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PE or not? Cap Experiments



Hi Robert, Bert, Bart, Mark, John F, All

Well I redid the burn and tried the float test.

Both materials will float in water, altho the thicker stuff will "surface"
faster.

The thick stuff definately smells like wax when ignited. The thin stuff is
harder to ignite and does not really have the "distinct" wax smell. I canīt
really describe itīs smell. The kernal of both flames is blue/yellow. The
outer flame is yellow and slightly sooty. After extingushing the flame the
thick stuff keeps itīs paraffin oder, where as the thin stuff had almost no
smell at all. Both plastics are non soluable in:

1.) Acid (HCL/H2SO4/HNO3)
2.) Base (NaOH)
3.) Gasoline or Benzene
4.) Acetone or turpentine

(I did not expect it to be, but I wanted to be sure)
 
Bert wrote:

Probably NOT, since it seems to have much more dielectric loss than LDPE
based upon the powered-up experiment you performed. You may have
something similar to Saran wrap (which is often Polyvinylidene Chloride,
and which has his a high dielectric loss similar to PVC)...

c.) why is the "effective" dielectric K of the thin stuff less than 1 (K of
air) 

The combination of entrapped air and increased thickness?

> (one was even tested under oil !!) that have gotten so hot, that they have
> melted!! They got so hot that I burned my hand (after 5 min of cooling time)
> while unwrapping them, to see why they had died. 
<SNIP>

This definately does NOT sound like LDPE...

Thinner LDPE should work, if you can get out the trapped air. Some
coilers have even used thin LDPE baggies for their homemade caps. The
caps I use have multiple sheets of 4 mil LDPE. The thin material you have is
almost certainly not LDPE - what was the original use that this material was
being sold for? 
SNIP

To Bert:

I am starting to suspect that the thin material is not PE at all, but rather
as you mentioned Polyvinylidene Chloride. This would certainly explain the
heating of the dielectric. I donīt think it was entrapped air (my question to
why k<=1) as I was only using one sheet of plastic per AL foil in my test cap
and the second cap (only difference was the thick LDPE) did not exhibit these
results.

The thin stuff comes in a large sheet (12m x 4m). It is sold as covering sheet
(for furniture, etc). It is used during paint jobs to keep splattering paint
from ruining your expensive furniture. So it could be anything. The bag it
came in says PE, but maybe they are only talking about the bag material. In
germany bags, plastic packaging, etc have to be marked (what they mainly
contain), because of our recycling rules.
 
 To John Freau:

I too would guess that the blown Plastic Caps used mylar. Itīs hard to tell
what color it originally was (as they were oil filled) The color (now) is
brown / yellow and slightly transluctiant.


coiler greets and thanks from germany,
Reinhard