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Wavebourn 7th November 2008 04:26 PM

How to glue Kapton?
Long time ago I read an article from some pre-WW-II magazine about construction of a planar loudspeaker.
It used a frame with a paper bent over, and a headphone which membrane was glued to the center of the paper.
I am going to repeat that experiment, but using modern components: motors from modern drivers, and a Kapton list. The problem is, which glue to use for Kapton, for the best adhesion? Is epoxy fine?
However, I can as usual experiment by myself, but I believe that the Forum Wisdom can help me to save some time; I am starving to finish and test the results ASAP. I believe that the construction is promising; the pros-contras of it are still to be researched.

ak_47_boy 8th November 2008 03:02 AM

I find it is hard to go wrong with good 24 hour epoxy. It sticks to virtually everything, and attacks virtually nothing. I have found general hardware store contact cement and adhesive tapes to creep under the diaphragm tensions. I would look into specialty adhesive tape if you want an alternative to epoxy.

SY 8th November 2008 03:51 AM

Why Kapton? It has pretty lousy acoustic properties (crinkly).

moray james 8th November 2008 05:39 AM

make a CA adhesive called Black Max which will bond kapton no problem, takes high heat (they bond disk break pads with it) and extreem vibration. Nasty stuff dont get it up your nose or fumes in your eyes it will make you sick so use a good fan.

el`Ol 8th November 2008 11:55 AM

The "Sumo Aria" was a commercial planar speaker that worked that way (with mylar diaphragm). The developers are both active here (Paul Burton and Moray James). They meant most of the development effort went into glueing.
My limited knowledge is that for polymers acrylate glue is as good as epoxy and has a hardening time of just a few minutes. Vibration stability is said to be better and there are versions that even glue PE or PP (which you donīt find in Epoxy).
My favourite material for such an experiment would be expansed graphite foil. My hope is that its polycrystaline structure would break up the wavefront and makes edge reflections unproblematic in the sense of a DML (distributed mode loudspeaker).

Sorry, just realized Moray already gave you the tip with the acrylate.

el`Ol 8th November 2008 01:40 PM

Concentration suffers today. I meant methacrylat, Moray meant cyanacrylat. I didnīt know there is cyanacrylat with increased mechanical stability, but if Moray says it works it schould be ok.

Wavebourn 8th November 2008 02:59 PM

Thank you!
I will try epoxy and cyanacrylate.

Here is the frame. Simple and cheap, but let's try it...

Speaking of cyanacrylate... Long-long time ago when I was a student, my roommate brought from internship on some military plant a bit of such glue... Jeans were symbols of a Liberty Statue, and were very expensive then (Import from U.S.A.!)
He used one drop offering guests to seat on a stool... Crazy, huh? :D

charles.david 4th December 2008 11:52 PM

Kapton = Hostaphan?
Forgive me for my ignorance but is Kapton the same thing called Hostaphan in other parts of the world and Mylar in others, or are they all different from each other? If they are what is the difference?

moray james 4th December 2008 11:58 PM

No they are not the same , here is some infor from Du Pont..

charles.david 16th December 2008 05:44 PM

thanks for the info. this helps a lot. :-)

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