cleaned polydome

[Listnnthdark]

Thanks much dexter !
EXCELENT POINT " It might go wrong and then what " ?
The then what for me means NO MUSIC and that is not an option . Mine are really perfectly fine . Just a little yellowed with age . { who isnt ? }
While it would be nice to have them look clearer its about the moisturization factor giving them increased life span .. I think doing the outsides only will acomplish the goal of increasing pliabilty and life span so thats what Im going to do . Viva la Kappas !

 

[DexterB]

Thanks much dexter !
EXCELENT POINT " It might go wrong and then what " ?
The then what for me means NO MUSIC and that is not an option . Mine are really perfectly fine . Just a little yellowed with age . { who isnt ? }
While it would be nice to have them look clearer its about the moisturization factor giving them increased life span .. I think doing the outsides only will acomplish the goal of increasing pliabilty and life span so thats what Im going to do . Viva la Kappas !

Glad I could be of service!
Enjoy your Kappas!

 

[Altair]

Hi, I also have a pair of K8s that I recently acquired, and I did this treatment to one dome that was totally yellow and opaque. I used a product by Simoniz and was successful. Now I find this thread, one week late.

I believe that the important ingredient in the product to use is: PLASTICISERS
This is what allows plastics to be soft and pliable.
And this is the ingredient that has been probably long gone from the dome material.
I would love if a plastics engineer could come here and comment on this, and tell us exactly what is the best product to use. Or where to find plasticisers in small qty.
A quick search on google gave me nothing.

Anyway, I'm covinced that this treatment will extend the life of the cones by many years.

Cheers

 

[tubed]

Perhaps, in order to extend the life of these drivers, the more applications of "moisturizer" the better...perhaps once a month?

 

[DexterB]

I believe that the important ingredient in the product to use is: PLASTICISERS
This is what allows plastics to be soft and pliable.
And this is the ingredient that has been probably long gone from the dome material.
I would love if a plastics engineer could come here and comment on this, and tell us exactly what is the best product to use. Or where to find plasticisers in small qty.
A quick search on google gave me nothing.

Anyway, I'm covinced that this treatment will extend the life of the cones by many years.

Interesting theory but not entirely correct IMHO.
Let me get into this by starting of with some quotes from the Autoglym website regarding the Vinyl and Rubber Care product.

Autoglym Vinyl & Rubber Care is a plastic dressing that can be applied to interior and exterior plastics. It will offer limited protection to areas that are prone to cracking. Plastic will dry out over many years and if there is a stress on an area it may crack, although this often takes a long time, if it even happens at all.
Autoglym Vinyl & Rubber Care conditions and protects interior and exterior surfaces and forms a tough, but flexible, anti-static barrier against moisture, dust, oxidation, staining and fading.
Autoglym Vinyl & Rubber Care can be used to provide either a high or low shine finish on plastic trim. There are instructions on the rear of the bottle describing how to achieve the desired finish.

Regarding the actual content of Autoglym Vinyl and Rubber Care (which was what I used) there is not much information to be found.
I did however found out that it is an conditioning emulsifier which is non-viscous, has a PH value between 7 and 9 and it has a relative density of 0.925

If you want to find out more you can find a Safety Data Sheet on this product HERE

Unfortunately this Data Sheet doesn't say anything about what ingredients are specifically used in this emulsifier, but I did found out that it contains silicone (which is a polymer) and emulgators.
Now silicone is amongst many other things known for its excellent resistance to oxygen, ozone and UV light (sunlight).
So, I would say that the main ingredient that makes this product work is Silicone and not a plasticizer, since that is an important part of the actual material used to fabricate the domes and keep them soft and pliable.

To summarize what I'm trying to explain here:

Plasticizers are used in the fabrication process of the Polydomes.
They do not slowly disappear over the years, but will lose a significant part of their prime quality which is making the Polydomes soft and pliable.
This is caused by the continuous exposure to UV light, which is not the same thing as being exposed to direct sunlight.
The latter is the worst form of exposure, but one must realize that we are all exposed to UV light all day long, even if we are not in direct sunlight!
Also (high) temperature will play an important part in the process of deterioration and aging of our Polydomes.
And to stop this process (or at least slow it down significantly) we are now using Vinyl and Rubber Care dressing (from Meguiars, Autoglym or Simoniz and probably a few more) which contains Silicon that gives our Polydomes a protective layer whilst at the same time conditioning them.

