Cloth surrounds

[dynaco_dan]

Wouldn't it be funny if we somhow found out that Permatex (or something very similar) is what was used originally to seal these classic speaker's cloth surrounds?

It behaves pretty much the same with respect to its tackiness.

Hi Carl;

You may very well be correct.

I would think that the original compound was probably another compound, used commercally, and not good for anyones health and was discontinued.

I didn't see any safety gear in those photos of person's applying the compound.

It certainly possibly wasn't the first such case, as I worked with asbestos, un-protected, in the heating industry for decades.

My first employer for 9 years, did not have ANY safety practices setup.

[dynaco_dan]

Hi Carl;

You may very well be correct.

I would think that the original compound was probably another compound, used commercally, and not good for anyones health and was discontinued.

I didn't see any safety gear in those photos of person's applying the compound.

It certainly possibly wasn't the first such case, as I worked with asbestos, un-protected, in the heating industry for decades.

My first employer for 9 years, did not have ANY safety practices setup.

Hi again;

I recently wrote in the Advent forum regarding using, 3M #847 Rubber and Gasket Adhesive, for re-foaming surrounds.

It has been used here in Vancouver speaker service departments for many years for the purpose of bonding the foam surrounds to the speaker frames successfully.

This compound does not specify that it remains sticky, or not, as in non-hardening, the same as the Permatex High Tack Gasket Sealant does.

I wonder if this might also be useful for re-coating the cloth surrounds. MMMMMM

I believe it was, Roy, that wrote, Permatex, appeared not to be suitable for re-foaming projects.

The 3M is about 50% more expensive than the Permatex.

$60.00 CDN for 32 oz of 3M and $20.00 CDN for 16 oz Permatex, both non-mailable of course.

[Guest molecules]

Found some permatex on Ebay 1.75 ounces for about $7.00 delivered. I used it on a KLH 20 woofer, it works well, but is an ugly yellow color. Also do small sections because it dries quickly and I think I have a little too much on it.

[RoyC]

Found some permatex on Ebay 1.75 ounces for about $7.00 delivered. I used it on a KLH 20 woofer, it works well, but is an ugly yellow color. Also do small sections because it dries quickly and I think I have a little too much on it.

I think you used the wrong stuff...4 ounces of the Permatex High Tack Gasket Sealer costs around $5. It is reddish in color, and does not really "dry", as it remains sticky. It is easily thinned with lacquer thinner, and should be used very sparingly. Permatex manufactures many products.

Roy

[dick]

As a minor note, I found that NAPA auto supply stores carry the Permatex #80062 but with their own numbering on it -- there's a Permatex label, but a NAPA number. They cross-referenced their number for me and it checked out. I could not find any of the Permatex #80062 by calling local stores (western Massachusetts) but readily found it when a NAPA clerk bothered to check it out for me.

[oldguide]

Did you try Ace hardware, Checker AP, Pep Boys, Home Depot, etc. I have seen it in all three here in the Midwest. I agree with Roy the stuff you received over eBay is NOT Permatex.

Thanks again to Roy and the other folks who wrote the guide for putting me on to this. What is it the old ad used to say, "Accept no substitutes."

[ARRAY]

Hello, I couldn't help but notice this thread while responding to a private message. I haven't mentioned this before on ClassicSpeaker pages but I supply technicians with damping compound, the real stuff used in actual driver manufacturing. I will be posting an ad in the "For Sale" section of this website within the new year for anyone who's interested.

[Dormie]

permatex is avail from carquest auto parts in canada/usa,

www.carquest.com,

diluting very lightly with acetone,

about one drop per speaker quantity,

thins out the liquid,

this stops it from being stringy,

full strength you have string everytime your brush touches anything,

I just did some KLH model 17s,

thanks for everyone's contributions

[dynaco_dan]

permatex is avail from carquest auto parts in canada/usa,

www.carquest.com,

Hi there;

I may have mentioned this earlier but it bears repeating.

In Vancouver the cans I bought of the 3M and Permatex products are specially handled and labeled.

They are treated as explosives or similar.

They cannot go through the regular mailing process but require special trucking transportion.

The seller on eBay may have broken US Federal Postal laws, etc, in mailing the product to a member.

In Canada we pay a special trucking surcharge under the Dangerous Goods Act, pennies on the dollar but a surcharge nevertheless.

You will need to buy it locally and pick it up in person or not at all.

Vern

[Carlspeak]

Hi Vern. Nice to see you back. Haven't 'heard' much from you lately.

