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Re: Home brew capacitor
There are other types of "inhibited" mineral oil that have their own nasties
in them. I have had no experience with them, only in the literature.
On some of our manuals it says not to use askerals (sp) as they may
dissolve the acrylic parts. Fortunately I have never tried this. On a
humongous Marx generator that I worked on at the University of Maryland
the oil got hot in some tanks. When the RG-8 cables were replaced
the polyethylene had turned to wax! You could strip the wire by hand!
The power supply that came from hypotronics uses RG-34 polyethylene
cables in Shell Diala AX oil with no problem.
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: Sunday, October 06, 1996 9:02PM
|
|<<File Attachment: 00000000.TXT>>
|> Subject: Re: Home brew capacitor
|> |Subject: Re: Home brew capacitor
|> |Subject: Re: Home brew capacitor
|
|From bert.hickman-at-aquila-dot-comSun Oct 6 13:16:27 1996
|Date: Sat, 05 Oct 1996 16:46:00 -0700
|From: Bert Hickman <bert.hickman-at-aquila-dot-com>
|To: tesla-at-pupman-dot-com
|Subject: 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 --
|