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LAN_403

audio:deviant

Tue Apr 21 2009, 10:49PM

Registered Member #2081 Joined: Wed Apr 15 2009, 11:36AM
Location:
Posts: 78

hello hello. was just looking into constuction of the top load and have a couple ideas. this is for a drsstc

that kind of top load
a mesh one

make a toroid out of that

or just ducting.

does it not even matter?

Plasma Lover

Tue Apr 21 2009, 11:14PM

Registered Member #1911 Joined: Mon Jan 05 2009, 06:30PM
Location: Salem, Oregon, USA
Posts: 165

How about a toroid like this? They seem fairly easy to build -

http://www.sky-chaser.com/tcpart8.htm

You don't have to cover them in foil and, if you make them right, they look really pretty. Depending on the size of the toroid you need, this would work out great with the same 1/4" pipe used for our primary coils, and 1/8" would likely work even better. The reason I say it would work well is that the copper pipe is already curved, so you don't have to worry, as much, about kinking it. Just make sure you put the copper tubes in at a fairly high density so that the entire assembly has electrostatic shielding.

Just a thought...

Herr Zapp

Tue Apr 21 2009, 11:18PM

Registered Member #480 Joined: Thu Jul 06 2006, 07:08PM
Location: North America
Posts: 644

a:d -

It should be obvious that whatever material is used for the topload, it must be electrically conductive.

Your "fly-screen" material is fiberglass, and useless for a topload unless it could be somehow made conductive. Additionally, this type of screen is designed to be used as a flat panel, and cannot be easily formed into a complex three-dimensional shape like a torus.

Regards,
Herr Zapp

tesla500

Wed Apr 22 2009, 01:27AM

Registered Member #347 Joined: Sat Mar 25 2006, 08:26AM
Location: Vancouver, Canada
Posts: 106

Plasma Lover wrote ...

How about a toroid like this? They seem fairly easy to build -

http://www.sky-chaser.com/tcpart8.htm

I've built a toroid like this, and I have two words: Never again! It took about 15 hours of labor, and tons of drywall compound and aluminum tape.

Just get flexible aluminum duct, it's about half an hour to build, and works very well. For toroids up to 6" minor diameter you can get the duct at Home Depot. If you want a toroid bigger than 6" minor diameter, you can get larger flexible duct from HVAC suppliers.

David

audio:deviant

Wed Apr 22 2009, 10:21AM

Registered Member #2081 Joined: Wed Apr 15 2009, 11:36AM
Location:
Posts: 78

yeah sorry was ment to put a link to an aluminum mesh. that copper one does look well complicated! i wanted something that looks pretty slick, spose the ducting would be fine for now. can always change it. i do like the look of that first one.

i know they cant have anything pointy. but do they have to be solid?

Plasma Lover

Wed Apr 22 2009, 03:34PM

Registered Member #1911 Joined: Mon Jan 05 2009, 06:30PM
Location: Salem, Oregon, USA
Posts: 165

tesla500 wrote ...

I've built a toroid like this, and I have two words: Never again! It took about 15 hours of labor, and tons of drywall compound and aluminum tape.

David

But, David, you have to realize that this would go much more smoothly with copper soldering skills. My father has copper solder and believe me, it would work much better than drywall compound and aluminum tape. You don't have to cover them, if you have no points sticking out. They electrostatically shield themselves.

As for whether or not you need to fill an aluminum duct toroid, you do not, but if you fill in the crevices with something along the lines of expanding foam, epoxy, or something cheaper that works as well, then you can cover it with aluminum tape and smooth it out with a spoon, or something along those lines. When you do so, it will be very shiny and your toroid will look similar to a spun aluminum toroid, and will be stiff, as well. The only problem with this design is that it uses a LOT of aluminum tape.

tesla500

Thu Apr 23 2009, 02:30AM

Registered Member #347 Joined: Sat Mar 25 2006, 08:26AM
Location: Vancouver, Canada
Posts: 106

Plasma Lover wrote ...

But, David, you have to realize that this would go much more smoothly with copper soldering skills. My father has copper solder and believe me, it would work much better than drywall compound and aluminum tape. You don't have to cover them, if you have no points sticking out. They electrostatically shield themselves.

I did have a form, but it wasn't copper. It was 8" dia flexible duct, like big dryer duct, anchored around a wood center piece to hold it rigid while coating. I found the resulting toroid was very susceptible to dents, much more so than aluminum flexible duct, mainly because the drywall compound based toroid is heavy and has a lot of inertia if you bump anything.

I can't think of anything simpler than just bending a flexible aluminum duct around into a toroid, if you want anything better, you may as well just get a proper spun toroid. For flexible duct, there's no need to coat the entire thing with foil tape, the roughness is very small compared to the toroid's size, and won't effect the electric field gradient that much. I built one fully covered with tape, and it looked nice for awhile, but the duct slowly compressed and the tape lost all the smoothness, so I don't see much point of taping the whole thing.

David

Cesiumsponge

Thu Apr 23 2009, 04:36AM

Registered Member #397 Joined: Wed Apr 19 2006, 12:56AM
Location: Western Washington
Posts: 125

You can try copper mesh material. It comes in a roll and it's used to plug up holes and cracks in homes to prevent vermin and rodents from getting in. You can probably wrap it around any torus form like a bandage, then insert a center support. Also good stuff for RF shielding.

There is also this style open-frame, hollow toroid construction (besides the ring type). It's composed of disks.

Plasma Lover

Thu Apr 23 2009, 03:20PM

Registered Member #1911 Joined: Mon Jan 05 2009, 06:30PM
Location: Salem, Oregon, USA
Posts: 165

Cesiumsponge wrote ...

You can try copper mesh material. It comes in a roll and it's used to plug up holes and cracks in homes to prevent vermin and rodents from getting in. You can probably wrap it around any torus form like a bandage, then insert a center support. Also good stuff for RF shielding.

There is also this style open-frame, hollow toroid construction (besides the ring type). It's composed of disks.

That copper mesh would be cool to coat a topload with, especially if said topload were otherwise non-conductive. I just find the auction name somewhat funny: "Stuf-Fit Copper Mesh For Rat Mouse Bat Control..."

I want a RatMouseBat to control. I wonder if a RatMouseBat is in the same phyllum as kangarabbitmousquirrel -

Tom L

Sat Apr 25 2009, 01:52PM

Registered Member #1931 Joined: Thu Jan 15 2009, 03:11AM
Location: Hobart Tasmania
Posts: 6

I've used a truck exhaust bend doughnut successfully. It's a spun steel toroid made in two halves, machine welded round the inside and outside of the major circumference and ground back to a smooth finish. When manufacturing custom truck exhausts sections are cut out of the toroid to provide the required bends in the exhaust system.

I welded a steel disc in the centre (the toroid has a doughnut hole) and had the whole thing nickel plated, mostly for show. Apparently they had trouble with it floating in the plating bath!

Pic here:

Aside from being a little heavy, the only other drawback is that it is difficult to source sizes above 16" x 5".

I want to use semi-rigid aluminium ducting for my planned DRSSTC's 24" x 6" (or larger) top load, like this stuff:

I've seen some very neat top loads made with this type of material but I'm wondering how to join the ends together to form the toroid and how the centre disc is best attached?

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