Dropping efficiency coating ?

[alexberg]

Originally Posted by Capaciti

Hi,

i am wondering people telling you about just using some black ink to dope. There is no carbon black in black ink used for writing !! I measured several types of black ink, and never were able to measure some conductivity.

Possibly people dope for having a "good feeling" , but nobody here has proven, means provided measurement readings of black ink.

Folks, before going on suggesting any black ink, tell us about the specific brand, for which you were able to confirm conductivity !

BTW: You can try out different kind of PVA glue. All of them need humidity to work. It depends on the final surface roughness how much water molecules are attracted by the PVA-Layer. Possibly there are types of PVA glue which provide an appropriate layer to attract enough Water, while others dont do. PVA is not conductive.

Capaciti

Absolutely,
in order to get conductivity in non-conductive matrix, the amount of carbon black shall be... substantial...
Most printer inks use coated carbon particles - simpiest way to check it is to measure resistance of the printed line - no luck so far.
Quite expensive china (indian) writing ink did not work either
Use graphite or specifically designed dissipative coatings. The latter ones are pricey, shelf life is limited; resistance, however is reproducible,
adhesion is proven and specified in tds by manufacturer.
The one I've got is based on polyanilin (my guess): resistance depends on temperature - measured the value during heat treatment.
Sincerely,
Alex

[bolserst]

Originally Posted by Capaciti

i am wondering people telling you about just using some black ink to dope. There is no carbon black in black ink used for writing !! I measured several types of black ink, and never were able to measure some conductivity.

I have tried 6 different black inks, including the often recommended India Ink. None seem to improve or change the conductivity of a coating once dry. As a final test, I drew thick black lines on mylar with each of the undiluted inks and let them dry completely with the help of some warm air from a small personal heater. Once dried, none of the black inks were conductive at all. Of course, before the ink was completely dry there is some conductivity.

Perhaps there was one particular black ink that someone found that DID have conductive properties and that was the root of the recommendation for black ink doping.

[WrineX]

well i finally after 2 days of aplying and removing caotings, i ended up with a coating with wich sucked my membrane to the stator,

this are the mixtures i tried.

- velpon glue and water, works but not that good whas not able to suck my membrane to one side.
- Ink velpon and water. my experience whas after mesearuments a bit higher output but still not that high.
- ink and velpon no water. did increase output but looks black and verry ugly end gets messy.
- velpon water aplyd after that rubbed in graphite. if people like graphite this is the way to go to applly need almost no graphite sticks verry wel and after rubbin in ytou get some silver mirror, but for me way to low resistance of 300 ohm happens to be the resistance of the earlier solosound panels.

- and now the mixture that worked best for me is


think there is room to bumb up the water so it will get a thinner layer. but for now it workes for me.
velpon , water, and washing soap used 10ml water 3 drops velpon and 4 drops dreft.

only one layer whas enough, if its complete dry it does not stick and its transparant, only from side you see in direct light rainbow colors . sucked my membrane to stator directly (to low res freq for small pannel) so lowerd voltage but got more output then any other solution used by me.

[Ulf Eliasson]

No luck with ink but antistatic vinyl polish works excellent
See this post
I'm started today testing with polish only and the speakers have never sounded better, but the question is how long it will last.

[WrineX]

yeah that remains a thing here as well, i leave my setup for now, and measure everyday to look what happens. for now past 5 hours, it just goes a little up and one minute later a little down. stays pretty stable

[geraldfryjr]

i figured the ink thing was a farse.as i have yet to find one that is conductive unless it stated as such,including ones that were metalic.i must have spent a small fortune on different kinds of inks.
the only thing that i have found to readily work as a conductive paint is graphite, as i don't have a source for super extra finely ground powdered metal.
I'm wondering if another type of metal oxide could be used such as iron oxide.it is conductive,easy to make and not so poisenous as tin oxide or indium oxide and dissolves in water easily. jer

[chinsettawong]

Hi,

It's interesting to hear from many of you that you can't measure the resistance from the dried black ink. I'll try to make some measurements and report back by tonight.

Wachara C.

[WrineX]

the reason why i cant measure is just i can only measure up to 2M this is ofcoourse far more, if its conductive at all. for now i forget about the ink stuf. measures my new mix today with mic and its exactly the same output as yesterday .

[chinsettawong]

Hi,

I make two small samples to measure the conductivity (resistivity) of the black poster ink I used. They all show some conductivities as shown.





The first paint sample is thicker (darker) than the second and its resistivity corresponds to that. I get 220K ohm from the first and 4.8M ohm from the second.

The measurements are measured by a cheap multimeter.

I'm quite sure that black ink contains carbon.

Wachara C.

[WrineX]

verry nice, now thats cleared wich brand is it and what for ?

poster ink ?