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AR Cloth Surround Sealant?

The stethoscope would allow you to check all around the drivers to identify and remediate any air leaks that resulted from the kit construction. Either that, or stick your ear next to the woofer surround and follow the circumferance, while trying not to lose your hearing.
 
I just don't get how you could hear an air leak through a stethoscope when it's superimposed on massively amplified music blasting your eardrums into next Wednesday?
 
I just had "The Girl From Ipanema" blow the glue off the back of the surround (away from the steel basket) without it breaking form, so that gives you some idea how tough these surrounds are. Hit it with some tacky glue and I was right back in business.
 
There's historic photos of AR speaker builders in the factory listening through stethoscopes for air leaks. I've seen plenty of photos, and on mine, where extra putty sealer has been added around edges of mids and tweeters.
 
Correct Glenn.....and never knew why the mortite was added to my tweeters and mids in spots on my LST's until Tom Tyson explained they tested these speakers at the factory with the stethocopes and they added the mortite where they found leaks.
 
I'm new to AK and found this thread, because I'm restoring a pair of AR-4x's. In at least one spot, it looks like there's a crack in the surround (see photo; steel cable used to indicate location of apparent defect). Closer inspection didn't reveal an actual hole, so I'm thinking that the sealant has cracked, which probably has left a sort of vent in the surround. Given the apparent deterioration of the sealant since 1970 or so, would it be a good idea to apply thinner with a cloth or sponge and mop up the old sealant before applying the new?
 

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Geomorphdog said:
I'm new to AK and found this thread, because I'm restoring a pair of AR-4x's. In at least one spot, it looks like there's a crack in the surround (see photo; steel cable used to indicate location of apparent defect). Closer inspection didn't reveal an actual hole, so I'm thinking that the sealant has cracked, which probably has left a sort of vent in the surround. Given the apparent deterioration of the sealant since 1970 or so, would it be a good idea to apply thinner with a cloth or sponge and mop up the old sealant before applying the new?
Click to expand...
You can use toluline as that's the carrier for the butyl rubber in the sealer. Wipe the surrounds with it to clean, remove any remaining original sealer, then apply a very light application. These woofers are not designed to be 100% sealed as evidenced by the mesh dust caps which adt as vents.
 
Thanks. That's about what I figured. Just ordered some toluene. Rather tricky to come by. Found some "non-curing flow grade butyl" on I'm-a-gone. And "non-curable" duct sealing compound. I finished restoring the pots a couple of days ago. The center conductors were both so degraded by pitting that no amount of cleaning could make them work. My hillbilly engineering solution: copper foil tape cut into a donut and layered on top with lots of solder. That worked; I just hope it's durable. I figure I should replace the stuffing and shrouds. The old stuffing is shedding so much super-fine glass "dust," I don't want to handle it again. And the shrouds practically disintegrated to the touch. Any recommendations for shroud material?
 

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Geomorphdog said:
Thanks. That's about what I figured. Just ordered some toluene. Rather tricky to come by. Found some "non-curing flow grade butyl" on I'm-a-gone. And "non-curable" duct sealing compound. I finished restoring the pots a couple of days ago. The center conductors were both so degraded by pitting that no amount of cleaning could make them work. My hillbilly engineering solution: copper foil tape cut into a donut and layered on top with lots of solder. That worked; I just hope it's durable. I figure I should replace the stuffing and shrouds. The old stuffing is shedding so much super-fine glass "dust," I don't want to handle it again. And the shrouds practically disintegrated to the touch. Any recommendations for shroud material?
Click to expand...
Not sure really what you mean by shrouds.
 
GD70 said:
Not sure really what you mean by shrouds.
Click to expand...
I mean the super-light fabric between the woofer and the insulation. It's visible in the picture. I haven't examined it very carefully because it's so fragile and tears if you look at it funny, but it looks like a relatively fine weave, but very thin, very light. I think the idea is to be transparent to sound but a barrier to glass dust from the insulation.
 

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Geomorphdog said:
I mean the super-light fabric between the woofer and the insulation. It's visible in the picture. I haven't examined it very carefully because it's so fragile and tears if you look at it funny, but it looks like a relatively fine weave, but very thin, very light. I think the idea is to be transparent to sound but a barrier to glass dust from the insulation.
Click to expand...
I’ve reused it every time. Just handle with care.
 
GD70 said:
You can use toluline as that's the carrier for the butyl rubber in the sealer. Wipe the surrounds with it to clean, remove any remaining original sealer, then apply a very light application. These woofers are not designed to be 100% sealed as evidenced by the mesh dust caps which adt as vents.
Click to expand...

I remember seeing a tech note from either AR or KLH, I want to say the latter, stating that any speakers brought in for service should get a coat of dope on both the surround and dust cap.
 
N8Nagel said:
I remember seeing a tech note from either AR or KLH, I want to say the latter, stating that any speakers brought in for service should get a coat of dope on both the surround and dust cap.
Click to expand...

Only for KLH's. Here's the 4x woofer from the set I use to own. Note the dust cap, and an early KLH Six woofer where you can clearly see the sealer on the dust cap.

Cheers, Glenn
IMG_2490_zps87d071c4.JPG Early Six Woofer.jpg
 
GD70 said:
Only for KLH's. Here's the 4x woofer from the set I use to own. Note the dust cap, and an early KLH Six woofer where you can clearly see the sealer on the dust cap.

Cheers, Glenn
View attachment 1879833 View attachment 1879834
Click to expand...
Cool. Good to know. Thanks, Glenn! I wasn't confident that anyone would pay attention to a post on an old thread by a noob. Then again, AK seems to be populated by some of the friendliest folks on the internet.

If you're interested in my progress, I've been posting updates to Instagram, @Geomorphdog.
 
BTW I have a set of cabs with XOs and the paperwork still on the back for these. (no drivers) if anyone is interested. I'm in Vancouver WA. Will not ship. PM me if you need them.
 
GD70 said:
Only for KLH's. Here's the 4x woofer from the set I use to own. Note the dust cap, and an early KLH Six woofer where you can clearly see the sealer on the dust cap.

Cheers, Glenn
View attachment 1879833 View attachment 1879834
Click to expand...

I'd post some pictures, but Google Photos is slow to load tonight. I guess I can direct you again to my Instragram (@Geomorphdog). Anyway, the speakers came out nicely. I think the surrounds could probably use another coat of rubber, but I'm not eager to mix up another batch. Toluene is nasty stuff!
 
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