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Proper sealant adhesive for metal speaker cabinets?

djnagle said:
The pro LX5 are keepers.
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Agreed. When I first bought hem new (nearly 30 years ago) I went into the store intending to buy a pair of white minimus 77's, as those were on sale, and white finish fit the room I planned to use them in at the time. But then the salesman talked me into buying the last pair of Pro LX5 he had in stock (there had just been a minor design change, and new catalog number assigned for future shipments) and he made me a pretty solid deal on the last pair of "old design" (which really wasn't substantively different anyway, as it turned out). After listening to them, I decided I liked them better (despite not being available in white, as I'd planned to buy) than the 77's, so that was that.

I noticed about 2 months ago that there was a tear forming in one of the woofer surrounds, just age-related failure. So they were promptly taken out of service to prevent any real damage, and now are awaiting some bench time. I already have the parts in hand.
 
Are you looking to permanently seal the back in place or would you want easy, not so easy or difficult but possible access. There is at least one product out there for each of those 4 scenarios. Your choice would help with our recommendations.

Add to that the difficulty of complete removal is needed and of course the finished look of the sealed cabinet.
 
I want something strong, but potentially removable (as with the factory sealant used). The finished look of the cabinet is not so much a concern, the way the rear panel "tucks" into a flange means the adhesive head is not visible externally (unless one is sloppy in application). As of now, I'm favoring either Lexel, or maybe a RTV silicone sealant, unless a case can be made for some specific product more suited to the application.l
 
Sansuiman said:
I want something strong, but potentially removable (as with the factory sealant used). The finished look of the cabinet is not so much a concern, the way the rear panel "tucks" into a flange means the adhesive head is not visible externally (unless one is sloppy in application). As of now, I'm favoring either Lexel, or maybe a RTV silicone sealant, unless a case can be made for some specific product more suited to the application.l
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Why not that black permatex RTV they sell in auto parts stores? I use it to fix all sorts of things, I think it'd do a pretty good job here.

How's the J11? What are the surrounds made of?
 
The J11 are ok, obviously the low end response is limited by their design, as one would expect. Pretty sold little speakers, and I purchased both pair from Japan, as they are exceedingly rare in the US. Not terribly common in the JDM either, actually.

Surrounds on the woofer and the passive radiator are butyl rubber, but oddly the woofer surrounds deteriorate badly while those on the drone cone don't. I managed to redo the woofers, though the surrounds I was able to get weren't quite an exact replacement. Unless one really has a fixation for this particular model Sansui speaker, and can find them inexpensively, I'd probably not bother. There are other more readily available mini speakers of this general variety that are quite likely better performers.

As to using RTV (or not), it is under consideration. When I originally posted this thread, I was thinking I might learn there was some specific, purpose made product used in sealing metal speaker enclosures, since whatever it is the factory used is unfamiliar to me in appearance and "feel". But so far, most suggestions have been for things I'd already considered; which is fine, I just thought there might be some outlier answer for something I was unaware of that would pop up inn discussion here.
 
Sansuiman said:
The J11 are ok, obviously the low end response is limited by their design, as one would expect. Pretty sold little speakers, and I purchased both pair from Japan, as they are exceedingly rare in the US. Not terribly common in the JDM either, actually.

Surrounds on the woofer and the passive radiator are butyl rubber, but oddly the woofer surrounds deteriorate badly while those on the drone cone don't. I managed to redo the woofers, though the surrounds I was able to get weren't quite an exact replacement. Unless one really has a fixation for this particular model Sansui speaker, and can find them inexpensively, I'd probably not bother. There are other more readily available mini speakers of this general variety that are quite likely better performers.

As to using RTV (or not), it is under consideration. When I originally posted this thread, I was thinking I might learn there was some specific, purpose made product used in sealing metal speaker enclosures, since whatever it is the factory used is unfamiliar to me in appearance and "feel". But so far, most suggestions have been for things I'd already considered; which is fine, I just thought there might be some outlier answer for something I was unaware of that would pop up inn discussion here.
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Thanks for the review. It's too bad they're little disappointing, but if nothing else they're sure ahead of their time. So many mini speakers now use passive radiators!

Speaker manufacturing uses all kinds of specialty adhesives, however there's very little that can't be substituted with either RTV, two part epoxy, contact cement, or PVA glue. I wouldn't be surprised if it's some special cyanoacrylate which was used originally, but you can use something slower curing and more flexible as a repair.
 
Some answers here have understandably recommended various RTV silicones -- these responses are on the right track, BUT, as some responses here have pointed out, it must be a neutral cure silicone - the standard, most common variety is acetoxy cure - it gives off a vinegar smell ( the same basic smell as those clear Craftsman screwdriver handles) and is corrosive and potentially harmful to components ( think sealed cabinet)

Dow 737 is an example of the good stuff. Above, someone has mentioned Sikaflex, another good choice (if you click on the link you'll see non-corrosive in its product description)
 
Johnny7 said:
Some answers here have understandably recommended various RTV silicones -- these responses are on the right track, BUT, as some responses here have pointed out, it must be a neutral cure silicone - the standard, most common variety is acetoxy cure - it gives off a vinegar smell ( the same basic smell as those clear Craftsman screwdriver handles) and is corrosive and potentially harmful to components ( think sealed cabinet)

Dow 737 is an example of the good stuff. Above, someone has mentioned Sikaflex, another good choice (if you click on the link you'll see non-corrosive in its product description)
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Any product equivalent to Sikaflex can be used, for example products from 3M or other top manufacturers. I am very satisfied with Sika products and that is why I suggested that option.
 
Sansuiman said:
The J11 are ok, obviously the low end response is limited by their design, as one would expect. Pretty sold little speakers, and I purchased both pair from Japan, as they are exceedingly rare in the US. Not terribly common in the JDM either, actually.

Surrounds on the woofer and the passive radiator are butyl rubber, but oddly the woofer surrounds deteriorate badly while those on the drone cone don't. I managed to redo the woofers, though the surrounds I was able to get weren't quite an exact replacement. Unless one really has a fixation for this particular model Sansui speaker, and can find them inexpensively, I'd probably not bother. There are other more readily available mini speakers of this general variety that are quite likely better performers.

As to using RTV (or not), it is under consideration. When I originally posted this thread, I was thinking I might learn there was some specific, purpose made product used in sealing metal speaker enclosures, since whatever it is the factory used is unfamiliar to me in appearance and "feel". But so far, most suggestions have been for things I'd already considered; which is fine, I just thought there might be some outlier answer for something I was unaware of that would pop up inn discussion here.
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I would go with a 3-M VHB Tape. https://www.3m.com/3M/en_US/vhb-tap...c9g9aWkJR7a_8GtZVSZy7tVfEKAKCSrxoCoQgQAvD_BwE
 
@CrazyTrain, I hadn't considered VHB, but I do have some 5/16" wide left over from applying some trim to one of my cars recently, maybe I'll give that a look. It's an interesting suggestion.
 
Massive fan of vhb. Killer stuff. Not the white foam crap, the clear version.

The white foam tape should be banned. It's crap.

Very very hard to use on an inset panel. And in this case it's permanent as you'd bend the rear panel before you ever got it out again.
 
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