[Prev][Next][Index][Thread]

Re: NST insulations



Mike:
	One of the better sources for commercial waxes with
a good assortment of selectable properties for very reasonable
prices are jewelry supply houses.

The waxes they offer are usually destined for making rings
and other injected, carved and cast "lost-wax" products, but
I found the waxes clean and easy to use.

They vary in hardness and dryness, etc. and are usually color
coded, but no two mfg are the same.  Look in the ftp dir below
for some pdf files with specific info and costs and phone#s:

  ftp.mindspring-dot-com/users/ottalini/highvoltage/misc/wax

Take a look on the web as well.  Many jewelry supply houses
carry it in bulk, so check in your phone book or on the web.

The bulk HV value of those particular waxes is unknown to me,
but I have some here and could do some tests this weekend.

I do know that HP used a wax for HV protection inside one of
their older HV probes, and many small commercial HV transformers
are dipped in a very pure wax something like bee's wax, partially
to protect the fine 40-42awg wire, partly to minimize the added
inter-winding capacitance (big problem for tiny HV transformers)
and partly to give a little added calorie advantage when the
transformer gets hot (it takes more energy to melt the wax).

I also have some real bee's wax here, so I can test it at the
same time for HV properties.  I'll concentrate on 15KVAC, 60Hz.

One problem with wax is that it will burn if things get too hot
(potentially flammable at 177C typ), but then so will mineral oil
(flash point 245C).

The best HV potting compounds are still silicone rubbers, but
unfortunately they cost big time.  Typically 5Gal = $500.00.

*---------------------------*
* Kevin Ottalini            *
* WhoSys / Who Systems      *
* High Voltage with Style!  *
* ottalini-at-mindspring-dot-com   *
* Often in Another Reality  *
*---------------------------*

----------
> From: Tesla List <tesla-at-pupman-dot-com>
> To: tesla-at-pupman-dot-com
> Subject: Re: NST insulations
> Date: Tuesday, March 07, 2000 5:41 PM
> 
> Original Poster: "Mike Nolley" <mnolley-at-mail.slc.edu> 
> 
> The thread about de-potting NST's sparked a question about potting
compounds---
>     Does anyone know a relatively cheap source of paraffin, besides
> candles?  I'm
> planning to eventually pot my power supply in something that is
non-toxic, and
> won't leak.  I have heard about mineral oil + poly combinations, and I
may go
> this route if I haven't yet found candles, or some other source of
paraffin
> which
> isn't prohibitively expensive.
>             --Mike
>