Hi ...
This is what Calvin wrote to me in an earlier PM. Since Calvin normally is very "helpfully informative" I take the liberty of posting this here:
.....
Additional links with infos about materials and techniques (also from Calvin):
http://www.diyaudio.com/forums/planars-and-exotics/109789-esl-diaphragm-coating-29.html#post2054671 (coating joint failure)
http://www.diyaudio.com/forums/planars-and-exotics/109789-esl-diaphragm-coating-5.html#post1355038 (double-triple coating)
http://www.diyaudio.com/forums/planars-and-exotics/93444-conductive-coatings-2.html#post1100162 (coating technique)
http://www.diyaudio.com/forums/planars-and-exotics/109789-esl-diaphragm-coating-29.html#post2053289 (consistence and application)
Courtesy Calvin.
Cheers,
Jesper
This is what Calvin wrote to me in an earlier PM. Since Calvin normally is very "helpfully informative" I take the liberty of posting this here:
.....
Additional links with infos about materials and techniques (also from Calvin):
http://www.diyaudio.com/forums/planars-and-exotics/109789-esl-diaphragm-coating-29.html#post2054671 (coating joint failure)
http://www.diyaudio.com/forums/planars-and-exotics/109789-esl-diaphragm-coating-5.html#post1355038 (double-triple coating)
http://www.diyaudio.com/forums/planars-and-exotics/93444-conductive-coatings-2.html#post1100162 (coating technique)
http://www.diyaudio.com/forums/planars-and-exotics/109789-esl-diaphragm-coating-29.html#post2053289 (consistence and application)
Courtesy Calvin.
Cheers,
Jesper
Quote:
Originally Posted by wout31
I found Licron Crystal unusable in my project, the Quad ESL-63.
How so, when many have posted successful outcomes ?
1. The resistance is too low (for the Quad ESL-63 that is)
2. It holds very little to no charge (when I discharge th membrane to ground there is next to nothing)
3. The resistance fades in a very short time. Days to weeks.
4. Almost impossible to spray evenly on the Mylar with the spray can
5. Can be rubbed of very easily with several solvents. All your resistance is gone.
Jos Wouters
Originally Posted by wout31
I found Licron Crystal unusable in my project, the Quad ESL-63.
How so, when many have posted successful outcomes ?
1. The resistance is too low (for the Quad ESL-63 that is)
2. It holds very little to no charge (when I discharge th membrane to ground there is next to nothing)
3. The resistance fades in a very short time. Days to weeks.
4. Almost impossible to spray evenly on the Mylar with the spray can
5. Can be rubbed of very easily with several solvents. All your resistance is gone.
Jos Wouters
Quote:
Originally Posted by wout31
I found Licron Crystal unusable in my project, the Quad ESL-63.
How so, when many have posted successful outcomes ?
1. The resistance is too low (for the Quad ESL-63 that is)
2. It holds very little to no charge (when I discharge th membrane to ground there is next to nothing)
3. The resistance fades in a very short time. Days to weeks.
4. Almost impossible to spray evenly on the Mylar with the spray can
5. Can be rubbed of very easily with several solvents. All your resistance is gone.
Jos Wouters
I've built quite a few speakers with Licron Crystal over the past eight years or so when I started using it. Fortunately, my experience with it has been mostly positive.
By mostly positive I mean that it's always yielded high output, but one can I purchased had low propellant pressure; causing it to sputter out of the nozzle and I had to shake the can while spraying and apply a second coat to cover the light spots-- even then, the dried coating yielded excellent output, which is the most important consideration.
I found that it will fisheye over any fingerprints or other contaminants on the Mylar, so I always clean the Mylar first, using a cotton swab and alcohol. And if applied on a rainy day it will blush and dry cloudy (but no effect on output).
One other tip: As purchased, a full can of Licron Crystal is actually about half empty. So, I found it helpful to position the panels at about a 45 degree vertical angle for spraying-- so that I don't have to tilt the can, which can cause the pick up tube inside to draw in propellant with the liquid, and result in sputtering.
Every time I've used Licron it it has adhered well to the Mylar and yielded high output, and I haven't detected any loss after several years. When I say it adheres well, I evidence that by noting it's difficult to scrape of the dried coating with a fingernail.
Other than your report, the only other time I've hear of anyone having problems with Licron is when they diluted it with added solvents and rubbed it on with a swab, in an attempt to reduce its thickness and mass.
