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-   -   1/2 mil Mylar for ESLs (http://www.diyaudio.com/forums/planars-exotics/984-1-2-mil-mylar-esls.html)

phishead8 25th October 2001 06:43 AM

My current situation: I've finished my first pair of ESLs and ready to build another pair as a gift (as well as another pair for myself). I've got all of the neccessary parts ready to go, except the Mylar. I've tried repeatedly to get in touch with Barry Waldron, the supplier for my first batch, but have had no luck. He has not returned my emails for the past month, so it looks as if I'm going to have to look elsewhere. I've looked online for suppliers (thomasregistry.com) but have only found companies ready to sell industrial size rolls. I only need 20' and I don't want to pay for 150'. Does anyone know where to get a 20' length of Mylar? Anyone selling some from personal stock? If not, I'll have to just suck it up and blow $100 more than I want to.
Thanks.
-Dan

Jakeh 25th October 2001 10:16 AM

Dunno what width you need, and I can't be bothered to work out thickness from imperial, but just maybe..

http://www.surplussales.com/RF/RFTeflon-Mylar_sht.html

Petter 25th October 2001 10:41 AM

Teflon
 
Which brings us to an interesting question: Is Teflon film actually better?

How about the Kapton film?

Petter

dufre 25th October 2001 01:51 PM

The pages of Barry Waldron have moved to http://www.eslinformation4u.com/
Look around there, apart from a lot of ESL info, also the address of Barry.

By the way, take a look at the DIY-ESL forum at delphi:
http://www.delphi.com/ESLForum1/start
Barry is one of the members.

Succes with your ESL's!!

Fré

phishead8 25th October 2001 04:32 PM

Jakeh,
The Mylar you've pointed me to is about 10 times too thick. I need 1/2 mil, but maybe the Kapton Mylar would work. Of course, it is a $75 test... Thanks for the link, though.

Petter,
I haven't tested any of the other films, but I don't see why they wouldn't work. As far as I can see, the only parameters of the membrane that affect sound quality are tensile strength and weight/density. The membrane doesn't need to have any electrical qualities (as far as I can tell). But, as far as construction goes, the Mylar's heat-shrinkability helped alot. Imperfections in my construction were whisked away with a wave of the heat gun. Magic.

dufre,
I've been to Barry's new page, but his email has not changed since the summer and my first order. I don't see why I am having trouble finding him. Thanks for the DIY-ESL forum. I will definitely try to find Barry there. It seems that he's recently made a post. Hope abounds.


Thanks everyone
-Dan

Jakeh 25th October 2001 05:36 PM

You could ask them to split a roll, they seem to happy to do so with the other types...

or http://www.consemp.com/catalog/m.html

phishead8 31st October 2001 11:19 PM

Thank you, Jakeh. What a wonderful supply. Have you checked out the Hollytex and Dartek that they sell? I asked them to send me some samples of the material to see what mysterious properties they contain first-hand. But, I'd still rather get my Mylar from Mr. Waldron, simply becuase I've heard it in action and I'm satisfied with the results. I'm also not sure if Barry sells Mylar "D". DuPont apparently makes all sorts of different types of Mylar, complete with different properties, however subtle. Most 1/2 mil Mylar that I see being sold is Mylar "D". Is this the same stuff that Barry is peddling? I can't find out simply because I still can't get ahold of him. Catch-22.

-Dan

Hedlund 1st November 2001 05:09 AM

12 or 10 my Mylar film
 
I have got two rolls of mylar film that can be used for electrostatic loudspeakers.
None of them can be stretched with heat though.
But it's better if you can control the stretching instead of make final adjustments with a heat-gun which will give a very uneven tension.

I'm dropping my electrostatic project and if anyone is interested I will sell both rolls at a low cost.
Each of them contains around 100000 meters of film.

/Janne

phishead8 1st November 2001 04:42 PM

Hedlund,
What type of Mylar are you selling? Is it 1/2 mil DuPont made Mylar? Or another type of PET film. I haven't heard of DuPont Mylar that doesn't heat-shrink, but there is alot that I don't know. "100000 meters"?? I don't think that my house is large enough for that. How big are these rolls? And how much are you willing to let the go for? Perhaps I can buy just 30 meters.

As for the heat-shrinking, I've found it the easiest way to tension my speakers. The Mylar that I bought from Barry was accidentally pre-shrunk in the mail (I had bought the stuff in the middle of summer). I tried the stretch and tape method of tensioning, but a large crease ran down the middle of the film. I simply could not pull hard enough to get the crease out. This crease was complete with loose spots around it that would not comply to audiophile standards. It looked hopeless. To alleviate the problem I sloppily glued the Mylar in a frame that was just a bit larger than my stator. I waved the heat gun over the Mylar till the crease had dissappeared. The entire surface became tight and even. Coating with graphite was a cinch. Glueing required no effort, just apply epoxy and lay the stator/spacers on the film in the frame. The speaker came out beutifully. Afterwards, I used the heat gun again to make sure everything was even. Here's the beuty of it: the Mylar only shrinks to a certain tension, then stops. While I have no control over said tension, it is even as can be, over the entire speaker. The resonance of the speaker turned out to be ~120 hz, low enough to make me happy. I suggest this same technique to anyone who is discouraged by the stretch and tension method.

-Dan

Hedlund 1st November 2001 08:02 PM

Dan,

It's normal polyester film = Mylar which I bought from Rifa (the capacitor producer). The products name is Hostaphan and works very well for electrostatic loudspeakers.
The surface seems to be pretreated for metallization, and this makes it very easy to apply the conductive liquid, or graphite powder you use to make the film conductive.
The thickness is given in my = 1/1000 of a millimeter which equals 1/25400 of an inch. My film is as said 10 or 12 my which will be 10 or 12/25400 inch = (approx) 0,00043 inch which I assume is 0,43 mil if I understand your measuring standard correctly.
Let me know if I don't, cause I'm a millimeter man myself.

30 meter mylar costs 15 cents which equals $20 US including my work and shipping from Sweden.

>How big are these rolls? And how much are you willing to >let the go for? Perhaps I can buy just 30 meters.

They weights around 40 Kg each. 30 meters is OK as long as you accept the price above.

I think you will get a better result if you don't use shrinkable mylar. Just use/build a good tensioning rig.

/Janne


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