Can we talk about "DOPE" here

[gamalot]

Now I know there are probably a few experts among us but I'm talking about the dope used on the accordion surrounds of Altec 414s and 416 woofers.

I'm getting a fair ammount of flames over at the LH site for stating the goop I have seen is a black tarry substance that appears to never dry and can be affected by heat or direct sunlight and drip or pool.

Others there claim what GPA uses is a clear liquid that just looks black.

The few times I have dealt with this stuff it sure looks very dark to me so what gives here. Does anyone know the real story about the stuff and what color it is when in the can or jar from where it comes?

I have a few fresh recones here from GPA and it sure looks dark to me but I never saw it in raw form.

Thanks
Gary

[GM]

Well, my '50s era 515Bs goop that 'pools' at the bottom during the summer heat looks chocolate brown to me on the surrounds and when scooped up looks like a very dark molasses. Knowing that the surrounds are a dark (deep chocolate or faded black? Can't remember it's been so long since I've seen a period correct factory re-cone kit), starched open weave cloth it seems reasonable to me that a clear solvent based goop would mirror the color of the material and leach out any dye/starch over time that combined with acting as an air-borne particulate 'magnet' would be turned 'dirty' in color.

GM

[bowtie427ss]

It starts out clear, i think it picks up some of the dye from the linen surround over time.

Just my .02.................

[Audio_by_Goodwill]

Originally posted by bfish:
While all the above is true, I'd like to complicate things a bit.

<font size="2" face="Verdana, Helvetica, sans-serif">No, not you!

[gamalot]

"Gary, out of curiousity I found your LH thread. Just my 2 cents, but I'd let that one die in the dirt where it lays."

Yep! Dead and done with that AH!

All I can say is I did once see a jar of said dope straight from Altec many years ago and it was a dark molases color. A few of the oldies I have purchased had the stuff pooled at the bottom and removal was a PITA with MEK and a hair dryer and the removed substance sure did appear just like tar.

Even the fresh woofs from GPA look as though the stuff is dark yet I'm not about to start picking at nice new recones to get the answer for myself.

Thanks to all.

Gary

[cclark65]

The stuff that ran off my model 6 midrange drivers is a very light yellowish color to it. I haven't checked out the 604's surround by trying ti pick any off, but it appears to be light also.

However, a repair that was done on a speaker a while back by a local speaker shop came back with almost black looking stuff.

[bfish]

Originally posted by Audio_by_Goodwill:
No, not you!

<font size="2" face="Verdana, Helvetica, sans-serif">Yesme. I believe anything involving human behavior is inherently chaotic, except, of course, things involving human behavior (rinse, replace fuse, repeat).

Poor old Gary, accustomed to casual conversations here among friends that are almost expected to go OT at some point, merely got caught up in the chaos.

OT trivia-In all the various (speaker surround) dopes (non-human) I've encountered, I only see one commonality, their reason for use (sealing the surround, damping rim resonance, and, in the case of paper surrounds, preserving compliance). Other than that, applying any single property to all is foolish. Some are latex based, and DO permanently dry. The solvent-thinned types have varying degrees of thermo-plasticity, for example, you could use a hair dryer until the house burns down on some with absolutely no effect other than burning down the house.

Hmmm...now there's a good name for a prospective new member...speaker dope...

Anybody got a light? [img]graemlins/handcuffs.gif[/img]

Added;
O-OT; Zilchping...
Good painters tape (for auto body) is green, the homecenter blue is for easy-release, GP use.

<font color="#FFFFFF" size="1">[ May 22, 2008 08:15 PM: Message edited by: bfish ]</font>

[valhallax]

when i got my old 210 cabs, tho pooling on the bottom of the speaker mounting baffle was black...in fact, the old speaker gaskets, the previous owner, left on the baffles were fairly well glued near the bottom

[Russnohio]

Hi Gary. The stuff I got from GPA a year or two ago looks like this.....

[bfish]

Final (I swear) afterthought.

Eventually, the Q will arise, "why couldn't things be simple, and there just be one dope used forever?..."

Two reasons; advances in technology, and equally, govt regulation. Polymer mfrs have strict regs on VOCs, flammability, toxicity, etc, not only on the products they make, but the processes involved in making them. Inability to show a glowing MSDS for a product can send insurance through the roof. Every time a new regulation makes an existing product less acceptable means starting over. It's the price we pay.