Re: stacked poly cap

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "by way of Terry Fritz <twftesla-at-qwest-dot-net>" <Esondrmn-at-aol-dot-com>

In a message dated 9/5/01 6:49:19 PM Pacific Daylight Time, tesla-at-pupman-dot-com 
writes: 


>
> > 
> > I was thinking of building a stacked poly cap using the HDPE sheets 
> > available 
> > from McMaster-Carr. I wanted to use the 1/16" thick sheets. They are 
> pretty 
> > cheap ($1.67 I think.) Does anyone know what voltage the sheets should be 
> > able to withstand? I haven't been able to find reliable information on 
> the 
> > dielectric strength of HDPE. Almost everything I have seen has a had a 
> > different value for the dielectric strength. Also, I was wondering if 
> > someone 
> > could give me the formula for calculating the capacitance of a plate cap. 
> >                                    Justin 



Justin, 

I have built rolled poly caps out of the .062" thick HDPE - and blew two of 
them.  My opinion is that one layer of .062 is only good for 9 kv to 10 kv in 
Tesla coil service.  Now, two layers of .062 is bullit proof.  Three layers 
of .030 material would be ideal for 12 to 15 kv. 

Ed Sonderman