Conductive coatings
Bob
Nickel coating spray is too dear in the quantities I need.
I have mixed graphite with a water based glue but I think that
the glue partially insulates the particles. I only need a resistance
of around 1k ohms over about 12 inches and it would seem that
something better than this glue should be available.
My kid had some imitation chrome paint years ago and I remember
measuring the paint stain on the label and it was highly conductive
but can't remember the brand and have been told that ordinary
consumer paints are delibritary made non-conductive now for
rather obvious reasons.
Any ideas?
Asimov
--- on the topic of "Conductive coatings"
Someone here once posted a recipe for fixing the carbon tracks on worn
potentiometers using mixes of copier toner and graphite powder:
Nigel Cook <div...@tcp.co.uk> wrote:
> This tip applies to low voltage, low power carbon potentiometers where
> for physical constraints it is not possible to replace.
>
> Dismantle the pot down to the carbon track clean/degrease.
> Make up resistive compound from photocopier toner and graphite powder
> obtainable from locksmiths for dry "lubrication".
>
> The following resistivity values are very approximate for .02 inch thick
> film graphite:toner ratios;
>
> 1:1 , 200 ohm per square inch
> 1:10 , 100k ohm per square inch
> 1:30 , 10M ohm per square inch
>
> Mask off area surrounding carbon track,sprinkle on the powder, fuse the
> film in a low oven approx 150 degrees centigrade or place on a thin
> sheet over a hot air paint stripper on low setting. When fused lightly
> abraid with a nail file, and reassemble pot. High ohmic pots are a bit
> iffy, low ohmic are fine.
Bo> From: "Bob" <ret...@idx.com.au>
Bo> I would like to be able to make a conductive paint if possible.
Bo> Nickel coating spray is too dear in the quantities I need.
Bo> I have mixed graphite with a water based glue but I think that
Bo> the glue partially insulates the particles. I only need a resistance
Bo> of around 1k ohms over about 12 inches and it would seem that
Bo> something better than this glue should be available.
Bo> My kid had some imitation chrome paint years ago and I remember
Bo> measuring the paint stain on the label and it was highly conductive
Bo> but can't remember the brand and have been told that ordinary
Bo> consumer paints are delibritary made non-conductive now for
Bo> rather obvious reasons.
Bo> Any ideas?
Neill Wilson
Asimov
--- on the topic of "Re: Conductive coatings"
Sure, stuff like aluminum paint and metalic leaf finish in gold will be
conductive.
NW> From: Neill Wilson <neilw...@cogeco.ca>
NW> how about aluminum colored paint. it should be a good conductive
NW> coating
Bob
high resistance even with less toner and I wouldn't be able to
apply heat in this case.
Normal gold and aluminum paint isn't conductive.
I have a tin of aluminum powder here and it doesn't conduct at all.
Maybe the particles have surface corrosion? It certainly looks
shiny.
I could use tape for this but it would have to have a noticably higher
resistance than lead tape.
Thanks for the ideas, every bit helps.
Bob.
"Asimov" <warpcastgate@-removethis-bbs.juxtaposition.dynip.com> wrote in
message news:MSGID_1=3a167=2f133.0_...@fidonet.org...
Asimov
--- on the topic of "Re: Conductive coatings"
You're welcome. Not to extoll trademarks blatantly but Sheffield metal
leaf finish *is* conductive. I don't know if it's available where you
are though. Some metalic type Testors model paints are conductive too.
Bo> From: "Bob" <ret...@idx.com.au>
Bo> I like the post re using toner but unfortunately this would result in
Bo> a high resistance even with less toner and I wouldn't be able to
Bo> apply heat in this case.
Bo> Normal gold and aluminum paint isn't conductive.
Bo> I have a tin of aluminum powder here and it doesn't conduct at all.
Bo> Maybe the particles have surface corrosion? It certainly looks
Bo> shiny.
Bo> I could use tape for this but it would have to have a noticably higher
Bo> resistance than lead tape.
Bo> Thanks for the ideas, every bit helps.
Bo> Bob.
Bo> "Asimov" <warpcastgate@-removethis-bbs.juxtaposition.dynip.com> wrote
Bo> in message news:MSGID_1=3a167=2f133.0_...@fidonet.org...
> "Neill Wilson" wrote to "All" (24 Jan 03 22:59:44)
> --- on the topic of "Re: Conductive coatings"
>
> Sure, stuff like aluminum paint and metalic leaf finish in gold will be
> conductive.
>
> NW> From: Neill Wilson <neilw...@cogeco.ca>
>
> NW> how about aluminum colored paint. it should be a good conductive
> NW> coating
> NW> Asimov wrote:
> > "Bob" wrote to "All" (24 Jan 03 13:22:45)
> > --- on the topic of "Conductive coatings"
> >
> > Someone here once posted a recipe for fixing the carbon tracks on worn
> > potentiometers using mixes of copier toner and graphite powder:
> >
> >
> > Nigel Cook <div...@tcp.co.uk> wrote:
> >
> >>This tip applies to low voltage, low power carbon potentiometers where
> >>for physical constraints it is not possible to replace.
> >>
> >>Dismantle the pot down to the carbon track clean/degrease.
> >>Make up resistive compound from photocopier toner and graphite powder
> >>obtainable from locksmiths for dry "lubrication".
> >>
> >>The following resistivity values are very approximate for .02 inch
Bo> thick
do_not_spam_me
> how about aluminum colored paint. it should be a good conductive coating
It barely conducts, even when sanded to remove oxidation, and I mean a
megaohm per square inch. Cold galvanizing spray, which is > 95% zinc,
is an even better insulator. The only metal paints that conduct
decently contain either nickel (M.G. Chemicals, about $20 an 11 oz
spray can) or silver.
Dave M
coating onto, and how large an area you need to coat. That might be a help
to someone who can come up with a better idea.
I have a few suggestions, none of which I can verify as being actually
workable for you.
1) A plating solution, such as electroless tin plating
2) Copper powder can be found in craft stores (such as Michael's) or in the
crafts dept of Walmart. Yes, this stuff is very conductive.
3) Powdered copper, such as that found in automobile radiator leak stop
solutions
Dave M
"Bob" <ret...@idx.com.au> wrote in message news:3e30a2de@news1...
Bob
I have been making these for years for personal use only and have used all
popular ideas. The shield is very critical in that it doesn't introduce
extra
capacitance to the coil. Old VLF designs weren't critical in this area.
I can obtain conductive powders but would like a few tips on the means of
making a paint as most liquids tend to fully or partially insulate the
particles.
Some liquids are very conductive when wet but are not when dry.
Lead tape is less conductive than some materials but the resistance is still
too low for what I want otherwise a tape might suffice.
Bob.
"Dave M" <dgma...@atxxt.net> wrote in message
news:SkUY9.15093$zF6.1...@bgtnsc04-news.ops.worldnet.att.net...