So, there you have my view upon this matter..... and just as Altair did, I too welcome any input from knowledgeable professionals who can give us a better insight in this matter. :yes:
To end I have some food for thought: Why come speakers equipped with protective covers only to be removed as soon as we put them in our house?
Do these covers protect (to a certain extent) from UV light? :scratch2:

 

[DexterB]

Perhaps, in order to extend the life of these drivers, the more applications of "moisturizer" the better...perhaps once a month?

Since this is a deterioration process that takes a very long time, I guess it will not need proper care very often to stop it.
So therefore i have decided to do the outside of my domes once a year.
The inside will get another turn as soon as I can see the least bit of evidence of residue build up. :yes:

However I can understand that people who own Polydomes which are in really bad shape would want to give the treatment more often.
But do not forget that every time you put this stuff on your domes, you are putting a new protective layer on the previous one.
I wonder if this will influence its effectiveness since the dome material is already protected.

Compare it with waxing your car: Waxing it with a sealant is great especially when the car has not seen proper care for a long time, but will not bring better results if you do it every week after applying the first layer of waxing sealant.

 

[Altair]

Thanks Dexter for this extensive explanation.
I would be concerned that a regular application of some protective layer coating might build-up with time and change the mass of the dome enough to alter the frequency response. However, with a silicone-based product, I suppose it cannot build-up because silicone doesn't dry. If you put too much, it will just run off the surface.
At least, silicone restored the transparence of the dome.

I am still not convinced that silicone is the right compound to soften plastics that have hardened with time, because I don't think silicone is even used in the making of plastics But you're right, plasticizers are used in the manufacture of plastics but probably wouldn't be of much use now anyway.

Regarding UV light and sun exposure, those are indeed the main culprits of the degradation in all plastics. On my K8s that I just bought, only one Polydome was yellowed and opaque. Must have been the one that was exposed to sunlight from time to time.

There is another thing that concerns me and it is the fact that, if ever replacement domes become available, (just the dome & suspension, without the voicecoil) I wonder how it will be possible to glue that back to a voicecoil that previously had silicone on it...

 

[DexterB]

There is another thing that concerns me and it is the fact that, if ever replacement domes become available, (just the dome & suspension, without the voicecoil) I wonder how it will be possible to glue that back to a voicecoil that previously had silicone on it...

When I was much younger (35 years ago) and I worked in a body-shop we used a substance called Prepsol to clean automobiles thoroughly before they got a new lacquer coating.
Prepsol is still readily available today, so I guess that silicone residue would present no problem at all. :thmbsp:

 

[Listnnthdark]

I did the outside with meguiars " plastx "
The domes are just a bit clearer though not much . I also cleaned the woofer cones with it . they were filthy . Hopefully it will help but im not going to open them up and clean the inside , I can see that what was not taken off the outside is the stuff on the inside But Im done for now .
the sound looks quite nice .. clean and shiny ..

 

[ScooterDude]

...cleaned the PolyDome Ks on my Kappa 7s with Mothers VLR (Vinyl Leather Rubber) Cleaner & Conditioner. It's a new product and besides, I couldn't find the Maguires product that everyone was recommending in my local auto parts stores. So I used a similar product from Mothers; it contains Lanolin and Neets Foot oil. It seemed to to do a very good job at cleaning up the newest PolyDome which was starting to cloud up. The other (older) PolyDome was much worse. I spent about and hour on it. It did clear up while it was still damp, but when the Mothers started to dry, it started to cloud up again. It still looks and feels way better that it did before I started. They both sound great. This is probably a good thing for anyone with PolyDome drivers to do. It is not very difficult and the drivers aren't as fragile as one would think.

I will try it on my Kappa 6s when I get them back to the house.

 

[14G-])utch^]

Interesting theory but not entirely correct IMHO.
Let me get into this by starting of with some quotes from the Autoglym website regarding the Vinyl and Rubber Care product.

Autoglym Vinyl & Rubber Care is a plastic dressing that can be applied to interior and exterior plastics. It will offer limited protection to areas that are prone to cracking. Plastic will dry out over many years and if there is a stress on an area it may crack, although this often takes a long time, if it even happens at all.
Autoglym Vinyl & Rubber Care conditions and protects interior and exterior surfaces and forms a tough, but flexible, anti-static barrier against moisture, dust, oxidation, staining and fading.
Autoglym Vinyl & Rubber Care can be used to provide either a high or low shine finish on plastic trim. There are instructions on the rear of the bottle describing how to achieve the desired finish.

