Any ideas on how to best deal with surround ooze? I have a pair of Altec 414Zs that are in absolutely excellent condition except that they sat in an attic for the last decade or two and the coating on the surround ran. It glued the paper gasket to the cabinet and tore as I removed the woofer. The gasket is replaceable, but does anyone have a good fix for the excess goo? I know this is a common problem... but not one I've had before.
Widget
Try and heat it up slowly and you can use a Q-tip to remove excess goop(modified rubber cement is what I heard is used).
Maybe others have different ideas, that is what I used in the past to bring the surrounds back to life and look shiny again.
Don't let the heat get too hot as it might catch fire!!!
Ron
JBL Pro for home use!
M.E.K. is what the reconer at G.P.A. uses. and that is what I use since he shared the info with me.
Thanks for the tip. I'll get some M.E.K.
Widget
Widget, as you know this happens a lot with the doped Altec surrounds. The stuff is thermoplastic, and my theory has been that it migrates mostly when it gets warm.
As a vintage audio reseller taught me, warming it up and scooping out the excess is the thing to do. I use a hair dryer to warm it up and a small rounded dowel to scoop the material. Looks disturbed at first, but the material reflows and removes the evidence of your repair.
Leaving it alone is not a good option, as the goop immobilizes the surround and the cone can tear at that point. I had four 414Zs that had done this.
Well... that's two votes for heat. I was nervous about trying heat, why go organic when you can use carcinogens instead.
Widget
With the M.E.K. if you use too much it will activate the glue holding the surround down and lift it. I have used the heat method many times and it works good
i've used heat as well to remove excess, much in the same way Steve described -- except instead of a dowel, i used the rounded edge of a crab fork
Widget, let us know how the heat thing (vs. MEK) goes. I've got several
of these I'm going to need to "correct" a bit more than the one in your
photo(appears someone got a bit enthusiastic in "goo" application).
... returning some nice, but empty, Avalon/Carmel cabs to service.
-grumpy
M.E.K. is used to thin the goop for application to surround. I have removed excess on a few 15",s with a tooth pick and smoothed it over with a soldering flux brush dipped in M.E.K.Originally Posted by Mr. Widget
Well... that's two votes for heat. I was nervous about trying heat, why go organic when you can use carcinogens instead.
Widget
By the way the flux brush application is the way G.P.A. applies the goop to the surround's after the goop is thinned with M.E.K
I would go very easy with the heat!!! Just enought to warm the goop but not enought to cause any harm to the accordian surround.
Do you (or anyone else) have T/S parameters for those drivers, Mr. Widget?
Have you measured them, perhaps?
Or, if not, would you do that, please?
These are very popular woofers, yet nobody seems to know very much about them.... :dont-know
No.
No.
Maybe. If I decide to keep them I will, and I'd be happy to share the data. They were given to me by a friend and I haven't decided what to do with them. I still haven't cleaned up their surrounds, in fact other than applying signal to them to see if they make noise, I haven't touched them.
Widget
FWIW, I ran two over-gooped (from what I've seen) 414z's through WT-2
and it seems I should indeed un-goop them and remeasure (significant
differences are shown):
Re: 11.5 ohms
Fs: 40, 49.2, 45 Hz
Qes: .29, .36, ...
Qms: 3.51, 2.46, 1.0
Qts: .267, .316, .3
Le: 2.3 mH
Vas: 210, 130, 150 l (delta mass method)
BL: 20, 20, 19.5
Mms: 41g
I've added info for a third unit.
-grumpy
Last edited by grumpy; 03-01-2008 at 09:40 PM. Reason: added third unit
Thanks, Widget and Grumpy.
That certainly illustrates the problem working with or designing around these vintage drivers, no matter how "good" they are (or were.)
If there were some specs available, we could at least assess the condition of individual units against those.
The situation is much the same with 416A/Z.
I suppose one option is to have them rebuilt "as new" and work from there.... :dont-know
Yep, most of the "hard" T/S parameters seem to agree (Re, BL, Mms, Le),
it's the suspension-related stuff that varies (no surprise). Testing "freshies"
would give us a reasonable baseline. ... I see sean19's recent post shows
an Altec spec'd Fs of 30Hz for a 414-type unit.
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