Fixing Warped Hemispheres for a DIY Van De Graaff Generator

[655piano]

Ok, so I'm building a Van De Graaff generator from parts I've been collecting for some time now. I have 2 hemispherical bowls that were supposed to line up perfectly to make the ball at the top. shipping has warped them just the slightest bit. I'm wondering if this will produce coronal leakage if i just connect them how they are with aluminium tape. That's the other thing, these bowls have no brim to reduce leakage, so would you recommend that I connect them with aluminum tape or something different.

 

[655piano]

this is an image of one of the bowls

 

[zoki85]

Ok, so I'm building a Van De Graaff generator from parts I've been collecting for some time now. I have 2 hemispherical bowls that were supposed to line up perfectly to make the ball at the top. shipping has warped them just the slightest bit. I'm wondering if this will produce coronal leakage if i just connect them how they are with aluminium tape. That's the other thing, these bowls have no brim to reduce leakage, so would you recommend that I connect them with aluminum tape or something different.

Doesn't have to be aluminium tape. It can be ordinary tape, but connect the domes inside with one wire/piece of a metal.
Of course, align the domes to make sphere as perfectly as you can.

 

[655piano]

zoki85, That still doesn't seem like it would solve the leakage problem. The voltage on both bowls will be the same even if they are touching the slightest bit so the wire doesn't seem like it would do much. The charge wants to move to the outside and collect until it needs to discharge. When there is an exposed edge, it will discharge into the air before it reaches its max storage potential. Do you think putting a layer of aluminum foil between the two bowls would work? Even if the layer is wrapped around the seem and then taped on.

 

[zoki85]

Carefully made layer of Al foil would work if it makes no protrusions.

 

[655piano]

Ok thanks, Ill let you know how it works. Might have more questions pertaining to the rollers and belts.

 

[berkeman]

Ok, so I'm building a Van De Graaff generator from parts I've been collecting for some time now. I have 2 hemispherical bowls that were supposed to line up perfectly to make the ball at the top. shipping has warped them just the slightest bit. I'm wondering if this will produce coronal leakage if i just connect them how they are with aluminium tape. That's the other thing, these bowls have no brim to reduce leakage, so would you recommend that I connect them with aluminum tape or something different.

It looks like you are a senior in high school. Do you have a mentor at your school or other experienced person who is helping you with this project? What is your background so far in electricity? What other projects have you built?

 

[655piano]

berkeman, yes I am a senior in high school. I have a few teachers that have inspired me and occasionally answer my questions. I've built bio generators, steam engines, distillation apparatus, a vortex cannon. Currently I'm working on this generator and also approaching my third month working on "The Miller-Urey Experiment". I have a descent background in electricity. Mostly self taught from textbooks new and old. AP Physics has helped a great deal as well.

 

[Dadface]

Try to avoid any pointed bits and keep the surface as smooth as you can. Although the surface will be at an equipotential the electric field strength will be greater at more pointed (smaller radii) places and discharge is most likely to occur at those places. I think by far your biggest problem is in fashioning the area around the hole through which the belt passes. If you look at demonstration Van de Graaff domes you will see that the edges of this area curve inwards.

 

[berkeman]

berkeman, yes I am a senior in high school. I have a few teachers that have inspired me and occasionally answer my questions. I've built bio generators, steam engines, distillation apparatus, a vortex cannon. Currently I'm working on this generator and also approaching my third month working on "The Miller-Urey Experiment". I have a descent background in electricity. Mostly self taught from textbooks new and old. AP Physics has helped a great deal as well.

Good stuff. Sounds like you are on a good path forward.

Safety is a big issue when working with high voltage. Be sure to keep safety in mind as you work your way through this project.

 

[dlgoff]

... would you recommend that I connect them with aluminum tape or something different.

If the hemispheres are made of aluminum (not able to solder), make some sort of fixture to hold them in the correct position and use epoxy (use a procedure that would apply it to both parts, mostly on the inside, so it (epoxy) will run together when in fixture to cure).