Which woofers to replace the ones in my Sonus Faber speakers?

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#61
Progger58 said:
So I have just bought new surrounds.
A month or so to receive them...
Meanwhile, what's the best glue I should buy to fix them?
The easiest to use, if possible. 🙂
Click to expand...
I used a fast vinyl glue like Bindan that's suitable to glue leather, paper, felt, etc., to replace the foam surround of my Audax woofer.
Glue the surround to the chassis, apply the glue to the membrane and then connect a 1.5V battery to push the cone forward. Press lightly the surround against the cone around the whole circumference till the glue is dry. Pay attention that the surround remains concentric to the cone.
 
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#64
Turbowatch2 said:
Reconing is a very usual task with PA drivers, but only changing the surround is a much more delicate job with small high end HIFI chassis.
You should use some glue specified by the replacement surround supplier. This should be your first source of information.

An even more interesting question is how to clean up the driver for installation of a new surround, without destroying anything. If this is not made in a perfect way, the whole operation will not work out well. For 4 driver of this size, an hour each, just for cleaning, would be my estimate. With clean, this means absolutely nothing left, no parts of the surround, no spot of glue! While cleaning, be sure to prevent any debris enter the air gap through the open phase plug.
The contact patch to the aluminum basket is quite easy to do, as you can mechanically scrape off anything, but the cone is more diffilcult. If you just rip off the surround, you will harm the paper, because the glue is stronger than paper and foam.
My first try would allways be with a heat gun, careful of course, so you don't ignite the cone. If you are lucky the glue will get liquid and leave a nice surface for a new connection. If that doesn't work you may try a solvent like acetone or concentrated alcohol. The glue on the basket may not be the same as the one used at the cone.
Now glue. This is an endless story. Today even airplanes are glued together.
Concerning glue all options are on the table, depending on the new surrounds material.
If it is sensitive to solvent, only 2-component or water based /hardening are an option. Usual water based will only work if one sides is porous and lets water evaborate.
Contact glue is nothing you should use if you try positioning by hand, as you can not correct anything. Most are solvent based anyway.
Non foaming PU glue may be good option, but hard to pick the right one and get small amounts.
There are a a lot of specilized glues around, like the ones made for car wind screens, which dry by taking water from the air.

I usually take off the dust cab, yours don't have one. If you can place a piece of flexible plastic in the air gap, this centers the voice coil. I would use this option, otherwise you run into the problem of a scraping voice coil quite sure. This problem is called rub and buzz.
Even if you have the voicecoil fixated, don't put any tension on the new surround while glueing it. The only way to repair such a problem later, is repeating the whole process with a new part.
If you are new to technical glueing, the user manual should be followed. If it say's let dry for 24 hours, don't do "only a short test" after an hour.
Click to expand...

When you say "If you can place a piece of flexible plastic in the air gap, this centers the voice coil", I guess you meant something like this? 👇

WOOFER Preparation 1.jpg


This white paper piece was inserted in the air gap. It wouldn't be the definitive piece I intended to use, of course. Just to exemplify.
 
#65
Yes, exactly. Just a little thicker and not overlapping.

The vendor of the surround deliveres super glue (Isocyanat). This should work, but is a one time fix and not easy to handle, as it may tack the same moment the parts make contact. You got to be quick and precise, get it right on the first try.
 
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