Yamana NS-690 how to remove gray dots?

[Pleyades]

Hello guys I've just recently got a pair of Yamaha NS-690 and I've started cleaning them, but I noticed some weird gray dots, I tried to clean them with alcohol, vinegar and acetone without success, I've started to think there are some kind of rust but the speaker basket looks like aluminum. how can I remove those weir dots from the speakers?

 

[avionic]

Those gray dots are aluminum oxidation pits.. Note the oxidated fasteners as well. I Had one with the same thing at one time on a NS-1000 tweeter. I very carefully bead blasted it.

 

[avionic]

This tweeter looked similar to yours..


After bead blasting...It looks like this.

 

[avionic]

Welcome aboard BTW..

 

[Pleyades]

Those gray dots are aluminum oxidation pits.. Note the oxidated fasteners as well. I Had one with the same thing at one time on a NS-1000 tweeter. I very carefully bead blasted it.

Thank you very much @avionic I've just took apart the whole twitter and the mids carefully yesterday and bring the face plates to a local guy who has a sandblast workshop and the result was very nice!

 

[avionic]

Looks like he did a great job.

 

[avionic]

Hopefully you can get them back together..

 

[avionic]

Looks like you had the woofers blasted as well.

 

[avionic]

Did you get them back together ?

 

[Pleyades]

Did you get them back together ?

I've been pretty busy these days , but today I've spent some time to get the tweeters and middle ranges back together

 

[avionic]

Looks good..

 

[gizzyman47]

I just leave the grills on...out of sight, out of mind!
Oh, Welcome!

 

[Seventy7]

I need to start on my 690's... I am sooo glad you posted pics! t's inspiring! Welcome aboard!!