I purchased a 12" woofer

[Giorgio AR]

I just bought a 12 "woofer to keep as a spare.
Purchased on the popular auction site, virtually blind!
As can be seen from the 2 photos in the auction, the woofer has corrosion to the basket, a fold on the paper cone and I do not know the electrical condition of the woofer! (The seller did not declare if working or resistance values of the coil).

On the auction site it was referred to as an "AR3ai" woofer.
In my opinion, it could belong to an AR3a improved (this justifies the final i of the code), so it should be a woofer produced from '74, perfectly in line with my three pairs of speakers of the same year (AR3a - AR3a improved and AR LST !!!).
I will be able to date the woofer in a few days when it arrives at my house and I hope to confirm the contemporaneity with my speakers.
I will send more and better photos of the woofer at the arrival of the same, as well as the documented phases of its restoration.
It will have to return to be perfectly functional and aesthetically perfect as when assembled by mom Acoustic Research.
It seems like a great challenge.

[Giorgio AR]

Arrivato il woofer da 12", nelle prime due foto si vede lo stato del woofer all'arrivo. Foto
a seguire dopo la rimozione di schiuma, colla, detriti, peli ecc.
Si allega anche la foto della data.
Ora devo eliminare le tracce di ossidazione dal cestello con rimozione chimica della "ruggine".

 

 

[Giorgio AR]

 

Remove the glue around the holes in the basket, the oxidation still remains to be removed ...

 

[Giorgio AR]

Eliminata la ruggine, ho usato lana di metallo e converter chimico (fosfato), non ho usato carta abrasiva per non lasciare segni sul telaio del cestello, è molto visibile c'è molta differenza tra prima e dopo il lavoro di disossidazione.

Esteticamente il cestello in metallo è tornato in ottime condizioni, la ruggine e le tracce di ossido sono scomparse, l'aspetto ora è quasi uguale a quello nuovo.

 

 

[Giorgio AR]

1 hour ago, Giorgio AR said:

Eliminated the rust, I used metal wool and chemical converter (phosphate), I did not use abrasive paper to leave no marks on the basket frame,It is very visible  there is much difference between before and after the deoxidizing work.

Aesthetically the metal basket has returned in excellent shape, the rust and the traces of oxide have disappeared, the appearance is now almost the same as the new one.

 

 

 

 

Clean also the protective meshes from the glue and debris and dirt, I'm sorry for the color of these photos, but has disturbed the sun, now just missing the foam from Larry (it will take about a month before the shipment arrives at my home in Italy), then we will see a very good 12 "woofer ready to use.

[ra.ra]

2 hours ago, Giorgio AR said:

...it will take about a month before the shipment arrives....

Your clean-up efforts on the backside of these woofers look really great - - - now you've still got some time to work on the front sides before the new foams arrive.  For me, it is an important step to make your best effort to improve the appearance from the front side as well. A recent AR-6 project shown here for example.

[Giorgio AR]

15 hours ago, ra.ra said:

...

 

Thanks for the encouragement, in fact on the cone anteriorly there are three small white points to be removed (I have already mechanically removed the bulk of the white), these will be darkened by the graphite of a pencil, the aesthetic effect will be uniform again.
It is also to be painted in black smoke the frame outside the ring in masonite (the black smoke is prepared by me combining the ash of the wood stove with a black vinyl color, the effect you'll see as soon as I publish the photos of the work performed).
If I may I would like to give advice on inserting the woofer screws after refoaming:
On the outer edge of the foam it is not necessary to drill it to insert the screws, just oil the head of the screw slightly, this will flow by screwing on the foam without deforming the ring of the foam itself.
The subsequent removal of the screws will show the foam only a little crushed where the screw locks, the ring will be perfect, without cuts or twists.
 

[Giorgio AR]

4 hours ago, Giorgio AR said:

Thanks for the encouragement, in fact on the cone anteriorly there are three small white points to be removed (I have already mechanically removed the bulk of the white), these will be darkened by the graphite of a pencil, the aesthetic effect will be uniform again.
It is also to be painted in black smoke the frame outside the ring in masonite (the black smoke is prepared by me combining the ash of the wood stove with a black vinyl color, the effect you'll see as soon as I publish the photos of the work performed).
If I may I would like to give advice on inserting the woofer screws after refoaming:
On the outer edge of the foam it is not necessary to drill it to insert the screws, just oil the head of the screw slightly, this will flow by screwing on the foam without deforming the ring of the foam itself.
The subsequent removal of the screws will show the foam only a little crushed where the screw locks, the ring will be perfect, without cuts or twists.
 

Painted the frame around the masonite

[Pete B]

"Eliminated the rust, I used metal wool and chemical converter (phosphate), "

Excellent work, is this, naval jelly the type of product that you used? 

http://www.loctiteproducts.com/p/s_trmt_naval/overview/Loctite-Naval-Jelly-Rust-Dissolver.htm

[Giorgio AR]

Hi Pete, I do not have the product you indicated to me, I used a generic product (there are several types) containing more than 25% phosphoric acid, applied with a brush (protecting the cone below with a nylon sheet), leaving act for about 30 minutes and brush with the brush in the areas of greater oxide, after removing the product with various steps with a sponge and distilled H2O.
At the end the effect is visible in the photos, almost complete disappearance of the rust, a light protective layer left on the metal by the oxidation of the product during the drying, not rust return even without protective painting.
In this case (not working dry), it also causes the annoying iron powder that settles on the magnet and frame, difficult to remove. Remember that in order to have a renewed and natural effect of the frame, it is better to use steel straw or brush instead of abrasive paper.

If you use the abrasive paper, the metal of the frame will have a satin appearance (more or less fine depending on the grain used), using the metal straw, the metal of the frame returns to its natural appearance, devoid of the original treatment in Nickel ( that after the treatment with phosphoric acid it becomes opaque gray from glossy as it was before -Check the sequence of photos below and see how the nickel coating changes -).
I hope I have made you understand the process (around 1.30 hours of work)

[Giorgio AR]

11 hours ago, Pete B said:

"Eliminated the rust, I used metal wool and chemical converter (phosphate), "

Excellent work, is this, naval jelly the type of product that you used? 

http://www.loctiteproducts.com/p/s_trmt_naval/overview/Loctite-Naval-Jelly-Rust-Dissolver.htm

Here are the photos of the product to eliminate rust