Hi,
somehow I get the impression, that you do something, but not what is recommended.
The final stators are simple flat metal pieces. Installing a membrane and tightening it is the easiest of all designs.
what you need:
- the right film: I assume that You got that.
- the right glue: epoxy works, some PU-glues and even some double sided carpet tapes. You should test the glue joint on its strength and stability before.
- the right tension: This seems to be the problematic point here. So do it this way:
- With a pen draw a first set of marking lines on a flat surface (rectangle). Now draw a second set of lines with >1% to <1.5% larger dimensions. Lay down a piece of diaphragm film on that surface. Fix it with some sticky tape (a strip every 1"-2") so that it is just straightened (no tension yet). Mark the film exactly at the same position as the ´first´ rectangle on the flat surface with a pen.
Now start tensioning the film by pulling at the tape strips.
Work always in a crossed way fashion. You will have to do this several times (don´t try to get the final tension just in one go), thereby increasing tension in small steps to the final value. You are finished when the markings on the film reach the ´second´ larger marking on the flat surface. And don´t be astonished....the pulling forces will be quite high! Keep an eye on the ´corners of the film. Here the stress on the diaphragm material is very high. I recommend to put some sticky tape over the edges to reinforce these joints.
Then glue the stator to the membrane (You need a lot of pressure when working with ´wet´ glues like epoxy).
If your stator allows for (metal sheets normally do) you might glue strips of double sided sticky tape on the ´outside´rim of the stator sheet (~1/2" wide) before glueing the stator onto the film. This is especially useful when you use double sided sticky tape throughout!
Tape may give in to the tension over time. By making the ´contact area´larger it resists the pulling forces much better.
When the glue has dried, peel off the tape strips in a way that slowly reduces the tension on the film (it may tear otherwise).
Now peel off the lining of the double sided sticky tape and glue the film onto it with a good pull. Then trim the film along the tape edge with a very sharp knife or razor blade (You must not cut into the insulating of the stator though).
If You haven´t already glued the spacers into the stator You can now press some silicone dots at the right places through the stator holes. Keep in mind the 1/70 to 1/100 rule!
When the silicone drops have dried, turn over the stator and control Your work. The membrane should be axactly flat and levelled.
Now use a heat gun and start the heat treatment.
Work in a zigzag fashion over the membrane area. You can come quite close to the diaphragm (1"-2") with the nozzle but You shouldn´t be too slow in your waving motion (1Hz zigzag) or even stop at any point. You´ll see the membrane relaxing and retightening. The tension will be lower than before, but the stresses within the membrane will be reduced and more even. The membrane will settle very close to the final working point. This way results are more predictable, stable and with closer tolerances (Fs can be within less than +-2Hz).
When You´re done with this you can coat the diaphragm and install diaphragm contacting strips.
Do a second heat treatment.
Test the coating on function by connecting the HV-supply to the stator and membrane. You should see the membrane bowing towards the stator, but it shouldn´t touch it. If You worked cleanly (sweaty fingerprints are a proven method of generating invisible leakage paths

) the tickling sounds (which every panel exhibits at least at first start-up) should vanish within a couple of seconds to minutes.
If they don´t and/or the mebrane is pulled into the stator then You have to add more spacers to reduce the freely vibrating distances. The membrane tension would be too small in this case, so that the membrane comes too close to the stator so that the field density becomes to large and saturated and lowlevel flashovers occur (You could lower the polarizing voltage, but this cure should rather be no option here!).
When the test passed succcessfully, switch off the HV and lay the second stator on the first. Run the test procedure again!
When the test passed you can glue the two stator halves together and let them dry. Install the membrane and stator contacts (if that hasn´t been done yet).
You could do a third heat treatment if you wish, but the mebrane should have settled to its final working point already.
Now you should hold a working panel in your hands.....wasn´t that easy?
jauu
Calvin