Also, I've never rubbed a dried Licron coating with a solvent (nor would I)-- but your report that it isn't solvent resistant is, I would think, to be expected.
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Quad ESL-63 graphite coating
Hi CharlieM,
You may be right for your DIY speakers, but I'm talking about Licron being applicable for the Quad ESL-63 and it stops at the first item: To low a resistance. 10^7 at best and not evenly equal over the surface. And one of the items Jesper mentioned was he wanted 10^11 - 10^12 for resistance.
So I developed my own graphite coating over the last 2 years after some major disappointments in "professional" high cost restoration on my Quads.
I can make the coating any value I want (also 10^11 - 10^12, I can measure up to 200 Gig per square at 5 kV).
Never heard a Quad ESL-63 set sound like it sounds now with this coating. But beware it is not only the coating, there is much much more to take care of.
No the coating is not commercially available and never will be because of reasons I mentioned in an earlier post. Hazardous, very unstable until applied, so has to be applied within 2 hours after mixing. All items in the chain matter for your coating. Resistance value could go in any direction from 10^3 to infinite and everything in between. I think that is why some people stopped selling their coating, because you can give no guarantee that it will be mixed and/or applied in a proper manner and hence works like it should and could work. People will brag on the sales of their speakers that they were prepared with XYZ coating and therefore are the best buy. It can ruin a company's name if the applier made mistakes or was just too impatient.
It took me over 400 tests and close to a thousand dollars in materials over those 2 years before I found a solution. The result in sound blew me away. Just very lucky I think.
Hi CharlieM,
You may be right for your DIY speakers, but I'm talking about Licron being applicable for the Quad ESL-63 and it stops at the first item: To low a resistance. 10^7 at best and not evenly equal over the surface. And one of the items Jesper mentioned was he wanted 10^11 - 10^12 for resistance.
So I developed my own graphite coating over the last 2 years after some major disappointments in "professional" high cost restoration on my Quads.
I can make the coating any value I want (also 10^11 - 10^12, I can measure up to 200 Gig per square at 5 kV).
Never heard a Quad ESL-63 set sound like it sounds now with this coating. But beware it is not only the coating, there is much much more to take care of.
No the coating is not commercially available and never will be because of reasons I mentioned in an earlier post. Hazardous, very unstable until applied, so has to be applied within 2 hours after mixing. All items in the chain matter for your coating. Resistance value could go in any direction from 10^3 to infinite and everything in between. I think that is why some people stopped selling their coating, because you can give no guarantee that it will be mixed and/or applied in a proper manner and hence works like it should and could work. People will brag on the sales of their speakers that they were prepared with XYZ coating and therefore are the best buy. It can ruin a company's name if the applier made mistakes or was just too impatient.
It took me over 400 tests and close to a thousand dollars in materials over those 2 years before I found a solution. The result in sound blew me away. Just very lucky I think.
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@wout31: Well, it sounds indeed as if you have really given this topic some attention and time ... congratulations on getting at such a fine result!
However, when reading what you write (at least) one question pops up - can you say what the weight would be of a coating of yours with a resistance of 10^12 (in mylar microns ;-) )?
Cheers ...
Jesper
However, when reading what you write (at least) one question pops up - can you say what the weight would be of a coating of yours with a resistance of 10^12 (in mylar microns ;-) )?
Cheers ...
Jesper
The thickness adds 100%, so the 3 micron become 6 micron. Sometimes 7 micron at most (see 3 micron Mylar below). I measure it with a thickness meter with a spring pusher that always puts the same pressure on the Mylar. So no multiple folding with risk of error, but just one sheet is measured.
The weight adds 30% to the original weight of 4,3 grams per m2 for 3 micron Mylar. I measure this with a special digital jewellery scale that is accurate to 0,001 gram. After applying the coating I take a piece of 20x20 cm and multiply the weight to get to a square meter. I also do a before and after measurement, because 3 micron Mylar is not always 3 micron, but can often be 3,5 micron and than the base weight is 5 grams per m2. Depends on your source for Mylar material.
Jos Wouters
The weight adds 30% to the original weight of 4,3 grams per m2 for 3 micron Mylar. I measure this with a special digital jewellery scale that is accurate to 0,001 gram. After applying the coating I take a piece of 20x20 cm and multiply the weight to get to a square meter. I also do a before and after measurement, because 3 micron Mylar is not always 3 micron, but can often be 3,5 micron and than the base weight is 5 grams per m2. Depends on your source for Mylar material.
