Homemade plate caps

[billybob]

Hello again, I have eighteen 8 inch by 5 3/4 inch plexiglas plates that I want to make two 9 plate capacitor banks for a smaller Tesla coil.
Would glueing the 6 inch by 4 inch aluminum foil strips directly to the plexiglas work? I have marine epoxy that says to work well with these material. If you think that will work I will glue a thin layer on the bottom and top of the aluminum foil as well as the edges.
Finally do you think I should make one large cap? Two caps? Or three 6 layer plexiglas caps?
Thank you,
Ben

 

[Visitor]

How thick is the plexiglass?

 

[billybob]

How thick is the plexiglass?

Well that’s hard to say exactly...

 

[billybob]

Beautiful thumb I know.

 

[billybob]

Also here is a picture.
I think I’m going to put it in a small container or something filled with oil.

 

[shortbus=]

If you go with the Plexiglas, won't you need to refigure the calculations for the capacitance? Since Plexiglas/Lucite(same thing different companies) is lower than glass in dielectric strength.

Dielectric Constants Of Various Materials Table

Dielectric Constants Of Various Materials Table

www.csgnetwork.com

 

[billybob]

If you go with the Plexiglas, won't you need to refigure the calculations for the capacitance? Since Plexiglas/Lucite(same thing different companies) is lower than glass in dielectric strength.

Dielectric Constants Of Various Materials Table

Dielectric Constants Of Various Materials Table

www.csgnetwork.com

What about this though? http://teslauniverse.com/build/plans/make-your-own-high-voltage-capacitors

 

[billybob]

I made a glass plate cap and it does ok but there is a lot of corona discharge and a few arced even with almost two inches spacing from edge of glass

 

[shortbus=]

I made a glass plate cap and it does ok but there is a lot of corona discharge and a few arced even with almost two inches spacing from edge of glass

How did you clean the glass before making it? While not really a conductor Super Glues do conduct especially at high voltages, so if you used super glue and didn't wait for it to out gas before stacking the plates you may have caused pathways for corona.

 

[billybob]

How did you clean the glass before making it? While not really a conductor Super Glues do conduct especially at high voltages, so if you used super glue and didn't wait for it to out gas before stacking the plates you may have caused pathways for corona.

Well I dampened a cloth to clean the glass then dried it off. I didn’t use glue.

 

[Visitor]

Cleaning the glass with isopropyl alcohol (rubbing alcohol) would probably be good idea. It will dry quickly and leave a clean surface.

 

[billybob]

Cleaning the glass with isopropyl alcohol (rubbing alcohol) would probably be good idea. It will dry quickly and leave a clean surface.

Does that go for plexiglas? Also the Dielectric constants chart you have above suggests glass having a higher breakdown voltage than plexiglas, but I had really cheap dollar tree glass frames does that make a difference and the link I sent suggest plexiglas to have a higher breakdown voltage or am I misreading it?

 

[shortbus=]

link I sent suggest plexiglas to have a higher breakdown voltage or am I misreading it?

No, you're comparing apples to oranges. Dielectric strength and breakdown voltage are two different things. https://materion.com/-/media/files/...dielectric-strength-materion-tech-tidbits.pdf

 

[billybob]

No, you're comparing apples to oranges. Dielectric strength and breakdown voltage are two different things. https://materion.com/-/media/files/...dielectric-strength-materion-tech-tidbits.pdf

Oh ok thanks!

 

[billybob]

Well, I'l be glueing the plexiglas plates this evening with the resin/epoxy mix. I'll trim the corners so there is no sharp edges on the foil and I think I'll make two caps. Once I find a container I'll submerge the caps in oil.
Does making two caps reduce the risk of arcing? Or does that not have a factor?

 

[MacIntoshCZ]

what about leyden jars?

 

[billybob]

what about leyden jars?

Those are basically beer bottle caps right?

 

[MacIntoshCZ]

right

 

[billybob]

Those are basically beer bottle caps right?

I thought about those, but they would take up a lot of space, as well as they can get heavy, and I might as well do something with the supplies I have. Next time I think I'll try a cap that I saw with plastic cups and foil. Even though it's incredibly cheap the results seem pretty good.

 

[MacIntoshCZ]

I would rather use glass than plastic