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Re: Home brew capacitor
Tesla List wrote:
>
> >From Benson_Barry%PAX5-at-mr.nawcad.navy.milSat Oct 5 09:15:26 1996
> Date: Sat, 05 Oct 1996 09:20:00 -0400 (EDT)
> From: Benson_Barry%PAX5-at-mr.nawcad.navy.mil
> To: tesla-at-poodle.pupman-dot-com
> Subject: Re: Home brew capacitor
>
> There is a 10kw 100kv power supply here that has been immersed in Shell
> Diala AX
> for over 10 years. Its innards are packed with acrylic sheets, standoffs,
> and spacers.
> I haven't seen any signs of attack as yet. Must be very minute. I do know
> that
> a non thermally stress relieved piece of acrylic with tapped threads in it
> will crack
> into a zillion pieces if immersed in methyl denatured alcohol sold in
> hardware stores.
> Barry
>
> ----------
> |From: "tesla-at-poodle.pupman-dot-com"-at-PMDF-at-PAXMB1
> |To: Benson Barry; "Tesla-list-subscribers-at-poodle.pupman-dot-com"-at-PMDF-at-PAXMB1
> |Subject: Re: Home brew capacitor
> |Date: Friday, September 27, 1996 3:59AM
> |
> |<<File Attachment: 00000000.TXT>>
> |From MALCOLM-at-directorate.wnp.ac.nzMon Sep 23 22:19:42 1996
> |Date: Tue, 24 Sep 1996 07:38:43 +1200
> |From: Malcolm Watts <MALCOLM-at-directorate.wnp.ac.nz>
> |To: tesla-at-pupman-dot-com
> |Subject: Re: Home brew capacitor
> |
> |Bert Hickman wrote....
> |
> |> Also, I think Perspex is the same thing as Plexiglas (Polymethyl
> |> Methacrylate - PMMA). My plastics supplier's chemical resistance tables
> |> indicate that PMMA is slowly attacked by transformer or mineral oil,
> |> which is why I opted to use PVC seperator plates instead. However, I've
> |> never heard of any coilers having oil leakage failures when using
> |> Plexiglas top plates on the rolled caps...
> |
> |Ouch! I've got my plate cap in a perspex container. So far it seems
> |OK with transformer oil but I'll keep an eye on it. Thanks for the
> |warning.
> |
> |Malcolm
> |
> |PS - Welcome back Ian.
> |
Barry,
Well, that's certainly encouraging! Maybe the problem only occurs in
combination with elevated temperatures or with certain brands of
transformer or mineral oil. The catalog I referenced was from Laird
Plastics. They have a fairly extensive Technical Data Section. The
Chemical Resistance Tables (at 73 degrees F) indicated that Acrylic
"decomposes or dissolves in a short time" in transformer oil.
Polycarbonate (PC, Lexan, Lucite) shows "moderate attack of appreciable
absorbtion. Material will have limited life" in mineral oil.
However, I still haven't heard of anyone running into this problem for
either plastic (yet...).
Safe (and solvent-resistant) coilin' to ya!
-- Bert --