Regarding the actual content of Autoglym Vinyl and Rubber Care (which was what I used) there is not much information to be found.
I did however found out that it is an conditioning emulsifier which is non-viscous, has a PH value between 7 and 9 and it has a relative density of 0.925

If you want to find out more you can find a Safety Data Sheet on this product HERE

Unfortunately this Data Sheet doesn't say anything about what ingredients are specifically used in this emulsifier, but I did found out that it contains silicone (which is a polymer) and emulgators.
Now silicone is amongst many other things known for its excellent resistance to oxygen, ozone and UV light (sunlight).
So, I would say that the main ingredient that makes this product work is Silicone and not a plasticizer, since that is an important part of the actual material used to fabricate the domes and keep them soft and pliable.

To summarize what I'm trying to explain here:

Plasticizers are used in the fabrication process of the Polydomes.
They do not slowly disappear over the years, but will lose a significant part of their prime quality which is making the Polydomes soft and pliable.
This is caused by the continuous exposure to UV light, which is not the same thing as being exposed to direct sunlight.
The latter is the worst form of exposure, but one must realize that we are all exposed to UV light all day long, even if we are not in direct sunlight!
Also (high) temperature will play an important part in the process of deterioration and aging of our Polydomes.
And to stop this process (or at least slow it down significantly) we are now using Vinyl and Rubber Care dressing (from Meguiars, Autoglym or Simoniz and probably a few more) which contains Silicon that gives our Polydomes a protective layer whilst at the same time conditioning them.

So, there you have my view upon this matter..... and just as Altair did, I too welcome any input from knowledgeable professionals who can give us a better insight in this matter. :yes:
To end I have some food for thought: Why come speakers equipped with protective covers only to be removed as soon as we put them in our house?
Do these covers protect (to a certain extent) from UV light? :scratch2:

My friends Kappa 6's were in his basement with grill covers always on. The domes still went opaque. While for many UV exposure is I am sure a component, I would guess ordinary environmental oxidation (Ozone) is the main culprit.

 

[IsakAlexande]

Did repair a kappa 9.2i polydome here the other day, it had a break on the negative pole. Anyhow, the coating inside the dome looks very similar to wax and this will explain why they get clear when heated with a hair dryer..? I would guess the wax coating helps stiffen up the dome so what happens when you clean it off, less top end response?

 

[Love-Vinyl]

I do a yearly spring cleaning on my RS3b's midrange and woofers with filtered cold water that I dampen a clean VERY soft cloth with. When I first got them they had been used as a party system with a LOT of grunge on them. They hadn't been treated well at all. I had considered other things but thought I'd give this a try first. They had a brown grunge coating on them that was difficult to budge at first but after a few days of cleaning, letting them dry, then cleaning again I did manage to get it off. I can see everything inside as well as possible. After this cleaning I do a quick wipe off with another VERY soft cloth and after 8 years of daily use they are still clean, clear and working fine.

I was tempted by several tweaks concerning Armor All, McGuiars. et. all and after reading a few chemical engineers responses chose to never let them anywhere near. It seems these items do their job by forming a chemical bond with the material that makes it more elastic but at a price. You have to keep doing it or it will break down the material you put it on. And that to me was the death knell of anything to do with it. If your speaker requires a certain stiffness to sound it's best, what will softening do to the sound? A laid back or more reserved sound sure to come? I would think so but I am not an engineer, chemist or anything resembling one so I can't speak to it personally. More than a few had put this on their rubber surrounds as well thinking to keep them in tip top shape only to discover they began to crack at an alarming rate.

From my limited understanding the Polycell material is very tough and durable and isn't nearly as prone to cracking or breaking as other materials which is one reason it was chosen. Infinity has always been fascinated it seems with exotic materials and drivers in strange combinations that just work and VERY WELL to my ears. I prefer to not take chances and do my simple spring cleaning each year. Oh and I use a little computer vacuum on the EMITS as it's VERY low suction, it barely pulls anything, but it does get those little bits of dust out of the diaphragms. I also keep the grills on and clean them on a regular basis as well. They're all still original but with obvious signs of the abuse they got before. :nono:

I use Old English on the walnut veneer several times a year and while some of the wrap around veneer is starting to pull loose, they still look good!

If I can ever get around to getting a digital camera I'll take some pictures...

 

[molecules01]

treating polydomes

I agree. I would never put anything on the domes, unless it was a desperate attempt on a brittle dome. They change the physical properties and would likely alter the critical midrange. I would be even less likely to use a hair dryer. Adding heat will shorten the lifespan (as it will with anything, it is like running an accelerated aging test).

