carbon black!

[moray james]

The Cabot site has more information on Carbon Black than you will ever care to know.

[jelanier]

The site I linked earlier does have the conductive carbon black. I just received mine in the mail. I am going to make a test formulation this weekend.

The source is:

Lampblack - conductive (carbon black) - microfine - Stock #C154C - ORM
from Firefox Enterprises. Chemicals - I-L.


Jim

[Ulf Eliasson]

Try some antistatic polish instead of messing with carbon black
The antistatic vinyl polish I use cannot be easier to apply and probably among the thinnest coatings you can find too. So far I'm not disappointed!

[Ian Finch]

There is a commercial product used worldwide in the electronics industry as a conductive coating. It's called "Aquadag" and contains colloidal graphite as the conductor. It's marketed by Acheson in the US and there are others worldwide. Like most carbon/graphite products, it's been around longer than most of us. Just look at a few old CRTs. The distinction between carbon and graphite powders, solid engineering materials and electrical contacts is pretty vague as some are natural and others synthetic or mixed. Sy pointed out the broad difference.

The conductivity of any matrix like a glue, plastic, ceramic etc. containing the substance only increases appreciably after a threshhold is reached. This could be anywhere from 5% upwards before an exponential increase appears. In the plastics I once developed, it was 11-35%, at which point physical strength was reducing to impractical levels. This can also apply to the solid (dried) content of coatings.

There are a lot of carbon sources known also as lampblack, boneblack,vegetable black etc. which are dyestuffs for plastic, paint and inks. They are ultrafine and utterly filthy but yield stronger, less conductive materials than graphites. Carbons may be coated to aid dispersion but this ruins conductivity. The main user here though, is the tyre industry. Yep, carbon black - cheap and by the ton(ne).
BTW. Fine and ultrafine metal powders of nickel, alloy steels, copper etc. are also used to enhance conductivity. Whilst expensive, they are much less "black".
regards

[JonasKarud]

Originally Posted by Ulf Eliasson

No luck with ink so far
I have tested a couple of black inks with no luck so far. I couldn’t notice any improvement compared to only glue and H2O. First I tested leftovers in the cartridge from my HP ink jet printer and then bought a bottle of Parker’s Quink.

I also tested the black powder my wife uses when she mixes porcelain paint. No luck with this either.

Antistatic vinyl polish for cars interior works perfectly
It is a 250ml spray bottle bought for €4 at the Nordic car accessories shop Biltema (36-9301).

First I tested to polish the membrane with it as you would with the interior of your car and it worked fine, but I suppose it would vaporize after a shorter or longer time. But the advantage to polish it on is that you probably cannot find anything else that add less mass to the membrane so I will probably make some kind of long term test some time.

What I’m using now (since a week or so) is a mixture of:
1 part Antistatic vinyl polish
1 part water based glue
4 parts H2O

I have used two water based transparent glues, both equally successful:
Casco Hobby glue (2935)
Casco Universial glue (2914)
Casco is part of the Akzo Nobel Deco group if you cannot find Casco on your market.

Ulf, how high is the resistance when you use the Vinyl polish and Casco glue? I've tried both glues with the polish and destilled water and get a resistance higher than 1000 gigaohm and very little sound output. If I polish the membrane with vinyl polish I get a very high sound output, but as you say, for how long.....

[esl 63]

Jonas, when i aksed you approx nine years ago you had a "perfect" coating you said. Is it something you want to tell about or something you sell?

Martin P

[Ulf Eliasson]

After 4 month; I'm still fully satisfied!
So far I only see upsides:

• Easy to find and cheap
• Easy to apply; Just spray from the bottle and spread it evenly with a paper tissue
• Probably among the thinnest coatings you can find
• It is aesthetic appealing, because it is totally transparent

I’m using it on my full range panels:

• They are biased with 7kV
• The longtime stability is no problem for me, because they can easily be disassembled if I need to apply new coating in a year or so. But again; so far no tendencies in that direction
• Now during summer I guess the humidity surrounding the panels are the same as outdoors, i.e. 70-85%.

[WrineX]

Originally Posted by Ulf Eliasson

After 4 month; I'm still fully satisfied!
So far I only see upsides:

• Easy to find and cheap
• Easy to apply; Just spray from the bottle and spread it evenly with a paper tissue
• Probably among the thinnest coatings you can find
• It is aesthetic appealing, because it is totally transparent

I’m using it on my full range panels:

• They are biased with 7kV
• The longtime stability is no problem for me, because they can easily be disassembled if I need to apply new coating in a year or so. But again; so far no tendencies in that direction
• Now during summer I guess the humidity surrounding the panels are the same as outdoors, i.e. 70-85%.

yeah thats funny i use since 1 month Antistatic spray from contact Chemie. its a can wich i spray on some cloth and rub in over the foil. i measures between the 0,3 Giga ohm and 2 Giga, depends on hoiw much you use and how much you delute it with alcohol. they play as loud as they did almost 1 month ago. also funny is that a store in the netherlands that restores audiostatics or recoated them used the same stuff, and he never had any complains of persons that pay almost 150 euro's a panel. so i think it will stay on the film pretty well. i wonder how it hold when its winter and the moisture humanity is really low. but for now it worked like a charm. its clear clear clear you cant see anything at all. iwch can be di9ficult when aplying. but i just took loads of measurements. best way is to delute it allot and then aplying allot, wich evaporate to get even coating. maybe even delute it with something else wich set better on mylar, did not try it yet but who knows.

[JonasKarud]

Martin P, go to this thread, post 97 and onwards...

ESL Diaphragm coating

[esl 63]

I have different kinds of Degussa Carbon Black.
Some of them i do not use.
The thing is with carbon black solvents and even powder is that over time carbon black has a tendency to arrange itself in larger molecules. So you have to either grind it just before use or you have to buy it very fresh from the supplyer.
Depending on how sensitive your application is of course...

Martin P