Other ESL build with simple materials available from local grocery stores

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Hi,
This is my virgin thread, I hope I didn't step on other threads on this subject.

I am presently collecting materials for my ESL. I wish to experiment with a small prototype before proceeding into fullrange and high SPL.

I had many restraint in allocating commonly suggested materials for ESL, especially bulky materials which will cost both me arms and legs to ship.

This is how far I had progressed,
The film:- there are no other alternative other then mail order some 6um mylar film,
Insulator:- Plexi glass seems to be the default material for insulator in my location as many thickness can be obtained easily,
##PS, small items shipping cost is ok.

Transformers:- The bias supply can be made easily using common EI step down transformer, the matching OPT needs more thought but can be arrange.

Stator:- Perforated plates are not off-the-shelf item in our local hardware store. Wire stators seems extreamly labour intensive and quality solid core copper wires are rare commodity.

I happened to come across some fine mesh metal mosquito nets and other stainless steel wire mesh for filter.

Question:
I wonder if we can fine mesh metal wire nets as stator conductor by glueing them onto the lighting grates, egg crates or other form of support for mechanical strength?


Cheers
 
Hi, Audio_idiot.

The wire screen is an interesting product for stators and I haven't seen it used before. You will not have to deal with the problem of sharp edges like perforated material, but I wonder if all the wire ends on the screen will give you a leakage problem.

As you're finding out, getting materials for an ESL is one of the biggest challenges a DIYer faces. I had to order parts from three different places just to build new HV bias supplies.

Bigwill writes: Will cling-film or 'saran-wrap' work for the diaphragm?

In addition to what SY wrote, the cling film seems too 'soft', especially if you're going to use graphite on it. I've got a package of window insulating film that I bought for the double sided tape inside. The film measures 0.005" thick, about 12 micron and is heat shrinkable. It's a bit thick, but if it's available in your area, it may be worth looking into.

Audio_idiot, you'll probably find that your ESL design will evolve as you build according to the materials available. Please let us know how it works out.
 
Hmmm, I just tried to heat-shrink some cling film and it worked nicely, and it seemed to be pretty strong and robust. You could poke it about a lot and simply apply heat again to get rid of the crinkles. You had to stretch it a lot to make it unable to go back to its original shape leaving permanent creases. I think it would be strong enough to apply graphite to, and any "dents" you put in it whilest doing so can just be heated again. The stuff felt light enough to produce high frequencies, but that's an entirely intuitive feeling not an actual fact..
 
Hi,
If you want to experiment , a thin baking film may be easy to get , and usually comes in around 12 um thick. A black shoe wax may work for coating :).Shoe wax is soluble in water , so it is easy to apply a thin layer of it.
Wire mesh is possible to use for stators , however , it might be hard to insulate it well , like perforated steel. You will have to glue it on support structure , which will not be that easy.
I'd suggest the wire method. It is not the cheapest , and consumes lots of time , but you can build a quality panel. PVC insulated or magnet wire is not difficult to get.To stretch the wires succesfully , you would need a jig. It can be built from threaded steel rods on a wooden frame.The louvers are placed between the rods.The wire is then wound on both stators at once. Then , the wire is additionally stretched. The next (and probably the most time consuming) step is glueing the wires.
Trying to build ESL in a fast way is very likely to result in failure.

Regards,
Lukas.
 
Hi,
Thanks for the great responds, I wouldn't mind trying out on Cling film for a start, I feel that it's much more importnt to get the engineering correct before we venture into more ideal materials. Shoe wax on cling film is most attractive! Love to see the face of my friends when I told them what the ESL are made from!!! :)

I looking into combination of wire and perforated plate stator construction...

I recon we can stratch/tension the mesh using the bicycle tube stretch table and the glue the mesh on the louvre. Then apply the glue over the whole mesh with a roller brush (just like painting over em) so that the glue will double as insulator as well. Do you think this is workable?

As for the openings, I read somewhere in this forum that there are no fix and fast rule on %tage of the opening... thus, I think anything which i can blow a breath through without much restriction is goo enough... like i say, all depand on what I can get at my local hardware store. I also feel that finer wires of the wiremash cross knitted can provide a much even/stronger static field the wire or perforated stator...

BillH, I feel that the leakage problem will be worse in wire mash as the ends as all pointy sharp thin wires which is the most coducive environment for leakage to occur... but can we some how close that out???

Another question on the wire stator, will the louvre stay static after power down?? and give a unsuspected shock to anyone toucing em? as plastics can store some static charges...

Cheers
AI/
 
You can make do without fancy jigs to string your wire on polystryrene louvres from flourescent lights. Just use small cable ties at each end to hold each loop of wire.

I used plexiglass strips for the spacers. You can just see the cable ties behind the spacer at the end of each loop.

The wire is teflon-coated 30 gauge wire-wrap.

After stretching the wire tight I held it to the louvre with dots of epoxy. Once the epoxy was dry I cut cut the cable ties off.
 

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I have a whole roll of brass screen that I haven't got round to trying yet. I'm not worried about leakage because the screen is on the outside of the spacers, away from the membrane.

Not to worry about residual charge on the membrane. The resistance is about 100k ohms and the voltage bleeds off over 4-5 minutes.

Cheers.
 
Hi guvasta,
The spacing between wires looks very far apart... Helps with speed of construction.

What do you mean when you said "each loop of wire" , I was in the impression that the wire stator is made out of a single length of wire.

Thanks for the pix, looks much easier then I thought.

Cheers
 
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