only interest is stopping the oxidation.

But while rust reformer works on iron oxide, idk about zinc hydroxide.

 

[bandit2013]

It may be better just to replace them (depends on the cost to refurbish the steel). If the galvanized steel has been compromised due to excess moisture. It may be a form of zinc hydroxide or zinc oxide too many websites are involved with its uses rather than the remedy to prevent or remove it. Look up "white rust" instead as a more common term. There are a few methods used to remove it. the issue is removal requires a wire brush or sanding. Not good method since there is a magnet attached to the basket. You can tape up the magnet but will be hard to prevent any debris on the spider or cone. It probably is not all that bad but good luck with that. I hope you find a fix. If there was an easy way to refurbish it, it was not apparent in the search for a fix.

 

[ficelles]

I already dropped a replacement speaker in (Eminence Redcoat) but am going to try and get the white corrosion off and save the C90, I have read that white vinegar can remove it so will give that a try.

 

[bandit2013]

Based on the appearance of the sheet metal basket surface, it looks more like it is electroplated if it is zinc. Not sure if that is true or not. Celestion does not have much information on their website on their process. If it is electroplated, the zinc layer will be very thin. I always thought they were painted like the V30.