Best material for a polydome

Discussion in 'Infinity Loudspeakers' started by sagebug, Dec 3, 2015.

  1. swechsler

    swechsler Frog Whisperer

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    Waking this thread up...

    I did a little investigation, the dust cap that Millersound is using as a replacement dome appears to be the same as (or similar to) the dust cap used in the Kappa and (believe it or not) SM series woofers. Due to the lack of support from Infinity for vintage products, I have to wonder who made these. Simply Speakers sells them and describes them as being "foam over screen". They are also available on eBay. Don't know if they're exactly the same as the ones used by Millersound, but I can't imagine many different folks manufacturing something like this.
     
  2. TopDollar69

    TopDollar69 New Member

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    What did everyone end up using for glue? I have one Polydome that has a crack near the voice coil that I would like to repair. Also, does anyone know of a foam covered cloth dust cap that is smooth (ie no Infinty logo) that would be correct for the Kappa woofers?
     
  3. TopDollar69

    TopDollar69 New Member

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    No need for the glue now. After I let the dome sit with silicone shock oil on it for a couple of days and then tried rubbing some of the more cloudy areas with my finger the polydome material stated to crack all along the voice coil. Soon after that the dome part started to fall apart where I was touching it. I would not touch the dome after putting silicone oil on it. It could be the brand of oil I used, but I wouldn't recommend anyone else try it. Since the dome was bad anyways I warmed up the pieces with a hair dryer and it cleared right up and got softer. It stayed soft and pliable after it cooled as well. I'm not sure if that had anything to do with the silicone oil that was already on it or not. I would like to point out that this dome was good when I started, it was milky but not hard or cracked.
     
  4. swechsler

    swechsler Frog Whisperer

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    Heating the polydome material is only a temporary fix; they will soon get hard again.
     
  5. okeeteekid

    okeeteekid Well-Known Member

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    I used silicone shock oil on mine for years and they still look new.
     
  6. vinerp

    vinerp New Member

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    Good evening. I'm from Brazil. I got a pair of 9.2i kappa with damaged polydomes. First attempt I made, if the repair were to put a phenolic dome of the brand Snake model 3053, I did not like. Today I decided to use a small brain and I decided to try to make an EVA dome. I'm waiting for glue from the coil to harden and start testing.
     

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    Last edited: Aug 10, 2017
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  7. vinerp

    vinerp New Member

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    I'm testing. Very good sound.
     

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  8. okeeteekid

    okeeteekid Well-Known Member

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    Here is a video that I made of the RSDS polydome for anyone who has never seen one before.

    The video shows it next to an original and also shows the back of it up close.

    If we only knew 20 years ago that the polydomes were going to deteriorate we could have bought all these things up and had decent replacements, I bet a lot of them were installed in cars and ended up in the junk yard with them, what a waste.

    [​IMG]
     
    Last edited: Aug 12, 2017 at 8:01 PM
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  9. vinerp

    vinerp New Member

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    This EVA dome using original bobine and structure. Is a repair to original. Where I buy RSDS dome?
     
  10. okeeteekid

    okeeteekid Well-Known Member

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    If you get lucky they sometimes show up on ebay but they're not cheap. I've seen some that were in used fair condition sell for $300 plus a pair, in excellent condition/new like mine are in I've seen them sell for alot more and as our polydomes Deteriorate the price for the RSDS is only going to climb even higher, if you see a pair for sale I would grab them.
     
  11. 7.62

    7.62 Gearhead Subscriber

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    I'm just thinking out loud, I don't have the credentials to take on something like this. I do admire the guy that has done it with questionable material.

    In this day and age why nobody has embarked on a faithful reproduction or even better with UV inhibitors is interesting. Is the original material trademarked or forbidden to be reproduced or unknown ? I didn't go back and read all the posts and I may have said this before.

    It looks to me like the fella that sells the silicone repros didn't spend a life savings making the mold...etc. with the thousands of Infinity speakers out there with polydomes if someone were to do this and keep it reasonably priced, to me that's $50-$75.00 per unit, you could do pretty well both providing the service and making a profit.
     
  12. okeeteekid

    okeeteekid Well-Known Member

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    I agree with you, it's sad when you see people parting out their Kappa's because parts are no longer available to restore them, you see kappas that look like new sold for parts because the polydomes went bad.
     
  13. sagebug

    sagebug Member

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    What happened to the Chinese company that claimed it was working on the polydomes replacements? Same guys who are making the replica mids for the RS series, IIRC.
     
  14. slimpikkins

    slimpikkins Super Member

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    Let's hope something comes of this. The poly cone mid looked very impressive.
     
  15. okeeteekid

    okeeteekid Well-Known Member

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    I spoke with the guy 6 months ago through email and he said it was more difficult than they thought it would be to make the replicas, he said it could be another 1.5 years till they come out, if you could believe him.
     
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  16. goodolpg

    goodolpg AK Member Subscriber


    Thanks, wasn't even aware of those.
    I guess they are no longer made?
    Too bad given the number of original polydomes that have not aged well.
     
  17. 7.62

    7.62 Gearhead Subscriber

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    Ok, how did Infinity do it ? We're the originals made overseas ? Were they made here in the states, in house or subcontracted or sourced from several manufacturers and built in house, who was responsible for the speaker design itself and where are the working drawings for production, addendum for materials.

    I was reading in another area that someone has written about the history of JBL, again I'm thinking out loud but I often wonder why the history of Infinity has not been told in depth in a book form. There's bits and pieces all over the web but I'm unaware of a comprehensive in depth history.

    An old friend of mine, Lee Emerson did the history of the M14. I've often thought the same could be done with Infinity, is it a niche, yes. But one I think is worthy of the effort. Maybe collectively some of us could make the attempt, one of the original guys is in my neck of the woods ( Nevada ). Arnie & Bascom are still alive, we could gather data and start a compendium of facts while they're still available.

    That's my thinking out loud end. Sorry if I got a bit derailed there, it's been floating around in the Burroughs of my mind.
     
    Last edited: Aug 13, 2017 at 10:29 PM
  18. okeeteekid

    okeeteekid Well-Known Member

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    Infinity designed them at or about the same time our kappa's were made, don't know why they made them, next gen kappa? who knows but they wound up selling them for car audio applications.
     

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