In article ,
Kamus of Kadizhar wrote:

Maybe this isn't the right group, but I can't find the right one, so
appologies in advance if this is OT.

I'm trying to build some Leyden jars
http://chem.ch.huji.ac.il/~eugeniik/instruments/archaic/leyden_jars.htm .

A Leyden Jar is basically an insulating container (glass, plastic) with a
thin coating of a metal conductor on the inside and the outside.

Normally, you apply a metal foil both inside and outside the container.

But... I want to build these inside wine bottles, so I can't reach in and
apply a coating by hand.

I've thought about metallic paint - thinning it and swishing it around.
Something like this: http://www.lessemf.com/292.html . I've though
about electroplating, but that doesn't seem practical.

To prevent sparking, the coating needs to stop about 1/3 of the way from
the top of the jar.

Any suggestions for coating the inside of a container with a conductive
film, without actually reaching in? Oh, and this is being done on a
shoe-string budget, so expensive solutions are out....

TIA,

--Kamus

When my halogen bulbs burn out on my car they leave a clean shiny
metallic coating on the inside of the bulb. If you could find out what
process causes that you might be able to reproduce it to coat your jars.
Sorry i can't be more specific.

--
B.B. --I am not a goat! thegoat4 at airmail.net
Fire the stupid--Vote.

In article
,
"B.B." u wrote:

When my halogen bulbs burn out on my car they leave a clean shiny
metallic coating on the inside of the bulb. If you could find out what
process causes that you might be able to reproduce it to coat your jars.
Sorry i can't be more specific.

Bascially, what you're seeing in a burnt-out halogen bulb is the result
of an EXTREMELY crude and uncontrolled example of the coating method
called "sputtering". Halogen bulbs run *HOT*. Hot enough to literally
"boil off" atoms of the filament metal. The halogen gas the bulb is
filled with is supposed to (and at least to some extent, does) cause the
metal vapor to re-deposit on the filament, rather than the glass,
achieving two results: 1) Longer life (since the filament stays a
filament, rather than turning into a coating on the glass) and 2)
Brighter output, which is a direct result of the reduction of plating on
the glass to block the light. When they burn out "slowly", it's often
due to "micro-leaks" that let the halogen out, and "plain air" in, which
in turn allows the "plate onto the glass" process to start happening,
and continue until the filament is eroded so far that it's unable to
maintain physical integrity and breaks.

A "mechanical" burn out (A hard jolt, etc) won't show the plating,
because the atmosphere in the bulb has remained constant, but the motion
from the impact has broken the filament.

--
Don Bruder - - New Email policy in effect as of Feb. 21, 2004.
I respond to Email as quick as humanly possible. If you Email me and get no
response, see http://www.sonic.net/~dakidd/main/contact.html Short
form: I'm trashing EVERYTHING that doesn't contain a password in the subject.

"B.B." u wrote in message
news
When my halogen bulbs burn out on my car they leave a clean shiny
metallic coating on the inside of the bulb. If you could find out what
process causes that you might be able to reproduce it to coat your jars.
Sorry i can't be more specific.

Ah, interesting angle! Lerch what'shisname did that on a larger scale,
aluminizing his own telescope mirrors... what you do is suck a good vacuum
then boil some metal. The vapor condenses on the walls.

Masking and getting a layer thick enough for pulse discharge would be a
problem.

Tim

--
"I have misplaced my pants." - Homer Simpson | Electronics,
- - - - - - - - - - - - - - - - - - - - - - --+ Metalcasting
and Games: http://webpages.charter.net/dawill/tmoranwms

Kamus of Kadizhar wrote in message news:pan.2004.05.28.12.55.42.121711@NsOeSiPnAeMr. com...
Maybe this isn't the right group, but I can't find the right one, so
appologies in advance if this is OT.

I'm trying to build some Leyden jars
http://chem.ch.huji.ac.il/~eugeniik/instruments/archaic/leyden_jars.htm .

A Leyden Jar is basically an insulating container (glass, plastic) with a
thin coating of a metal conductor on the inside and the outside.

Normally, you apply a metal foil both inside and outside the container.

But... I want to build these inside wine bottles, so I can't reach in and
apply a coating by hand.

I've thought about metallic paint - thinning it and swishing it around.
Something like this: http://www.lessemf.com/292.html . I've though
about electroplating, but that doesn't seem practical.

To prevent sparking, the coating needs to stop about 1/3 of the way from
the top of the jar.

Any suggestions for coating the inside of a container with a conductive
film, without actually reaching in? Oh, and this is being done on a
shoe-string budget, so expensive solutions are out....

TIA,

--Kamus

Foil outside, shot inside. Lead shot runs about $12-15/25 lb bag, you
should have enough to do a number of bottles, depending on size, out
of one bag. BBs also spring to mind, not as heavy, copperplated,
probably not as cheap. A book on electrostatic generators I've got
has construction details for Leyden jars made with shot filler, they
used beaded chain for making contact with the top ball. You could
also use salt water for a filler but you'd want to make sure that all
your pieces were non-corrosive and cork the thing up well,
electrostatics and humidity don't get along. IIRC, one of my really
old "electrician's" books has details on making Leyden jars that way,
too, I think they floated mineral oil on top of the salt water. I
think they used dry cell carbon for making contact inside. #6 dry
cells are antiques these days, I don't know what you'd use to
substitute.

Stan

"Stan Schaefer" wrote in message
om...
#6 dry cells are antiques these days, I don't know what you'd use to
substitute.

Showing your age maybe? ;o) I don't think there's been a time since they
were widely sold that they haven't been available. Note "Heavy-duty"
batteries lack the "alkaline battery" note on them!

Tim

--
"I have misplaced my pants." - Homer Simpson | Electronics,
- - - - - - - - - - - - - - - - - - - - - - --+ Metalcasting
and Games: http://webpages.charter.net/dawill/tmoranwms

Colloidial Graphite in Isapropanol (SP?) is about the only US Navy
approved
thread lubricant in use today. Just don't get it on your fingers, it is
VERY difficult to wash off.

Shawn

Yup thats the stuff. This came from that motherboard manufactureing
plant that Im helping to clear out.


It's probably just lubricant for high precision machinery. But it would make
a great non-stick coating for foundry work. You could paint it onto clay
crucibles, steel with a very mild rust, tools, etc. Would probably make the
worlds best kiln wash. Boron Nitride also works good for that stuff and it's
more inert but graphite would work very well.