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-   -   How thick for MYLAR??? (http://www.diyaudio.com/forums/planars-and-exotics/62850-thick-mylar.html)

Dominick22 20th August 2005 12:20 AM

How thick for MYLAR???
 
The following is in regards to building a homemade ESL panel...

I have seen mylar from 1 mil to 5 mil thick and then I read an article that recomended 5-6 microns thick. What do I want to buy? On ebay they all appear the same, but on DuPonts website, they have coated and uncoated and a ton of other options. What is the best way to go???HELP PLEASE

Calvin 20th August 2005 05:07 AM

Thickness
 
Hi,

choose the thickness after Your needs! It depends on what You want to achieve. If You want to build a fullrange ESL You may use up to 0.5mil (12). If You want to build a hybrid like ML (with very high mechanical tension) use a film between 1/4 and 1/2mil. If You want to build a hybrid with lower mechanical tension You may use a film down to 1/8mil. You want a Bass-Panel? You may use up to 1mil. Films with thicknesses of more than 1/2mil will have problems to perform up to (and over) 20kHz. The best compromise seems to be around 1/4mil. Here the strength of the film is already high enough to withstand even high mechanical tension, on the other hand it is so lightweighted that it performs well up to and above 20kHz.

jauuu
Calvin

wrl 20th August 2005 05:46 AM

Hello,

I purchased the mylar for my speakers from

www.eraudio.com.au

just check under "components". I think that I purchased the 3.8 micron and have so far been very happy with it. I can't remember the exact tension I applied (something like 4-5 lbs) during construction, but I use a hybrid set up with 8 inch woofers.

Although the company is from australia and shipping is more difficult than in the States, I have been very happy with their service. I'd email them and ask what they recommend. I'd have no reservations ordering more from them.

They even send me a Christmas (or I guess Holiday to be P.C.) card every year :)

Anyway, hope this helps... best of luck with your project.

-Wes

michaelpage26 20th August 2005 01:26 PM

Yeah their service is excellent. I live in Greece and I will be buying the ESL 3 kit from ER-audio, so I asked Rob if he could send me a small sample of the 3.8 micron diaphragm. Well he sent me for free 10 meters of it! :bigeyes: :bigeyes: :bigeyes:

I_Forgot 22nd August 2005 07:29 PM

Quote:

Originally posted by wrl


I can't remember the exact tension I applied (something like 4-5 lbs) during construction, but I use a hybrid set up with 8 inch woofers.


How did you tension the film, and how did you measure the amount of tension?

Thanks,

I_F

wrl 24th August 2005 06:12 AM

With an oversized piece of diaphram laying flat on my work surface, I attached a piece of packing tape to the excess boarder of the mylar. The other end of the tape was than attached to a formica sample piece (the smooth kind...not the bumpy kind) which was in turn attached to a 3 dollar fish scale from walmart. ;)

After pulling to the correct tension I removed the tape end from the formica and stuck it down to my work surface (essentially locking in the tension)

I started at each corner and then did the center of each side. Then I did the center of each new division until all of the wrinkles were out. Then I redid the corners. This mechanical tensioning is less troublesome for first timers than heat shrinking. I have made several panels this way and haven't had any problems so far. I used foam tape to attach the diaphram to the stators. I got this idea from Sheldon who has some good info on his site

www.quadesl.com

Anyway, hope this helps... if you need more info I can try and write up something more specific.

I_Forgot 26th August 2005 02:25 AM

So after tensioning the film on the work surface, you apply foam tape to the stator/insulator and stick it down on the tensioned film?

What sort of foam tape are you using? Is the foam tape the only insulation between the stators? When did you first make the drivers this way? Do the first drivers still work?

What are the insulator thickness and bias voltage you are using?

What sort of conductive coating do you apply to the diaphragm?

Thanks,

I_F

wrl 27th August 2005 07:26 AM

1) I used the black conductive coating from ER audio.

2)Yep, I just placed the panel/tape assembly right on top of the tensioned mylar. I used 3M foam mounting tape that was 1/16 of an inch thick.

So it goes like Stator:foam tape:mylar:foam tape:Stator.

I think I got a large role (~50 ft) from misterart.com I used perforated aluminum sheet metal for the stators which I then coated with many many thick coats of rustoleum pain to provide some insulation. The foam tape is the only spacer/insulator between the diaphram and the stators other than the paint.

3) I'm not sure of the exact bias voltage I'm using becuase I made it adjustible from 0-4000V. If I had to guess I'd say its probably about 2000-2500V bias

4) The overall setup is similar to the hybrid setup provided in Roger Sander's "The electrostatic cookbook"

-Wes

I_Forgot 28th August 2005 03:37 AM

My experiece with foam tape is that it dries out and crumbles to dust in a about a year when exposed to air/light. Are you using some special tape?

What are your oldest panels that use that tape and are they still working?

Thanks,

I_F

wrl 28th August 2005 05:41 AM

I don't think the tape was anything special... just standard 3M foam mounting tape.

So far my panels are almost 2 years old and I haven't had any problems yet. I built them in New Mexico (very dry) and then moved them here to St. Louis (ridiculously humid) and it didn't seem to hurt anything. I haven't used them in a while though because I'm rebuilding the bass cabinets. The tape has yellowed slightly but appears to be in good condition otherwise.

In anycase, because the panels are removable from the frames it would only take a weekend to rebuild them. And I usually get enough new ideas to want to try something new with them every few years anyway.

-Wes


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