[RoyC]

Hi Guys,

I recently re-tested (out of cabinet) a few woofers treated with Permatex last year, and it appears that fs has risen on the average of 3 to 4 hz. The Permatex has lost its tacky nature, and seems to have stiffened a bit. While still better than anything else I have used in the past, the rise in fs is a little disconcerting.

Carl, I was wondering if you still have any of your test woofers around to check out.

Roy

[Mexicomike]

Hi Guys,

I recently re-tested (out of cabinet) a few woofers treated with Permatex last year, and it appears that fs has risen on the average of 3 to 4 hz. The Permatex has lost its tacky nature, and seems to have stiffened a bit. While still better than anything else I have used in the past, the rise in fs is a little disconcerting.

Carl, I was wondering if you still have any of your test woofers around to check out.

Roy

Has anyone tried 3M weatherstrip adhesive? It comes in black and yellow and seems as though it might be suitable for this purpose if thinned. I have never tried to thin it but I would expect that lacquer thinner or acetone would work. It's extremely flexible when dry and might be worth a look if that hasn't already been done. I believe that it will not further harden over time, at least based on how it acts when you try to remove weatherstripping that was attached using it.

[Carlspeak]

Hi Guys,

I recently re-tested (out of cabinet) a few woofers treated with Permatex last year, and it appears that fs has risen on the average of 3 to 4 hz. The Permatex has lost its tacky nature, and seems to have stiffened a bit. While still better than anything else I have used in the past, the rise in fs is a little disconcerting.

Carl, I was wondering if you still have any of your test woofers around to check out.

Roy

No, I don't Roy.

It may simply be that while we're striving to find someting like the 'original' sealant, even the original applied to the surrounds met the same fate you site above. I write this because if they did stiffen over time, it would explain why on many vintage cloth surround woofers we see numerous areas where light shines thru that resulted from the sealant hardening and falling out with flexure of the cloth during normal use.

[RoyC]

No, I don't Roy.

It may simply be that while we're striving to find someting like the 'original' sealant, even the original applied to the surrounds met the same fate you site above. I write this because if they did stiffen over time, it would explain why on many vintage cloth surround woofers we see numerous areas where light shines thru that resulted from the sealant hardening and falling out with flexure of the cloth during normal use.

Agreed...time probably takes its toll on any of the materials used as sealants, but this seemed a bit premature....So, after noticing the surrounds were more flexible after being at room temperature for awhile, I decided to run more measurements at different temperatures . Sure enough, the fs averaged 3.5 hz less at 80 degrees F than at 60F. The increase in fs since first applying the Permatex is not as great as I thought (maybe 1 to 2 hz). I first measured the woofers in my previous post soon after removing them from a very cool storage area.

Mike, I have not tried the glue you mentioned, but if it "dries" (even if it remains flexible) it is probably too thick. I am currently experimenting with some stuff that, like Permatex, is butyl rubber based. This material, however, remains very sticky, like the original butyl based material AR used. I am hoping it can be used on foam surrounds as well....stay tuned:-).

Roy

[Carlspeak]

I've also noticed when checking Fs numerous time during some spider softening experiments that Fs drops after extended cycling at relatively high power. I guess the extreme flexing sort of softens up the joints in the foam like my arthritis does in my hands in the morning after waking up

[Zilch]

I've also noticed when checking Fs numerous time during some spider softening experiments that Fs drops after extended cycling at relatively high power.

Parameter changes after high-power testing are common; they return to original after "resting."

[Carlspeak]

Zilch: "Parameter changes after high-power testing are common; they return to original after "resting."

Yup, I forgot to add that sentence in my last post. The Fs does go back up with rest.

[genek]

Mike, I have not tried the glue you mentioned, but if it "dries" (even if it remains flexible) it is probably too thick. I am currently experimenting with some stuff that, like Permatex, is butyl rubber based. This material, however, remains very sticky, like the original butyl based material AR used. I am hoping it can be used on foam surrounds as well....stay tuned:-).

I've never owned any speakers with cloth surrounds, but when I was a kid my father used to build his own speakers, and used a speaker doping solution manufactured by GC Electronics (reddish-colored product sort of like thinned contact cement that remained tacky forever). I remember trying some of it on an early-model foam surround woofer that had a tear in it and was destined for the trash anyway, and the solvent in the doping melted the foam on contact.

I suppose the obvious question raised by changes to surround coatings with age is, if the originals also changed as speculated, did the original manufacturers allow for this in their designs, and was there a typical "break-in" aging period and a projected "end of life" point when they would recommend replacement to customers inquiring about service to old products?

