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Re: [TCML] Is It Polyethylene?

Thanks for the informative replies.  Good stuff all.  This list is a goldmine of accumulated knowledge & experience on nearly any technical subject.

Anyhow, I first ran a microwave oven test, 1 minute at full power.  I placed a small stack of my unknown plastic next to a cup of water.  The water nearly boiled.  The plastic did not warm up at all.  Whatever it is, it's perfectly transparent to 2450MHz RF.

Next I tried the flame test.  A strip of the stuff burned quickly with a smokeless yellow flame.  Little flaming bits dripped away with a "zipping" sound.  It smelled like hot candle wax.  It's polyethylene alright, or "polythene" to our UK cousins (so what happened to the missing "ethy", hmmm?)

Close inspection of the PE sheet did indeed reveal contamination with embedded mystery bits of something that looks like sawdust.  However, it's mostly clean & clear.  I should be able to use at least 90% of it.

If I come up with a serviceable cap, I'll share it with the list.  On the other hand, If my caps blow up and spew oil all over my garage, I'll discard the evidence and deny any involvement with homebrew caps!

> --- On Fri, 2/6/09, Bert Hickman
> <bert.hickman@xxxxxxxxxx> wrote:
> > From: Bert Hickman <bert.hickman@xxxxxxxxxx>
> > Subject: Re: [TCML] Is It Polyethylene?
> > To: "Tesla Coil Mailing List"
> <tesla@xxxxxxxxxx>
> > Date: Friday, February 6, 2009, 8:23 PM
> > Hi Greg,
> > 
> > It's undoubtedly polyethylene sheet. Two pieces
> should
> > feel very slippery when rubbed together (its sometimes
> > called the poor man's Teflon). To further confirm,
> take
> > a small strip and try to ignite one end with a match
> or
> > lighter. Vinyl will not burn, but will melt and
> blacken and
> > give off acrid fumes (poisonous - Hydrogen Chloride).
> > Polyethylene will catch fire and burn  with a
> bluish-yellow
> > flame, melted material will drip flaming droplets, and
> it
> > will give off a smell similar to burning candle wax.
> > 
> > Be sure to examine your material carefully to make
> sure
> > it's virgin material and not recycled. The latter
> often
> > contains embedded dirt, and sometimes even metal
> debris,
> > that can cause early dielectric failure in your home
> brew
> > cap.
> > 
> > Bert

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