Anyone had experience using metalization on glass (mirror)
as a ground plane or shield?
Any data on conductivity etc?
Anyone had experience using metalization on glass (mirror)
as a ground plane or shield?
Any data on conductivity etc?
Anyone had experience using metalization on glass (mirror)
as a ground plane or shield?
Any data on conductivity etc?
RL
On 28/11/2024 12:53 am, legg wrote:
Anyone had experience using metalization on glass (mirror)
as a ground plane or shield?
None.
Any data on conductivity etc?
It's difficult to get much below 100ohm per square with metal layers.
You can't get thinner than one atom thick, and while in theory the >microcrystals of metal can offer a circuitious path, you are laying them
down at random.
I made the mistake of asking for vacuum deposited layer of carbon with >highish resistance, and got told off by the people who did it.
We ended up using a thick film layer of some very resistive metal
oxide-based thick-film ink - about a micron of it.
legg <legg@nospam.magma.ca> wrote:
Anyone had experience using metalization on glass (mirror)
as a ground plane or shield?
Any data on conductivity etc?
RL
The best quality second-surface mirrors are coated with silver, followed by >copper plating and a coat of paint. Those should be pretty good if you can >get wires on them.
Poorer ones have aluminum coatings around 2-3 nm thick and no plating.
Cheers
Phil Hobbs
legg <legg@nospam.magma.ca> wrote:
Anyone had experience using metalization on glass (mirror)
as a ground plane or shield?
Any data on conductivity etc?
RL
The best quality second-surface mirrors are coated with silver, followed by >copper plating and a coat of paint. Those should be pretty good if you can >get wires on them.
Poorer ones have aluminum coatings around 2-3 nm thick and no plating.
On Wed, 27 Nov 2024 14:24:20 -0000 (UTC), Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net> wrote:
legg <legg@nospam.magma.ca> wrote:
Anyone had experience using metalization on glass (mirror)
as a ground plane or shield?
Any data on conductivity etc?
RL
The best quality second-surface mirrors are coated with silver, followed by >> copper plating and a coat of paint. Those should be pretty good if you can >> get wires on them.
Poorer ones have aluminum coatings around 2-3 nm thick and no plating.
Cheers
Phil Hobbs
I think pressure contact will be good enough, so long as its renewed regularly, maybe with a conductive grit.
Will have to treat the isolated glass surface with something to
reduce static, or stuff will start flying away at inconvenient
times.
RL
On Wed, 27 Nov 2024 14:24:20 -0000 (UTC), Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net> wrote:
legg <legg@nospam.magma.ca> wrote:
The best quality second-surface mirrors are coated with silver, followed
Anyone had experience using metalization on glass (mirror)
as a ground plane or shield?
Any data on conductivity etc?
RL
by copper plating and a coat of paint. Those should be pretty good if
you can get wires on them.
Poorer ones have aluminum coatings around 2-3 nm thick and no plating.
Cheers
Phil Hobbs
I think pressure contact will be good enough, so long as its renewed regularly, maybe with a conductive grit.
On 27/11/2024 16:41, Joe Gwinn wrote:
On Wed, 27 Nov 2024 14:24:20 -0000 (UTC), Phil HobbsAt high enough frequencies there is no need for direct connection.
<pcdhSpamMeSenseless@electrooptical.net> wrote:
legg <legg@nospam.magma.ca> wrote:
Anyone had experience using metalization on glass (mirror)
as a ground plane or shield?
Any data on conductivity etc?
RL
The best quality second-surface mirrors are coated with silver, followed by >>> copper plating and a coat of paint. Those should be pretty good if you can >>> get wires on them.
A classic way to connect to such things is conductive silver epoxy,
probably to silver-plated copper wire. Not tin-plated for long-term
use.
.<https://www.masterbond.com/properties/silver-filled-electrically-conductive-adhesives>
As for shielding effectiveness, the key question is the resistance of
a square of the coating, connected only on opposite parallel sides.
Poorer ones have aluminum coatings around 2-3 nm thick and no plating.
Probably won't work, between high square resistance and oxide layer
preventing reliable connection.