Jos Wouters
Hi MJ & CharlieM,
@MJ Dijkstra: Can you just briefly say (or point me to a link) where possible advantages of the HTEC coating vs. the TESA glue is described? I would be most interested in reading about this ...
Cheers & thanks again both of you
Jesper
Hi Jesper,
HTEC-coating doesnt rely on the humidity of air while most high resistance coatings do. It is also low mass. I do have a balance which allows me to accurately measure tenths of a milligram; it turns out the mass of this coating is below 1 micron of Mylar. Thick coatings not only may impair high frequency response but also will become less flexible and may crack or flake off as a consequence. Another aspect is chemical stability. Conditions of light (near a window) and ozone may attack chemical structures and consequent loss of conductivity depending on the mechanism of conduction.
TESA will have varying conductivity depending on temperature and humidity. It is already on the high scale of resistance so a further increase may result in entering the 'danger zone' in which the ESL is not capable to completely charge. Adding graphite particles to increase the conductivity of TESA is not a good idea in my opinion. In fact graphite-particles is about the worst substance to make a high resistance coating.......just my 2 cents
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Hello Jos,
Are you sure your numbers are correct? If your coating ads 30% of the original weight of 3 micron Mylar it corresponds to a mass of around 1 micron of mylar. But the thickness according to your measurement is at least 3 micron. This means density is about 1/3 of mylar maximum which is lower than all other plastics I know of. It is even more surprising as the addition of carbon increases density. Carbon loaded plastics are quite dense, most of them won't even float, which is no surprise as graphite density is above 2,0!
Heej Jos also here 
Well if i might chip in, the calvin coating, you can use liquetex and a dozen of other carbon based inks. (PB7 pigment) still they dont rock to be honest, a bit hit and miss. also the glue coating is a failure , it works..... for some time.
Then i saw someone mentioning lycron crystal (the new one) not working for quads esl63. well yess and no Lycron did nt work for me since it disappears after a while. but the resistance is 10 times or more then the original coating resistance. something i hear little to no complaints about. at least it stays there for ever. the old lycron had more potential to work for a long period compared tot he sort of conductive polymer based stuff in my opinion. i dont like shelf life and random results to be honest. the old lycron used ITO for sure, the new one...... i think A polymer. at first it thought they used ITO since i read the datasheet but apparently it was the old lycron datasheet. im still looking for a decent coating to for the ESL63 still got 2 sets sitting here doing nothing
Well if i might chip in, the calvin coating, you can use liquetex and a dozen of other carbon based inks. (PB7 pigment) still they dont rock to be honest, a bit hit and miss. also the glue coating is a failure , it works..... for some time.
Then i saw someone mentioning lycron crystal (the new one) not working for quads esl63. well yess and no
Lycron did nt work for me since it disappears after a while. but the resistance is 10 times or more then the original coating resistance. something i hear little to no complaints about. at least it stays there for ever. the old lycron had more potential to work for a long period compared tot he sort of conductive polymer based stuff in my opinion. i dont like shelf life and random results to be honest. the old lycron used ITO for sure, the new one...... i think A polymer. at first it thought they used ITO since i read the datasheet but apparently it was the old lycron datasheet. im still looking for a decent coating to for the ESL63 still got 2 sets sitting here doing nothing
i think we talked about this but i think using a multiple of folds of a membrane does decrease fault margin more then it adds to the fault. since the thicknesses are so small and most use Chinese scales and such. it is a simple method to increase thickness to get rid of the fault margin of Chinese equipment. just my 2 cents. also a lab scale is expensive for a reason i believe, and has shielding all around it etc etc (glass) even some air might change the scale at these low weights.
Measurements thickness and weight
M.J. Dijkstra,
Yes the numbers are correct. 100% extra thickness (3 micron) adds only 30% in weight. I can't make it any different to what the scale and the thickness meter reads.
Don't know if it makes any sense? I just read the scales. Checked it again to make sure. The weight gets higher with lower resistance. 10^10 adds 50% weight. But yes, 10^12 only adds only 30% weight.
I can't measure any variation in thickness between 10^10 and 10^12. Probably because it is within 1 micron and I can't measure more accurate than 1 micron. Maybe it is 5.8 and 6.4 or something like that, but all reads 6 micron with my measurement tool.
On the Licron matter I re-tested to make sure I was informing correctly.
Measures 80 Meg on all voltages. Leave for 24 hours to dry, wet you finger and move it gently over the surface, only 30 Meg left! Me recollection was correct. No solvents needed, a little bit of moisture does the job to lose almost half of the resistance.
