Originally posted by porkluvr
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I've made experiements with graphite paints. There are very good products (e.g. Kontact etc) that are in spray cans sold for few. I've used many times.
Good for VLFs coils... used in small homemade pinpointer too.
But I have also graphite powder of good quality. Lub. graphite used for machineries and tryed to made some mix of glues and paints with it.
I've tested a lot but results were not good cause too much graphite is required to make a good paint...
also colloidal solutions require some tannic acid to break granes into small particles... I know how-to but is too complex getting good quantity of tannic acid.
At the end I gave up on mixing stuff. But the recipe you signaled seems interesting... toluol paint, liquid tape... may work.
What I've found is that when you use also fine grains of graphite in your mix problem is that you need big layers of paint to get low resistance (low enough to be useful e.g. in VLF or PI) cause not-colloidal dispersions are hi-inefficient transporting electrons that need to jump from one layer to other of graphite "planes".
Problem is at interfaces between small particles.
I've painted a piece of plastic, dry it, then measured resistance (was around 10000ohm) then passed over (brushing) a piece of paper ... then measuring again resistance was around 500ohm : "aligment" of particles and smooth surface makes it become much more conductive.
When you use colloidal graphite paints you haven't such problems and get thin and hi-conductive layer cause varnish is uniform dispersion of colloidal particles: this is the real trick. But you need tannic acid to do it!

Best regards,
Max
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