 

[yohalfprice]

I just noticed this thread resurrected, as I have a pair of the polydome mids.

I am a chemical engineer BTW, but I have not worked in polymers in many years and I'm no expert at all on the subject. Probably 90% of Chem E's and chemists would also have to admit the same.

I did find information suggesting the poly domes are manufactured from polypropylene.

Per Wiki:

Polypropylene

Degradation

Polypropylene is liable to chain degradation from exposure to heat and UV radiation such as that present in sunlight. Oxidation usually occurs at the tertiary carbon atom present in every repeat unit. A free radical is formed here, and then reacts further with oxygen, followed by chain scission to yield aldehydes and carboxylic acids. In external applications, it shows up as a network of fine cracks and crazes that become deeper and more severe with time of exposure.

For external applications, UV-absorbing additives must be used. Carbon black also provides some protection from UV attack. The polymer can also be oxidized at high temperatures, a common problem during molding operations. Anti-oxidants are normally added to prevent polymer degradation.

Of course, the anti-oxidants discussed are part of the manufacturing process, but it might be possible to find a suitable anti-oxidant coating as an after market application. I have no real opinion on the Meguire's product, but I did notice that it contains an emolient (I think aloe vera) which would explain the sticky or waxy residue noted above.

Mine are in seemingly very good condition but I will try to look into this more at some point.

 

[standuffer]

So, I’ve read this whole thread and I agree that our Polydomes probably DO need some sort of conditioner / protectant.

My question is…
What is the purpose of these polypropylene domes to the performance of the drivers themselves?

 

[tuffstuff1]

So, I’ve read this whole thread and I agree that our Polydomes probably DO need some sort of conditioner / protectant.

My question is…
What is the purpose of these polypropylene domes to the performance of the drivers themselves?

I would like to know too.

 

[Zyrzox]

So, I’ve read this whole thread and I agree that our Polydomes probably DO need some sort of conditioner / protectant.

My question is…
What is the purpose of these polypropylene domes to the performance of the drivers themselves?

I'm pretty sure (but really just guessing) they're there as a barrier diffuser to buffer/soften/dampen what might otherwise be very harsh and potentially irritating frequencies...to make their output easier on the ears, so to speak. I'm also guessing that the material used was chosen because of its "fleshy" characteristics to give the sound a more natural/organic quality.

I'm going to do some more research before I decide how I'm going to clean/protect my domes - which are yellow but still springy. I'll certainly share my findings should I come across any options that haven't previously been mentioned here.

 

[loquatious]

you poly-driver guys amaze me. the devotion to eking a bit more life out of something you know is eventually going to fail is inspiring (like marrying someone that you know has a terminal illness). my hat is off to you.

i know the meguires treatment has yielded good results for putting off the inevitable in terms of the cloudiness, but i don't see that it really addresses the cause of the malady, UV and an ozone depleted atmosphere. the various polishes don't seem to really offer much as a protectant.

i'm wondering if anyone has looked into 303protectant which is specifically aimed at those issues that cause the deterioration in the first place. it's safe to use on polys, and has no silicones or petroleum distillates. seems like a good step to take to augment the meguires routine.


http://www.goldeagle.com/product/303-aerospace-protectant









.

 

[Newk_Yuler]

you poly-driver guys amaze me. the devotion to eking a bit more life out of something you know is eventually going to fail is inspiring (like marrying someone that you know has a terminal illness). my hat is off to you.

It's not a foregone conclusion that all Kappa Polydomes will rot. It depends on how they've been kept over the years. If they're in extraordinary shape when acquired it's possible to keep them in an environment that will allow them to remain in very good shape with no other special treatment for a very long time. Unfortunately the majority of Kappa Polydomes you'll find in speakers for sale and as used replacements are set into decay because of some common form of exposure that causes susceptible polypropylene to begin to degrade. Still not necessarily a death sentence. Those with light to moderate decay can be maintained and with proper care should last a very long time. Maybe indefinitely. Certainly no reason to shy away from a set of Kappas until you know the Polydomes are in particularly bad shape.

The 303 protectant you mentioned looks very interesting. Not sure it hasn't been suggested before. If it's dry after application it may have an advantage over Meguire's protectants that remain partially wet. Protectants that remain wet for a period of time after application dampen the Polydome's performance to some degree. The 303 is at least as common as Meguire's products in stores where you find that sort of product. It's also apparently a lot more expensive.