proofing AR driver cones

[kkc]

I am currently rebuilding my AR9s and was wondering if it might be a good idea to spray the cones with some sort of spray that prevents the paper from deteriorating (mould, sagging etc...)? Any ideas would be appreciated. I suppose any solution must not significantly alter the weight of the cone. What about altering the composition of the cone material?

Thanks, kkc

[tysontom]

I am currently rebuilding my AR9s and was wondering if it might be a good idea to spray the cones with some sort of spray that prevents the paper from deteriorating (mould, sagging etc...)? Any ideas would be appreciated. I suppose any solution must not significantly alter the weight of the cone. What about altering the composition of the cone material?

Thanks, kkc

Dear kkc:

There is no need to coat the woofer cones with anything whatsoever. If something appeared on the cone surface, which would occur only in very humid environments, you could simply wipe it off and forget about it. On the other hand, should you coat the cone with a lacquer, epoxy or enamel material, the cone could become quite rigid, and the woofer's frequency response might be adversely affected. The cones might also "ring" like a bell at certain frequencies. Therefore, it is desirable for the woofer cones to be pliable so as to absorb unwanted resonances and reflections up and down the cone, even at the very low frequencies of operation. It is always best to leave the felted-paper cone material as it was originally.

--Tom Tyson

[KlausDK]

I suppose any solution must not significantly alter the weight of the cone.

Hi kkc

Tom is of course right in his advice, however, I have had a few cases where the paper cone material was so fragile, that it could hardly hold together. In these cases I have succesfully used dammar, which is an extremely light weight product, not top add weight to the cone. Pls follow the link foor further details:

http://www10.big.or.jp/~dh/tips/dammar.html

BRgds Klaus

[kkc]

I am amazed at some of the ideas people come up with. Klaus, did you notice any difference in sound after applying dammar?

My cones are infact just fine. When reading the page at your link, however, it is tempting to apply some dammar even though I understand Tom Tyson's comments.

kkc

[RoyC]

Hi kkc

Tom is of course right in his advice, however, I have had a few cases where the paper cone material was so fragile, that it could hardly hold together. In these cases I have succesfully used dammar, which is an extremely light weight product, not top add weight to the cone. Pls follow the link foor further details:

http://www10.big.or.jp/~dh/tips/dammar.html

BRgds Klaus

Hmmm..."botanical sap" or "the fermented juice of persimmon fruit"...and for a bigger smile, at what cost? On the other hand, fermented fruit juice has been making music sound better for a very long time

Roy

[KlausDK]

On the other hand, fermented fruit juice has been making music sound better for a very long time

Hi Roy and kkc

The fermented fruitjuice goes without saying, I allways use that.

The dammar's sound improving effects, as referred to in the link, is probably in the higher frequencies for full-tone drivers as Lowther and Coral. I use it to restructure the decomposed paper mass of the cone with focus on adding as little weight as possible. I have also used it with a little blue/black pigment powder in cases where the cone was bleached by sun-light and had lost almost all its colour. The dammar will fix the colour pigment to the cone surface with very little weight added. The photo shows a 12" driver after this treatment.

BRgds Klaus

[frankmarsi]

8-1-08

Regarding that 'joy-juice'..........

Some of my 12 inch woofers have faded over the years to a medium gray tone and some even have red 'china-marker', grease pencil-

writing on them, usually the letter 'P', which I guess AR personal used that letter to signify it may have passed certain tests cause I sometimes see the 'P' on tweets and mids too.

I thought perhaps the old liquid black shoe polish I used to shine my shoes up (when I didn't want to use the paste and horse-hair brushes that my father insist I use, and not that cheap liquid crap) with in the past might make a better coating with-out adding weight to the cone structure. But in my thinking I also realized that the cone will become wet and may deform and maybe even become mis-aligned and weaken the composition of the cone material.

I presume it's just best to do nothing and not think about shining the old girl up too much as its main job is to

reproduce sound, not necessarily look good.

FM

P.S. on another topic, those 2 AR-3a cabinets I luckily bought on eBay 2 weeks ago ($89.00 for two of them, please don't hate me cause I'm beautiful) have been delivered and are almost flawless. Out of 16 corners, 15 are so sharp and pointed (perfect) with no damage one could even get hurt on them, only one back corner is slightly dented. My question is would I, the cabinets that is, benefit from me going inside and adding some old "Franklin's" wood glue (my father had some down the basement, at least 40 yrs. old) to the bracing joints along the long interior walls. The cabinets are empty as I have not had the time to start their wonderful 're-birth'. Every time I pass them I give a little 'knuckle-wrap' against the empty boxes and hear a slight, well it almost sounds like wood being loose against another piece of wood.

Any ideas if using a strong glue would help in any way even if the joints are tight, or even doing some further simple additional bracing?

Thanks, FM

[Mexicomike]

Don't use 40 year old glue - it's no good unless it is hide glue flakes which must be mixed with water and heated to the proper temp before using (around 140F)! Also, adding glue to existing joints will not do anything. If the joints are separated, then they need to be removed and the glued surface cleaned thorougly. With the exception of hot hide glue being applied to a joint that was originally made with hide glue, no other glue will adhere to old glue, even of the same type.