AR5 woofer seals

[wilson]

Hi, I just picked up a pair of AR-5's in need of a re-foam, but otherwise in pretty good shape. It didn't seem that the grills had ever been off, however when I pulled out the woofers they were sealed to the cabinet with just a white foam gasket. Is this original? I was under the impression that there was some kind of sealant compound used, however there is no residue on the cabinet.

I just want to make sure that they go back together properly sealed. btw, these are 4 screw drivers marked 1972.

Thanks.

[genek]

Hi, I just picked up a pair of AR-5's in need of a re-foam, but otherwise in pretty good shape. It didn't seem that the grills had ever been off, however when I pulled out the woofers they were sealed to the cabinet with just a white foam gasket. Is this original? I was under the impression that there was some kind of sealant compound used, however there is no residue on the cabinet.

Black mor-tite sealing compound was used in classic ARs until the early 70's, when AR switched to the white foam gaskets. If your woofers have never been removed you may be able to get away with reusing the gasket once or twice, but you'll need to check for leaks. Safest thing to do is replace it. You can either use ordinary gray rope caulk or cut strips of self-adhesive foam weatherstripping and stick it to the cabinet or woofer.

[RoyC]

Hi, I just picked up a pair of AR-5's in need of a re-foam, but otherwise in pretty good shape. It didn't seem that the grills had ever been off, however when I pulled out the woofers they were sealed to the cabinet with just a white foam gasket. Is this original? I was under the impression that there was some kind of sealant compound used, however there is no residue on the cabinet.

I just want to make sure that they go back together properly sealed. btw, these are 4 screw drivers marked 1972.

Thanks.

AR eventually switched to all foam gaskets. The white foam is original.

Roy

[wilson]

Black mor-tite sealing compound was used in classic ARs until the early 70's, when AR switched to the white foam gaskets. If your woofers have never been removed you may be able to get away with reusing the gasket once or twice, but you'll need to check for leaks. Safest thing to do is replace it. You can either use ordinary gray rope caulk or cut strips of self-adhesive foam weatherstripping and stick it to the cabinet or woofer.

Thanks - I like the gray rope caulk idea - sounds simple and effective. So it does seem that nobody has been inside these speakers- rheostats are nice and silver- no sign of corrosion. looks like I got lucky.

Thanks for your help.

[genek]

Thanks - I like the gray rope caulk idea - sounds simple and effective. So it does seem that nobody has been inside these speakers- rheostats are nice and silver- no sign of corrosion. looks like I got lucky.

Have you opened up any of the controls? The corrosion that really matter is on the inside.

[RoyC]

Thanks - I like the gray rope caulk idea - sounds simple and effective.

Thanks for your help.

I prefer to use "duct seal" (see pic) easily obtained from the electrical section of Home Depot. It is more pliable than the Mortite type rope caulk, and is the stuff re-packaged as "original" AR putty by Ebay's "Vintage AR". AR's putty was not Mortite (Advent's was). AR's black putty was softer and less clay-like than Mortite.

Parts Express also sells a black sealant much the same as AR's original, as well as a denser, more appropriate foam gasket tape than typical hardware store weatherstripping.

http://www.parts-express.com/wizards/searc...FTOKEN=48509746

Roy

[genek]

I prefer to use "duct seal" (see pic) easily obtained from the electrical section of Home Depot. It is more pliable than the Mortite type rope caulk, and is the stuff re-packaged as "original" AR putty by Ebay's "Vintage AR".

I pulled up the MSDS data on Ideal Duct Seal and compared it to typical grey construction caulk. Both are 60-70% butene polymer (adhesive) and calcium carbonate (filler), with the other 30% various other ingredients added for moisture and temperature resistance and to enhance their bonds to metal or wood (metal-to-metal for duct seal and wood-to-wood or metal for construction caulk). Basically, pretty much the same stuff. White rope caulk, which is commonly found in small rolls and feels a bit less sticky to the touch, is either titantium oxide or acrylic based. Considered less toxic, with easier cleanup and paintable. These materials are all formulated to the requirements of the same standard, UL 181B, and are considered functionally equivalent for electrical or construction use. As far as our needs for speaker sealer are concerned, use whichever one you're most comfortable working with, or comes in the most convenient form and packaging.

"Mor-tite," btw, while a brand-name, is widely used in the construction industry as slang for all these compounds, like "kleenex" for tissues, so don't feel the need to run out and look for that exact brand because somebody says "mor-tite."

That black stuff AR used to use was an oil/asphalt based roofing sealer and was also sold under the "Mor-tite" brand name (among others) for a time. Still available, but nasty stuff to work with and really not necessary for speakers.

The tape carried by P-E is self-adhesive closed-cell foam. As long as you make sure the stuff the hardware store is carrying is closed-cell, it's the same stuff. To P-E's credit, their price for a roll is about the same as Ace Hardare's, so they're not marking it up the way you often see common products priced to gouge when sold to audiophiles.

[wilson]

Have you opened up any of the controls? The corrosion that really matter is on the inside.

Yes - I mean that the actual resistor springs and contact are surprisingly clean.

[RoyC]

That black stuff AR used to use was an oil/asphalt based roofing sealer and was also sold under the "Mor-tite" brand name (among others) for a time. Still available, but nasty stuff to work with and really not necessary for speakers.

Agreed...

...and the black sealant sold by PE is more like the stickier duct seal.

I also agree that all of the above does the job quite well.

Roy

[johnieo]

I was under the impression that there was some kind of sealant compound used, however there is no residue on the cabinet.

Thanks.

Hello Wilson:

Woofer sealants are described in detail in the AR-3a restoration document found in the AR library. A half-dozen of folk representing countless years of practical hands-on restoration experience assembled it, because myriad identical questions had been posted. Were we to refer new requests for same information to that document, it might save lots of Mark's server space

Cheers, and may your restoration go well!

John