Though people do use metallized Mylar film, with a long bare tinned
copper ground wire in direct contact with the aluminum side, and in a
cable this does work.
Joe Gwinn
Adhesive copper tape stuck to the varnish film on the back of an
ordinary mirror may provide enough capacitive coupling to make a
good connection. It all depends on the proposed application, which
we don't know.
John
Anyone had experience using metalization on glass (mirror)
as a ground plane or shield?
Any data on conductivity etc?
RL
On Wed, 27 Nov 2024 08:53:41 -0500, legg <legg@nospam.magma.ca> wrote:
Anyone had experience using metalization on glass (mirror)
as a ground plane or shield?
Any data on conductivity etc?
RL
Why use glass? Why not copperclad FR4?
On 27/11/2024 16:41, Joe Gwinn wrote:
On Wed, 27 Nov 2024 14:24:20 -0000 (UTC), Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net> wrote:
legg <legg@nospam.magma.ca> wrote:
Anyone had experience using metalization on glass (mirror)
as a ground plane or shield?
Any data on conductivity etc?
RL
The best quality second-surface mirrors are coated with silver, followed by
copper plating and a coat of paint. Those should be pretty good if you can
get wires on them.
A classic way to connect to such things is conductive silver epoxy, probably to silver-plated copper wire. Not tin-plated for long-term
use.
.<https://www.masterbond.com/properties/silver-filled-electrically-condu ctive-adhesives>
As for shielding effectiveness, the key question is the resistance of
a square of the coating, connected only on opposite parallel sides.
Poorer ones have aluminum coatings around 2-3 nm thick and no plating.
Probably won't work, between high square resistance and oxide layer preventing reliable connection.
Though people do use metallized Mylar film, with a long bare tinned
copper ground wire in direct contact with the aluminum side, and in a
cable this does work.
Joe GwinnAt high enough frequencies there is no need for direct connection.
Adhesive copper tape stuck to the varnish film on the back of an
ordinary mirror may provide enough capacitive coupling to make a
good connection.
On Wed, 27 Nov 2024 12:53:01 -0800, john larkin <jl@glen--canyon.com>
wrote:
On Wed, 27 Nov 2024 08:53:41 -0500, legg <legg@nospam.magma.ca> wrote:
Anyone had experience using metalization on glass (mirror)
as a ground plane or shield?
Any data on conductivity etc?
RL
Why use glass? Why not copperclad FR4?
Rugged repeated use - subjected to fire and impact.
Will be possibly burning FR4 in contact with it.
A work surface.
RL
John R Walliker <jrwalliker@gmail.com> wrote:
On 27/11/2024 16:41, Joe Gwinn wrote:
On Wed, 27 Nov 2024 14:24:20 -0000 (UTC), Phil HobbsAt high enough frequencies there is no need for direct connection.
<pcdhSpamMeSenseless@electrooptical.net> wrote:
legg <legg@nospam.magma.ca> wrote:
Anyone had experience using metalization on glass (mirror)
as a ground plane or shield?
Any data on conductivity etc?
RL
The best quality second-surface mirrors are coated with silver, followed by
copper plating and a coat of paint. Those should be pretty good if you can
get wires on them.
A classic way to connect to such things is conductive silver epoxy,
probably to silver-plated copper wire. Not tin-plated for long-term
use.
.<https://www.masterbond.com/properties/silver-filled-electrically-condu >> > ctive-adhesives>
As for shielding effectiveness, the key question is the resistance of
a square of the coating, connected only on opposite parallel sides.
Poorer ones have aluminum coatings around 2-3 nm thick and no plating.
Probably won't work, between high square resistance and oxide layer
preventing reliable connection.
Though people do use metallized Mylar film, with a long bare tinned
copper ground wire in direct contact with the aluminum side, and in a
cable this does work.
Joe Gwinn
Adhesive copper tape stuck to the varnish film on the back of an
ordinary mirror may provide enough capacitive coupling to make a
good connection.
