Re: RE- Re: Polyethylene
Subject: Re: RE- Re: Polyethylene
Date: Mon, 16 Jun 1997 18:29:00 GMT
From: robert.michaels-at-online.sme-dot-org (Robert Michaels)
Organization: Society of Manufacturing Engineers
<The otherwise esteemed and appreciated Alfred Skrocki takes umbrage>:
T>> The melting (and for that matter, welding) of polyethylene
T>> is done under a nitrogen atmosphere or blanket for this
T>For anyone contemplating melting down polyethylene milk jugs to mold
T>into capacitor plates it should be relatively easy to make and air
T>tight glove box and flood it with nitrogen before melting the jugs.
T>Of course one would have to use electric hot plates since nitrogen
T>won't support compustion.
It would be possible, practical is another matter. If any
are serious about this, the use of carbon dioxide ought
to be considered. Nitrogen is used industrially (it's avail-
able from welding supplies dealers) but carbon dioxide is
generate-able at home with little trouble.
T>> If one were intent upon making one's own polyethylene film
T>> at home in one's spare time (about as sensible as making
T>> one's own 100-w lightbulbs - IMHO):
T>The reason for even considering it is because some people like those
T>in Australia for example have great difficulty getting usable
I'm frankly incredulous. Unless one is talking about the
outback, Australia is =quite= civilized. Sydney for example
is about as urbane and sophisticated as city could be --
I beg edification from any better informed.
I humbly apologize to all our Australian friends for
the implication contained in your post!
- - - - - -
T>I've been of the impression that polyethylene was a thermo-setting
T>plastic and as such required a raised teperature to crosslink the
Au contrare!! It's a classical example of thermoplastic.
Tho I believe that, in desperation, it is possible to
make cross-linked polyethylene. Such would be none too
easy as genuine polyethylene would not have any cross-
linking sites on the polymer backbone.
T>> Then go have your head examined.
T>I'ts all relative Robert, if one can't find useable polyethylene then
T>it is not so crazy to try and make it, besides if one did find an
T>easy way to recycle polyethelene milk jugs into H.V. capacitors
T>it would be of great assistance to the environent.
Let me give you a far-field example -- why I believe my
"head examined" quip is not as sarcastic as you may be
(all too) willing to believe.
Coca-Cola is to be found in virtually every country in
the world, with precious few exceptions. It comes in
plastic bottles. Such is the extent to which civiliz-
ation has penetrated the world community.
It is very difficult to picture a country where one can
buy Coke, but could not find a plastic bag or two.
| To put it differently -- if one is in |
| a part of the world were plastic bags |
| are scarce, one will have a =very= hard |
| time mounting a Tesla coil, irrespec- |
| tive of the polyethylene - IMHO |
The world -- hey, I've been