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500,000 volt Van de Graaff Generator Using Cheap Parts

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Step 2: Belt Material and were to get it!

I had several questions about the belt material, and its the most important piece to the VDG next to the sphere.

What you need is 18 oz. Vinyl Coated Polyester

A very tough mesh fabric that is coated with vinyl making it waterproof with a high resistance to dirt, mildew, oil, salt, chemicals and UV. Outstanding strength. Made of top quality materials, will not tear, stretch, crack, rot or mildew. May be sewn or glued with HH-66 vinyl cement.

Were you can get it!!!

They have a 42 oz. version but I have not tried it.

I got mine in white, almost all the black materials I tested didn't do so well.
 
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I have one question: How did you get close to 900kv with this small 12" sphere? It is just impossible, for instance the absolute maximum theoretical voltage you could get out of a 12" sphere is V = 3x106r= maximum of 450kv but in reality it would fall below 300kv.... How come you got huge sparks, you see?
BG23 years ago
I have the belt off an old treadmill... Would that work?
nickademuss (author)  BG23 years ago
nope
junk2504 years ago
I just listed the Sargent-Welch Van De Graaff for sale, Google it .
junk2505 years ago
nickademuss, hello,found this thread looking for info on a Sargent-Welch VDG Electrostatic generator I found at a thrift store the other day. Its tube is 24" and the sphere is 10". I have a couple of questions you might help me with, the top half of the sphere was missing so I just found a stainless mixing bowl that would sit on top and it works excellent ! My question is how important is the "seal" between the two halves because it only fits loosely but doesn't appear to effect the charge buildup?(it might be a cheap alternative to buying the gazing ball for your build,just attach 2 mixing bowls together somehow,you can pick up cheap stainless mixing bowls for a couple of bucks at a dollar store)How best would that be done ? I don't understand the science behind how the charge is contained,but I have heard that it will leak from any sharp exterior points.Even with the top half fitting loosely this thing will throw a spark 5-6" easy !!! I assume it is leaking some because if you stand close and let it run you slowly feel your hair standing up anywhere within 2-3 feet of the machine,and I can feel the charge running through my skin.If I put my arm hair about a foot away,hair stands erect as hell,and as you move closer the hair starts dancing around going flat-erect-flat until you get to about 6" then ZAP !! I don't know exactly how much voltage that would be,I'm guessing 300,000-400,000 or more,pretty cool. I'm not into electronics really but these machines are pretty cool,I had an absolute blast with the neighbors kids the other day,I laughed so hard I think I peed on myself. One more question,my machine has a variable rheostat control and when plugged in but turned all the way down/off,the whole base of the machine gets rather warm/almost hot, is this normal and what is wrong if anything? The only way to keep it from getting hot is to unplug it(it doesn't get hot if the rheostat is in the running position). I had never seen this site before its cool,and your builds are awesome also !
nickademuss (author)  junk2505 years ago
The sphere being smooth is very important, on mine I can demonstrate this by taping a thumbtack to the sphere tip out. All the charge will go to the tip of the tack and bleed off in the form of plasma, it does not focus a spark at all. So the brim of a bowl can have the same effect. The charge will build up better on a smooth sphere. I built a smaller one years ago and used two bowls you could hear it pop and crackle allot and the sparks were about 4" long. I replaced the bowls with a 8" sphere and got 6" sparks. If you do get a matching bowl for the top make sure it has no brim, you could also use metal tape to seal the gap, but trust me a sphere works very well. The absolute best and very hard to find is a torrid or flattened sphere. You should look for an IKEA bowl they have no brim. Also post a pic of the one you have. The base heating up is probably due to a large resistor type speed control, and the heat is normal. Its like the speed control on large slot cars. I also love this site and thanks for the kind words about my builds.
joeogio5 years ago
im building a vdg similar to yours and i tried using elasic band its 63% polyester should it work
gepp5 years ago
How big of a piece of that 18 oz. Vinyl Coated Polyester do you need?
nickademuss (author)  gepp5 years ago
you will need at least 65" of belt material 2 to 3" wide. the column is 24" tall so double that and add a few for roller length and such.
killbox5 years ago
black ones may have i high iron nickle or carbon content which may bleed your static.
laci375 years ago
I think you can use any type of plastic fabric, but voltages may vary.