M.J. Dijkstra,
Yes the numbers are correct. 100% extra thickness (3 micron) adds only 30% in weight. I can't make it any different to what the scale and the thickness meter reads.
Don't know if it makes any sense? I just read the scales. Checked it again to make sure. The weight gets higher with lower resistance. 10^10 adds 50% weight. But yes, 10^12 only adds only 30% weight.
I can't measure any variation in thickness between 10^10 and 10^12. Probably because it is within 1 micron and I can't measure more accurate than 1 micron. Maybe it is 5.8 and 6.4 or something like that, but all reads 6 micron with my measurement tool.
On the Licron matter I re-tested to make sure I was informing correctly.
Measures 80 Meg on all voltages. Leave for 24 hours to dry, wet you finger and move it gently over the surface, only 30 Meg left! Me recollection was correct. No solvents needed, a little bit of moisture does the job to lose almost half of the resistance.
thickness
Hoi Joppe,
I calibrate my thickness meter with 4 thicknesses of Mylar.
2 micron, 3 micron, 6 micron and 12 micron. If the thickness is not as specified, my meter is wrong as well. But ALL 4 read the correct thickness with the meter. So I trust it reads the thickness with coating added correct as well. With folding IMO the risk of wrinkling is at hand and therefore the margin of error. But maybe both ways work evenly correct if done properly. We all work with the best affordable meters which is definitely not always laboratory grade in my case. I use the meters to get a direction of where I'm going, not as a pure grade quality statement.
Hoi Joppe,
I calibrate my thickness meter with 4 thicknesses of Mylar.
2 micron, 3 micron, 6 micron and 12 micron. If the thickness is not as specified, my meter is wrong as well. But ALL 4 read the correct thickness with the meter. So I trust it reads the thickness with coating added correct as well. With folding IMO the risk of wrinkling is at hand and therefore the margin of error. But maybe both ways work evenly correct if done properly. We all work with the best affordable meters which is definitely not always laboratory grade in my case. I use the meters to get a direction of where I'm going, not as a pure grade quality statement.
About your licron experiment; you lose resistance? Well I think you are increasing conductivity by adding moisture which I think is a normal thing to happen. Remember your wet finger also contains dissolved salts etc.
I use a calibrated analytical balance (a Mettler) with glass screening. This is the kind of equipment which you can do truly accurate measurements. Unfortunately this is expensive stuff.
Hi all,
Very interesting discussion & information I would say - & thanks to MJ (I hope it is ok that I call you this?) and Jos for clarifying ;-)
About the Chinese scales I have one myself, and although I would guess that it is not as precise as a genuine laboratory scale on the other hand my experience with it would suggest that the error is in the low percentage region. Thus, usable in my context (yet of course it likely is different from the scales you have).
I am currently layouting a DAC board so have my focus elsewhere but hope to look back here in not too long.
Cheers,
Jesper
Very interesting discussion & information I would say - & thanks to MJ (I hope it is ok that I call you this?) and Jos for clarifying ;-)
About the Chinese scales I have one myself, and although I would guess that it is not as precise as a genuine laboratory scale on the other hand my experience with it would suggest that the error is in the low percentage region. Thus, usable in my context (yet of course it likely is different from the scales you have).
I am currently layouting a DAC board so have my focus elsewhere but hope to look back here in not too long.
Cheers,
Jesper
M. J. Dijkstra,
The calibration of my 0.001 gram scale is the same as my thickness meter. If I weigh a surtain amount of Mylar of a specified thickness and the result is the weight per M2 as stated by the manufacturer with all 4 thicknesses I can assume that the weighing of the Mylar with coating is also correct. Maybe it has a fault of x percent, but still 30% weight increase will not become 300%, maybe 32% or 28%. But as I mentioned before I just want an indication, not a spot on measurement. So I don't need a laboratory scale to tell me ballpark I'm in. Good enough for me.
Jos Wouters
The calibration of my 0.001 gram scale is the same as my thickness meter. If I weigh a surtain amount of Mylar of a specified thickness and the result is the weight per M2 as stated by the manufacturer with all 4 thicknesses I can assume that the weighing of the Mylar with coating is also correct. Maybe it has a fault of x percent, but still 30% weight increase will not become 300%, maybe 32% or 28%. But as I mentioned before I just want an indication, not a spot on measurement. So I don't need a laboratory scale to tell me ballpark I'm in. Good enough for me.
Jos Wouters
Stripes? It is spray painted.
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