[RoyC]

I've never owned any speakers with cloth surrounds, but when I was a kid my father used to build his own speakers, and used a speaker doping solution manufactured by GC Electronics (reddish-colored product sort of like thinned contact cement that remained tacky forever). I remember trying some of it on an early-model foam surround woofer that had a tear in it and was destined for the trash anyway, and the solvent in the doping melted the foam on contact.

I suppose the obvious question raised by changes to surround coatings with age is, if the originals also changed as speculated, did the original manufacturers allow for this in their designs, and was there a typical "break-in" aging period and a projected "end of life" point when they would recommend replacement to customers inquiring about service to old products?

I was wondering about that as well. I'm guessing AR really had no idea how long such things would last, or that we would be dissecting and using them 40 years later. The company, however, was apparently confident enough in their materials to offer and make good on a very liberal warranty policy. We have seen AR's QC testing mentioned, but never any mention of "break-in" periods.

Attached is a pic showing some of my experimental butyl compound applied to a test foam surround. The surround appears to be OK so far, but when I was experimenting with Permatex I found some foam surrounds react differently than others to solvents. I have applied it to installed cloth surround woofers, and it has not negatively affected compliance or performance, and it remains extremely tacky. I am becoming increasingly convinced that (depending on viscosity) it is very close to the material AR used on surrounds, cones, and early tweeter suspensions.

Roy

[genek]

Attached is a pic showing some of my experimental butyl compound applied to a test foam surround. The surround appears to be OK so far, but when I was experimenting with Permatex I found some foam surrounds react differently than others to solvents. I have applied it to installed cloth surround woofers, and it has not negatively affected compliance or performance, and it remains extremely tacky. I am becoming increasingly convinced that (depending on viscosity) it is very close to the material AR used on surrounds, cones, and early tweeter suspensions.

Is there any indication that AR doped foam surrounds? My 1975 2ax's had the removable velcro-retained grills and, naturally, I looked inside. The surrounds were dead matte in appearance and dry to the touch from day one.

[RoyC]

Is there any indication that AR doped foam surrounds? My 1975 2ax's had the removable velcro-retained grills and, naturally, I looked inside. The surrounds were dead matte in appearance and dry to the touch from day one.

Yes, they were treated (and very sticky) into the 70's sometime. Tom Tyson has posted info in the past about the butyl based stuff that was used.

Of course the necessity of treating replacement AR foam surrounds today is open to debate. The most common 12" surround, as well as the preferred JBL surrounds for the 8 and 10 inch woofers, are very compliant and relatively non-porous. A number of the generic replacement surrounds are more porous, and presumably could benefit from a sealant.

At the moment I'm just following up on a hunch regarding the duplication of an AR material, which I believe was used for a number of purposes.

Roy

[RoyC]

I am currently experimenting with some stuff that, like Permatex, is butyl rubber based. This material, however, remains very sticky, like the original butyl based material AR used. I am hoping it can be used on foam surrounds as well....stay tuned:-).

Roy

I resurrected this thread to provide an update on the surround sealant I have been experimenting with.

In short, I am quite convinced it is effective and safe for use on cloth surrounds. There have been no changes in any of the KLH or AR woofers I have treated over the past 6 months. In every case fs has remained constant, and the surround has remained sealed. The stuff remains very tacky with no signs of "drying". Best of all, it is thin enough not to negatively effect a woofer that may not need re-treatment....so, at worst, performance should be unchanged.

It is chemically similar to Permatex gasket sealant (as well as the original AR sealant), but it is thinner, and remains much more tacky. It, like Permatex, is solvent based (toluene) and should be applied in a ventilated area. Although I have had some success, I cannot recommend it for use on foam surrounds, as the solvent can have a negative impact on some types of foam.

If anyone would like to give it a try, PM me...

Roy

[Carlspeak]

I have a funny story to share. I recently coated a pair of older style AR3 woofers with Roy's new formulation. The next morning I went down to my shop and discovered a fly had become stuck to the cloth surround on one of them. Feeling sorry for the littly guy, I took a popsicle stick and gently nudged it free of the goo.

Lookls like I may have uncovered another use for Roy's new fabric surround sealant - fly paper!

[genek]

Lookls like I may have uncovered another use for Roy's new fabric surround sealant - fly paper!

I wonder what the stuff they use to make real flypaper sticky is made of...

[kkantor]

I have a funny story to share. I recently coated a pair of older style AR3 woofers with Roy's new formulation. The next morning I went down to my shop and discovered a fly had become stuck to the cloth surround on one of them. Feeling sorry for the littly guy, I took a popsicle stick and gently nudged it free of the goo.

Lookls like I may have uncovered another use for Roy's new fabric surround sealant - fly paper!

Hellllppp Meeeee..... Somebody Helllppp Meeeeee.....

-k