This can even work at highish audio frequencies:
I was trying to trace some disconnected house wiring by feeding about
50v of 1 Kc/s audio into the accessible end and following the signal >capacitively with a high impedance probe connected to a tuned amplifier
and headphones. The wires were in the space between the ceiling of the >downstairs rooms and the floorboards of the upstairs rooms; it was
easiest to trace them from below because there was a lot of furniture
and other clutter in the upstairs rooms.
The signal led towards an outer wall of the house which had had a garage >built onto it. From inside the house, the wires appeared to be running
along the wall in the garage , but there were no wires visible in the
garage ... and from the garage, the signal appeared to be coming from
inside the house.
Then I realised that there was a large mirror inside the house on that
wall and the signal was being capacitively coupled to the top edge of
the mirror by wires that must have been at least a foot above it and >separated by a plasterboard [drywall] ceiling. The whole mirror was >re-radiating the signal.
On Thu, 28 Nov 2024 11:15:01 +0000, liz@poppyrecords.invalid.invalid
(Liz Tuddenham) wrote:
John R Walliker <jrwalliker@gmail.com> wrote:
On 27/11/2024 16:41, Joe Gwinn wrote:
On Wed, 27 Nov 2024 14:24:20 -0000 (UTC), Phil Hobbsfollowed by >> copper plating and a coat of paint. Those should be
<pcdhSpamMeSenseless@electrooptical.net> wrote:
legg <legg@nospam.magma.ca> wrote:
Anyone had experience using metalization on glass (mirror)
as a ground plane or shield?
Any data on conductivity etc?
RL
The best quality second-surface mirrors are coated with silver,
pretty good if you can >> get wires on them. > > A classic way to
connect to such things is conductive silver epoxy, > probably to
silver-plated copper wire. Not tin-plated for long-term > use. > >
.<https://www.masterbond.com/properties/silver-filled-electrically-cond
u > ctive-adhesives> > > As for shielding effectiveness, the key
question is the resistance of > a square of the coating, connected only
on opposite parallel sides. > > >> Poorer ones have aluminum coatings
around 2-3 nm thick and no plating. > > Probably won't work, between
high square resistance and oxide layer > preventing reliable
connection. > > Though people do use metallized Mylar film, with a long
bare tinned > copper ground wire in direct contact with the aluminum
side, and in a > cable this does work. > > Joe Gwinn At high enough
frequencies there is no need for direct connection. Adhesive copper
tape stuck to the varnish film on the back of an ordinary mirror may
provide enough capacitive coupling to make a good connection.
This can even work at highish audio frequencies:
I was trying to trace some disconnected house wiring by feeding about
50v of 1 Kc/s audio into the accessible end and following the signal >capacitively with a high impedance probe connected to a tuned amplifier
and headphones. The wires were in the space between the ceiling of the >downstairs rooms and the floorboards of the upstairs rooms; it was
easiest to trace them from below because there was a lot of furniture
and other clutter in the upstairs rooms.
The signal led towards an outer wall of the house which had had a garage >built onto it. From inside the house, the wires appeared to be running >along the wall in the garage , but there were no wires visible in the >garage ... and from the garage, the signal appeared to be coming from >inside the house.
Then I realised that there was a large mirror inside the house on that
wall and the signal was being capacitively coupled to the top edge of
the mirror by wires that must have been at least a foot above it and >separated by a plasterboard [drywall] ceiling. The whole mirror was >re-radiating the signal.
It's interesting to walk around and listen to ambient e and h fields,
and light too.
You can trace wires by listening to the 50/60 Hz fields, usually with
lots of harmonics.
john larkin <JL@gct.com> wrote:
On Thu, 28 Nov 2024 11:15:01 +0000, liz@poppyrecords.invalid.invalid
(Liz Tuddenham) wrote:
John R Walliker <jrwalliker@gmail.com> wrote:
On 27/11/2024 16:41, Joe Gwinn wrote:
On Wed, 27 Nov 2024 14:24:20 -0000 (UTC), Phil Hobbsfollowed by >> copper plating and a coat of paint. Those should be
<pcdhSpamMeSenseless@electrooptical.net> wrote:
legg <legg@nospam.magma.ca> wrote:
Anyone had experience using metalization on glass (mirror)
as a ground plane or shield?
