Stiffening Paper woofer cones.

[kingfootga]

I found an old pair of paper 12" woofers that sound great, but the cone is bending a lot and distorting the sound quite a bit. I am on a budget and am wondering if there is any way to stiffen up the cones. Could a thin layer of epoxy be put on top? What about epoxing little strips of cardboard (like from a legal pad) to the cone? Any suggestions would be appreciated. Thanks.

[Dustin Haug]

Not sure if I'd try this unless you figure you have nothing to lose. Check this link.

http://www.t-linespeakers.org/design/tweeks.html

[mrfeedback]

Hello Kingfoota,
I have used standard white PVA woodworking glue to treat the 10" cones on a friends guitar amp combo.
I thinned the initial coats with water so that it could soak/absorb into the cone and applied several more coats over a few hours.
This gave a very stiff cone, and nicely dead (quiet).
This worked very nicely in the guitar amp, with clean sounds and just the right amount of bite.

Hope this helps,
Regards, Eric.

[planet10]

Originally posted by mrfeedback
Hello Kingfoota,
I have used standard white PVA woodworking glue to

The puzzlecoat mentioned on my tweeks page is a PVA based glue. I have been using this stuff for 25 years and it can produce excellent results -- don't go overboard.

dave

[logicsound]

Please, use a thin epoxy glue and coat the underside of the cone, do not glue too many things to the cone or it will become too heavy and loose it efficiency and it will drop the frequency response. Find a THIN epoxy from a hardware store and it will last a few more years, also check that the bottom suspension is not warped or damaged. Good luck!

[mrfeedback]

Hiya kingfootga, PVA smells, feels, looks, (tastes ?) nicer than epoxy IMHO.
Organic-ish is different to MAN-ufactured - get the drift ?
Dave is correct - be careful to not go overboard.
IMHO - woofers can well benefit from just the right degree stiffening, damping and HF rolloff.

Regards, Eric.

[FlMike]

i have used a 50/50 mix of white glue and water several times with good results and have also used "the wet look" from parts express wich seems to do ok also.
the wet look is " a new generation of high gloss polymers formulated especially for the the speaker industry" "provides a protective coat of armor for you paper cone speakers"

i have used this on some early advents and it seemed to work ok but the glue water mixture also seems to work just as well and cost alot less.


mike

[mrfeedback]

Thanks FlMike.
And after this a coat of liquid latex can give additional nice damping characteristic too.
Easily and cheaply available.

Regards, Eric.

[leroy]

I used three layers of transparent floor-lacquer once on a 12" subwoofer and it certainly benefitted from it. A major advantage is there's hardly any weight added to the cone, and it won't hurt your wallet.

leroy

[dex-rex]

Kingfootga,
I tried PVA,linear polyurethane...but epoxy works best for me!Epoxy coating will give the best ratio of weight to stiffness,whithout doubt.You can even add some glass or carbon fibres for ultimate rigid cone.I`ll recommend applying thin epoxy coating on both cone sides resulting in stiff "sandwich"membrane.Downside is that you MUST protect epoxy exposed to UV,meaning sunlight, with protective coating(e.g.two component polyurethane varnish or paint).How deep epoxy will penetrate into paper depends on its consistensy(viscosity) and I`m using West system 105 resin and 205 hardener with very good results www.westsystem.com .PVA is very good if you want broadband spectrum quality,sounding similar to polypropylene cones,but for the same stiffness PVA treated cone is heavier.PVA is much easier to work with.
Best regards