Quad ESl63 coating

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Ok for god sake. another coating question.

But for all people still looking for the right conductive carbon black ink.

Tatoo ink! the filler type called number 12 is loaded. when used without delution i get 200k Ohm or something. but deluting is till hard to maintain conductivity.


I then ordered 2 bags of carbon black from a pigment manufacture for paints. 200 grams for 20 euro. thats enough to last a lifetime.

But of course its not THAT easy. getting the carbon to disperse or suspend in a medium is not easy at all.


choice of binder is hard to. i use some acrylic paint from local hardware store. but not all acrylics work(tried 5 most stopped conductivity complete). spraying the coating is even harder then brushing on with a foam brush.


with a foam brush in 2 layers i manage to get 3-15 Mega ohm with an airbrush i get nothing or 1mega ohm or waaaaaaay lower.

i have like 20 cups standing in my shed with all different mixes...... maybe quad used some graphite as well. since my coating looks more black then there's. could also be they used clear acrylic, or used only acrylic medium whitch is white colourish. i used black arylic.


does anyone have some tips to make the paint more sprayable? i tried acrylic alcohol. acrylic water and tension breaker. and acrylic water alcohol. but they all kinda suck. mylar is hard to spray on without getting droplets. it either has to dry instant or form a wetting film before drying without pulling the carbon back to the wettest spot on the film.
 
Ok i made some improvements. but its nasty... (the smell, i do need a breathing mask soon)

I now used Polyurethane/acetone/and carbon black.

i could get ranges from 12 K Ohm to 110 M ohm. but there is a fine balance between conductive to unreadable on my crappy meter. also acetone dries fast.. very very fast. anyone know of something to calm it down a notch ? so it can wet a bit better ?

now the acetone and urethane dries instantly when it hits the Mylar, that's nice, but it looks like some of the carbon is ending up outside the binder of the urethane. witch leaves a very brittle(more like coating with carbon on top) coating. when you move your finger over it you can assure its black :) or brownish.

when applied with a brush , the coating is more tacky, and becomes more solid by the (30) minutes. it takes time to completely dry out(bottle says 24 hours). but not or not much of carbon black is released when rubbed.


1.5 part urethane 16 parts of acetone and (very scientific) 1 Thea spoon carbon black(need a more precise scale) applied with a brush in 2 cm wide stroke, ends up with a 110 M ohm coating.

The urethane used it 1 component witch has low viscosity, and is thinned down as it is so it seems. it is used for making concrete watertight in basements.
 
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Guys,
the problem with carbon is the particles' shape. It should be either flake or fiber like. Otherwise it would not be in contact with each other.
In regard to charge ring: use carbon paint in cans Graphite 33 or the like. Masking tape and you get highly conductive flexible trace. The bad: nothing sticks to graphite paint.
Again try to activate film surface if possible.
 
First there is a lot supplyers of diluted carbon black one is DEGUSSA.
DEGUSSA as an example, have a variety of dilutions both water based and alcohole based.
Regarding handeling of all types of carbon black, is that you have to grind it very fine, and if you store a can long enough, weeks or month you have to grind it again!
So to be on the safe side, have a good chat with the supplyer and order fresh stuff. Dont bother if it is so thin at some places after you applied it that its nearly transparant, really fine grinded carbon is transparant and still dissipative!
I have done lots of experiments together with MTAUDIO when we had a workshop together (repairing 63s), and we believe that the original QUAD coating is still one of the best there is... but even though, i believe that QUAD could do some improvements by taking advice from chemical experts.
 
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quad uses either graphite or carbon. and i must say there coating is pretty low resistance still around 6 Meg to 20 M, but then again who cares they work.


DEGUSSA now called Evonik, the product catalog says they don't handle carbon black as a product anymore.... also the plant in the Netherlands is gone.
 
Ok i tried some different things. i got a cheap mixer/blender(the handheld ones) to try and do some high shear mixing. and i bought some acrylic medium without any pigments. i would love the coating to be all water based. for my health and the earth :) marketing crap.... but really the fumes from some thinners really scream dont breath me in or drop me.

The mixer be it a shitty one (since i dont want to ruin my good blender) does not get to 10000 rpm my guess :) so maybe later on i extract the shaft with the blades. most mixers use a 6 mm shaft which fit in my collet of my old spindle motor for the cnc, witch can go from 8000 to 22000 rpm. more then enough, and 800watt is also more then enough for a small batch. another benefit is that the motor fits the clamp of a a drill press. so i can mix the stuff for half an hour without any problems. i think my cheap blender will fry when i want to run it for 30 min :)

i think i might be able to disperse the carbon pretty good in the end for not much money at all. i just used the mixer for like 5 or 10 minutes. so i think the new motor and longer mixer would improve things even more.
 
Old post yes same issue today

Did anyone ever find a workable consistent coating in the end ?
Simple Licron Crystal ?
I do have professional spray equipment and know how to spray if needed.
The nylon coating of the 57,s doesn,t work on the further spacing distance of the 63/988 panels from research and looking at my own examples of each panel construction. Very high resistance 57,s and lower megohm range on the 63/988

I now ask because I am in the process of refurbishing a set of 988,s that use the same panel construction as the 63,s
The usual perimeter pulling away of the pcb material Behind the Mylar constitutes a new membrane to be made
I could reglue, but on some of them, it has pulled away towards the center area
And really want to remake all of them rather than one or two only to have issues develop on the others later down the road..,
It looked like the grids along with the nylon mess were hot glued in one shot at the factory.

These particular stock panels peak resonance is 74 hz and have already made a new panel jig (perimeter air tube style ) to get same close specs before coating.

So in 2017 , what coating now consistently works on these style panels ?

Appreciate any comments from those that have BTDT on the 63/988 panels

Regards
David
 
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