prevent hardening of speaker surrounds

Carl, as a former chemist, I have to inform you that all liquids are considered solvents. That is the position from which I am coming from. Water, is called the universal solvent(incorrectly, of course). I am not saying that Armor All would be good or bad for rubber. Just that care should be taken. Whenever I considered the usage of a polymer, I would receive product data from the manufacturer of that compound. Almost always, a solubility table is included. Showing which type of solvent(in general terms - alcohols, ethers, ketones, esters, aromatic or aliphatic hydrocarbons, etc.) a polymer is resistant to(and to what degree), and which it is not. More importantly, I would be interested in seeing the Material Safety Data Sheet(MSDS) on Armor All, which should list the components(including solvent[s]) contained. Every chemical in the USA has an MSDS, and the manufacturer is obligated to provide it to you(often available on the web these days). Otherwise, they get their pants sued off.

Well, if you are so interested in seeing this solubility table for Armor All, why aren't you asking them for it? Also, I did ask the speaker manufacturer specifically what their thoughts were before I applied Armor All, and they informed me that there would be no degradation of the rubber, and no interactions with the glue that holds the butyl rubber to the polypropylene cone. So you see, I took the only care that should have been taken, in my case. I didn't have to be a chemist to do it, either. BTW, the manufacturer is Dynaudio, and I feel that they might know a little bit more about speaker drivers (especially their own) than anyone who will ever contribute to this forum....and they have spoken.

According to the MSDS, the primary solvent contained in Armor All is Propasol P(a glycol ether). I won't bother listing other components. This solvent should be OK for butyl surrounds or epoxy(used in many adhesives - check with your manufacturer). However, it would not be safe for use on vinyl, acrylic, many polyesters(which also are used as adhesives), ethylcellulose, nitrocellulose, certain chloro or fluouropolymers(Saran or Kynar), or polyurethane. Do not use it on foam surrounds unless the foam is a polypropylene type. And make sure of the type of adhesive used to attach your surrounds. Also, keep it off your speaker's finish at all costs. These finishes are usually polyurethane or lacquer(usually nitrocellulose) based, and will be attacked by glycol ethers. Don't ruin that furniture quality finish you paid so much for in the first place.

Trelja; I want to thank you for your responses. Although I am not a chemist, I did get a minor in chemistry in college. I did not like the requirement of German for chem. majors and this was the rebellious 1960's, so of course I quit chem. Although there is no occidation occuring as yet, it is inevitable. The ozone in the atmosphere will see to that - as well as UV (a good reason to keep grills on). When you buy speakers as expensive as Aerial 10ts you want to keep them around for some time and in peak operating condition. It just seemed prudent to see if there was some way of maintaining the operating parameters of the speaker surrounds as long as possible. We audiophiles seem to obsess over things like jitter, green magic markers, pucks etc. that we forget that the suspension of a speaker is probably at least as important. Thaks again. mjdraper@earthlink.net

To clarify something, here, I agree that the suspension of the speaker is of paramount importance. However, it's the rear suspension on cone speakers (the spider, a woven fabric) where the primary burden lies, with respect to how the cone behaves, since it is connected to the "balanced center" of the moving mass of the diaphragm. The front "surround" serves primarily to keep the cone centered during motion, and serves an extremely minute roll in the "suspending" of the diaphragm's mass. Therefore, changes in sonic performance over time are due to changes/wear in the spider, and not so much from the front surround. SUBARU ALLUDES TO THIS ABOVE.