Speaker Refoaming....Advice Please.

[Lamf77]

Thought someone here would know a wee bit about speaker repair. These are woofers from my Dahquist DQM-9 speakers. Son ripped the foam years ago (like 25)...now gonna attempt faom replacement. I got a kit from Simply Speakers. I followed their YouTube video to a tee so far. I got all the old foam off...cleaned the basket. However the whitish ring of old glue is very resistent. Used a razor blade and exacto to get off the foam...but does not seem to work on the glue. Read solvents like Goo Gone can be used...but was wondering if the old glue can still stay? Any advice or help is really appreciated...thanks!

[mozz]

I don't think goo gone will touch that. Music electronics forum is down but diyaudio.com might have answers for you.

[Tiga]

I'd be afraid of damaging the cone with solvents. Is the old glue fairly smooth? Just wondering if you could glue the new surround right over top of it.

[andrewsrea]

Goo Gone is petroleum based and leaves residue, especially on cloth and paper.

I'd suggest working the frame with a heat gun and small chisel or screwdriver. A quick working with wire wheel on a Dremel tool might work as well, but watch out for fragments of wire being attracted to the magnet.

I've done re-coning and re-foaming before. The glues involved do not require perfection, just consistent coverage. The part on re-foaming to be deliberate, is ensuring the speaker is level to gravity so the coil former will move in the magnet gap without rubbing.

[Lamf77]

Goo Gone is petroleum based and leaves residue, especially on cloth and paper.

I'd suggest working the frame with a heat gun and small chisel or screwdriver. A quick working with wire wheel on a Dremel tool might work as well, but watch out for fragments of wire being attracted to the magnet.

I've done re-coning and re-foaming before. The glues involved do not require perfection, just consistent coverage. The part on re-foaming to be deliberate, is ensuring the speaker is level to gravity so the coil former will move in the magnet gap without rubbing.

The company that sold the foam and glue has a pretty good video. Of course the guy who does it has probably done about a thousand speakers. He shows how you want to push down and make sure it doesn't rub when securing it to the frame. He just uses alcohol to get off the old glue but that's not working. In the comment section on the video he suggests using acetone or lacquer thinner?. I might just make sure that the glue on the speaker cone is somewhat smooth and just try gluing over it. Even if I use a razor blade which is obviously extremely sharp, it's very difficult to get it off. Thanks!

[Tiga]

I've reformed a fair number of speakers - I use Aileens Tacky Glue with success. I've had mixed results with trying to center the cone by hand so I typically cut the dust cap around, leaving a small piece uncut so I can pull the cap back like a flap. I then shim the voice coils and glue the surrounds in place. Once they are set up I glue the dust caps back (sometimes I replace these too). I've had 100% success with shimming the voice coil.

[Lamf77]

I've reformed a fair number of speakers - I use Aileens Tacky Glue with success. I've had mixed results with trying to center the cone by hand so I typically cut the dust cap around, leaving a small piece uncut so I can pull the cap back like a flap. I then shim the voice coils and glue the surrounds in place. Once they are set up I glue the dust caps back (sometimes I replace these too). I've had 100% success with shimming the voice coil.

I have to research the shim deal. Video says it is not needed. I have also seen people use a tone generator of some kind to help align...not sure how that would work. What do you use to shim? And is it just a matter of doing it all around the thing in the center?

[andrewsrea]

In the comment section on the video he suggests using acetone or lacquer thinner?.

Lacquer thinner is very powerful. Wear gloves, a breather and have ventilation (I prefer painting in lacquer and have about 100 to 200 hours of experience). It can be absorbed into bare skin.

Here is my thoughts on how much glue removal is 'good enough':

- If you are at a point where the remaining glue is resistant to extreme deliberate methods, if is highly unlikely to ever come off with the speaker in use.
- Expansion and contraction weakens glue. A couple of rounds with a heat gun will get most of the residual glue off.
- Adhesives (and solder) work best with rough surfaces, so scrapes in the surround frame and a bit of petrified glue will provide really strong adhesion over a smooth surface.
- A deliberate glue application will fill voids left by artifacts on the frame (not too little, not too runny).