Lyeden Jars

Dunno about dielectric absorption - I'd put it down to "less than complete discharge".

My pappy learned about how CRT's can sneak up on you - The hard way! He, the electrically-illiterate member of the family, was ripping the guts out of an early 1970's vintage 25 inch console TV so he could salvage some of the rather pretty wood that made up the top and sides for a project he was working on. This TV hadn't been plugged in, let alone turned on (it didn't even have a power cord attached to it - that had been gone for as long as the thing had been sitting in the garage) in at least 5 years that we knew of for sure, and perhaps longer. When he yanked the anode lead so he could pull the main chassis out of the box, things got impressive, quick. Ever see a 6'2", 270+ pound man fly without wings? I did... And he wasn't happy when he hit the wall and sorta slid down it like something out of a Warner Brothers cartoon. The "lightning bolt" that I saw jump from the anode connection on the tube to his wrist looked like it was as thick as my thumb, and made a "CRACK!" that could've easily been mistaken for a .22 rifle being fired. He ended up with a small burn on his wrist where it had bit him, and one helluva headache from smacking his gourd against the wall when he landed.

Could you fill the bottle with brass wool, swarf, or some other low density metal and get pretty much the same effect as if it were full of a conductive liquid but with less weight, no spilling and no evaporation?

The guy who suggested foil and a balloon...amazing! Wait...are those Mylar balloons conductive?

Vaughn

Hey Kamus,

Try using just plain old aluminum foil. Do a strip on the outside first. Then insert the largest strip you can feed into the neck, with a braided copper wire glued/fastened/soldered on it and then "power up". Each time you do, the piece inside will PLASTER itself in place. WHAM!! Just keep adding strips outside and in until you've covered the whole thing, then apply some sort of sticky to keep it in place. A "plain" condom or a kids toy balloon that is long and skinny can be inserted and then blown up and sealed off to hold the pieces in place, but I doubt you will need it. Or fill it with melted wax. Just seeing it happen is a good "Wow!!" for students. I've done it with

50KV neon sign transformers, and had no "arc-over", but be careful!!

Take care.

Brian Laws>Maybe this isn't the right group, but I can't find the right one, so

(Snip)

Good point, Jim. I assumed that after application and fusing, the carbon particles would come into contact and form a conductive coating.

Just now I probed an inkjet-printed black line on dry paper with my ohmmeter. It showed about 3 Mohms/cm. I also probed a similar line printed by a LaserJet 6MP. It reads about the same.

*Now* I assume that one could achieve a lower coating resistance by increasing the coating thickness in all three dimensions.

It's a possibility anyway.

--Winston

Which reminds me..I scored some 4 or 5 small bottles of Colloidial Graphite last week. They were packed in vermiculite then inside plastic bags.

Whats this stuff used for and why the vermiculite?

Gunner

That rifle hanging on the wall of the working-class flat or labourer's cottage is the symbol of democracy. It is our job to see that it stays there. - George Orwell

>

Can you imagine the mess if it breaks open in shipping? I guess the packaging can absorb some of it.

That's funny , I was just in contact with Acheson Colloids & found the same thing. Sounds like a lost business opportunity to me! I'm trying to electroplate bone, actually {weird art sculpture}. Think I might buzz down to the wood finishing shop & pickup some powdered Al & Cu & try to make my own conductive paint.

Here's links on mirroring..dunno if it'll be conductive enough or not..

Just found this nifty idea on sputtering, I guess you'd have to wrap the oustide of the bottle with foil & maybe use a tube or cylinder of silver or copper down the neck in order to do the sides. Could probably use an old microwave oven transformer & rectifier for the 2 to 3 kV needed.

Forget about Al. The oxide coating will defeat your purpose. Conductive paint can be made with powdered Cu or Ag and graphite in a suitable carrier.

Ted

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.

So, if I used a swab and put a lil bit behind a car door handle..it would be hard for the operator to remove it from their fingers?

That rifle hanging on the wall of the working-class flat or labourer's cottage is the symbol of democracy. It is our job to see that it stays there. - George Orwell

On Sat, 29 May 2004 18:27:11 GMT, Gunner wrote

Same as powdered pencil lead. Mix it with a dab of white heat sink grease (as found at radio shack in little tubes). That stuff is incredibly tenacious and resistant to both solvents and detergents.

Ooof! No, I didn't.

--Winston

I personally think that you guys are giving more credit than is due to Leyden Jars. You will note that they haven't been seen much since the turn of the 20th century, and there are reasons for that.

A Leyden Jar is simply a low value of capacitance capacitor that can handle large voltages. They make in interesting demonstration during a physics lecture when combined with something like a Wimhurst static electric generator, but are today little more than a curiousity.

Unless someone is focused on dupicating 19th century technology, I have absolutely no idea why they would want to duplicate a Leyden Jar capacitor.

Still, duplicating and replicating ancient techonology can be fun!

Harry C.

Tell that to the home-brew Tesla coil folks...

After the alcohol has evaporated it's not as tenacious, but still a pain in the but. Perhaps a cotton ball soaked in the stuff would give you enough getaway time.

BTW this is some good quality stuff when used as a novelty ......or a thread lubricant.

Shawn

Perhaps you could aerosolize gold from a ceramics supplier and fire it at cone 022.. May need thinning with lavender oil to be airbrushed into the vessel

Hey, I've got this old 15KV 30ma Franceformer neon sign transformer sitting here, I wonder what I can do with it... ;-)

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