Any data on conductivity etc?
RL
The best quality second-surface mirrors are coated with silver,
pretty good if you can >> get wires on them. > > A classic way to
connect to such things is conductive silver epoxy, > probably to
silver-plated copper wire. Not tin-plated for long-term > use. > >
.<https://www.masterbond.com/properties/silver-filled-electrically-cond >> >> u > ctive-adhesives> > > As for shielding effectiveness, the key
question is the resistance of > a square of the coating, connected only >> >> on opposite parallel sides. > > >> Poorer ones have aluminum coatings
around 2-3 nm thick and no plating. > > Probably won't work, between
high square resistance and oxide layer > preventing reliable
connection. > > Though people do use metallized Mylar film, with a long >> >> bare tinned > copper ground wire in direct contact with the aluminum
side, and in a > cable this does work. > > Joe Gwinn At high enough
frequencies there is no need for direct connection. Adhesive copper
tape stuck to the varnish film on the back of an ordinary mirror may
provide enough capacitive coupling to make a good connection.
This can even work at highish audio frequencies:
I was trying to trace some disconnected house wiring by feeding about
50v of 1 Kc/s audio into the accessible end and following the signal
capacitively with a high impedance probe connected to a tuned amplifier
and headphones. The wires were in the space between the ceiling of the
downstairs rooms and the floorboards of the upstairs rooms; it was
easiest to trace them from below because there was a lot of furniture
and other clutter in the upstairs rooms.
The signal led towards an outer wall of the house which had had a garage
built onto it. From inside the house, the wires appeared to be running
along the wall in the garage , but there were no wires visible in the
garage ... and from the garage, the signal appeared to be coming from
inside the house.
Then I realised that there was a large mirror inside the house on that
wall and the signal was being capacitively coupled to the top edge of
the mirror by wires that must have been at least a foot above it and
separated by a plasterboard [drywall] ceiling. The whole mirror was
re-radiating the signal.
It's interesting to walk around and listen to ambient e and h fields,
and light too.
I once built an IR detector into the body of a little hand torch so that
I could carry it unobtrusively around the site where I worked. The >management hadn't told us they were installing surveillance equipment,
but the IR illuminators for the hidden cameras showed up quite clearly.
On Wed, 27 Nov 2024 22:08:13 -0500, legg <legg@nospam.magma.ca> wrote:
On Wed, 27 Nov 2024 12:53:01 -0800, john larkin <jl@glen--canyon.com>
wrote:
On Wed, 27 Nov 2024 08:53:41 -0500, legg <legg@nospam.magma.ca> wrote:
Anyone had experience using metalization on glass (mirror)
as a ground plane or shield?
Any data on conductivity etc?
RL
Why use glass? Why not copperclad FR4?
Rugged repeated use - subjected to fire and impact.
Will be possibly burning FR4 in contact with it.
A work surface.
RL
Stainless steel is pretty conductive.
On Wed, 27 Nov 2024 22:08:13 -0500, legg <legg@nospam.magma.ca> wrote:
On Wed, 27 Nov 2024 12:53:01 -0800, john larkin <jl@glen--canyon.com> >>wrote:
On Wed, 27 Nov 2024 08:53:41 -0500, legg <legg@nospam.magma.ca> wrote:
Anyone had experience using metalization on glass (mirror)
as a ground plane or shield?
Any data on conductivity etc?
RL
Why use glass? Why not copperclad FR4?
Rugged repeated use - subjected to fire and impact.
Will be possibly burning FR4 in contact with it.
A work surface.
RL
Stainless steel is pretty conductive.
On Thu, 28 Nov 2024 07:16:55 -0800, john larkin <JL@gct.com> wrote:
On Wed, 27 Nov 2024 22:08:13 -0500, legg <legg@nospam.magma.ca> wrote:
On Wed, 27 Nov 2024 12:53:01 -0800, john larkin <jl@glen--canyon.com> >>>wrote:
On Wed, 27 Nov 2024 08:53:41 -0500, legg <legg@nospam.magma.ca> wrote:
Anyone had experience using metalization on glass (mirror)
as a ground plane or shield?
Any data on conductivity etc?
RL
Why use glass? Why not copperclad FR4?
Rugged repeated use - subjected to fire and impact.
Will be possibly burning FR4 in contact with it.
A work surface.
RL
Stainless steel is pretty conductive.
which glass ain't . . .
Mind you, they're both just peachy to bend, drill, or to
work with simple hand tools - luckily avoided here once
sharp edges are tamed.
The consideration only came up when the basic material
showed up, free, begging for safe 'disposal'.
Not sure if the idea might be useful to others, elsewhere.
RL
On Fri, 29 Nov 2024 08:46:25 -0500, legg <legg@nospam.magma.ca> wrote:
On Thu, 28 Nov 2024 07:16:55 -0800, john larkin <JL@gct.com> wrote:
On Wed, 27 Nov 2024 22:08:13 -0500, legg <legg@nospam.magma.ca> wrote:
On Wed, 27 Nov 2024 12:53:01 -0800, john larkin <jl@glen--canyon.com> >>>>wrote:
On Wed, 27 Nov 2024 08:53:41 -0500, legg <legg@nospam.magma.ca> wrote: >>>>>
Anyone had experience using metalization on glass (mirror)
as a ground plane or shield?
Any data on conductivity etc?
RL
Why use glass? Why not copperclad FR4?
Rugged repeated use - subjected to fire and impact.
Will be possibly burning FR4 in contact with it.
A work surface.
RL
Stainless steel is pretty conductive.
which glass ain't . . .
Mind you, they're both just peachy to bend, drill, or to
work with simple hand tools - luckily avoided here once
sharp edges are tamed.
The consideration only came up when the basic material
showed up, free, begging for safe 'disposal'.
Mirrors? We went on a garden tour and one guy had a tiny yard with
mirrors on the fences. It looked huge, great fun. He served tea and
cookies to the visitors.
I'm not interested in plants like Mo is, but the garden tours are fun.
One guy near the Presidio has a waterfall in his back yard, Lobos
Creek.
Not sure if the idea might be useful to others, elsewhere.
RL
I recall some sort of conductive glass, antistat level, but you
probably don't have that.
There are antistat sprays, which I think are mildly hygroscopic, for
floors and such.
On Fri, 29 Nov 2024 07:59:08 -0800, john larkin <JL@gct.com> wrote:
On Fri, 29 Nov 2024 08:46:25 -0500, legg <legg@nospam.magma.ca> wrote:
On Thu, 28 Nov 2024 07:16:55 -0800, john larkin <JL@gct.com> wrote:
On Wed, 27 Nov 2024 22:08:13 -0500, legg <legg@nospam.magma.ca> wrote:
On Wed, 27 Nov 2024 12:53:01 -0800, john larkin <jl@glen--canyon.com> >>>>>wrote:
On Wed, 27 Nov 2024 08:53:41 -0500, legg <legg@nospam.magma.ca> wrote: >>>>>>
Anyone had experience using metalization on glass (mirror)
as a ground plane or shield?
Any data on conductivity etc?
RL
Why use glass? Why not copperclad FR4?
Rugged repeated use - subjected to fire and impact.
Will be possibly burning FR4 in contact with it.
A work surface.
RL
Stainless steel is pretty conductive.
which glass ain't . . .
Mind you, they're both just peachy to bend, drill, or to
work with simple hand tools - luckily avoided here once
sharp edges are tamed.
The consideration only came up when the basic material
showed up, free, begging for safe 'disposal'.
Mirrors? We went on a garden tour and one guy had a tiny yard with
mirrors on the fences. It looked huge, great fun. He served tea and
cookies to the visitors.
I'm not interested in plants like Mo is, but the garden tours are fun.
One guy near the Presidio has a waterfall in his back yard, Lobos
Creek.
A micro-hydro project?
Not sure if the idea might be useful to others, elsewhere.
RL
I recall some sort of conductive glass, antistat level, but you
probably don't have that.
There are antistat sprays, which I think are mildly hygroscopic, for
floors and such.
Well, I mentioned earlier that dish soap can get films in the
megohm/square region.
Encourages hygene, too.
RL
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