Re: The Geek's Guide to NST's - was- Strange neons

["acmnovak" <acmnovak-at-msn-dot-com> (by way of Terry Fritz <twftesla-at-uswest-dot-net>)]

> >you have described them to a T. is the best way to depot these badboys
with
> >the freeze and chip method?
>
> Personally I abhorr (sp? who cares) the freeze and chip method. I have
> killed a LOT of NST's (and FITs, and computers, and Lasers...etc ad
nauseum)
> so I spend a lot of time depotting them. Here's what I have learned....
>
>
> The Golden Rules of Depoting.
>
> 1. Never freeze and chip. Every time I tried this (both of them) resulted
in
> damage to the NST. Work them hot, not cold.



The reason this did not work was you forgot a crucial detail: Short the HV
leads and plug 'her in for sometime to heat the core of the transformer, and
thus the inner most layer of tar. When you chip off the tar, all of it comes
off except a thin layer of tar residue on the core and whatnot. This can be
removed cleanly by placing the unit in a washpan and applying kerosene with
a toothbrush or old rag.


> 2. Never bake them indoors! Unless you LIKE the stench. If you do, get
used
> to it. It lingers like a fart in church. If you bake one in an oven don't
> expect to make anything edible in there for a long while.


diddo


> 3. Start before noon, it takes a while. I average about 4 hours min.

> 4. Keep it hot. Once you start, you have to keep an eye on it for safety.
> It's a LOT easier to do the major cleaning hot.

> 5. Wear old clothes. Tar sticks to everything. It's like vaseline with an
> attitude. And it does NOT wash out easily.

Yup, the best thing is not to touch it at all. Treat it like toxic waste:
wair a big heavy shop aprin, leather gloves and a gas mask:)


> Here's the method I use.
>
> I place an old electric griddle in sandy/gravel area (it's a lot easier to
> clean up tar from sand than concrete). Near the house, on a side with
CLOSED
> windows.
>
> Place the Griddle on something solid (cinderblocks) and make sure the
entire
> griddle is supported. Don't try to balance it on 1 block.
>
> Go to Meijers (or whatever) and get a few of the stamped Al-foil baking
tins
> used for turkeys and roasts. You will use them in pairs, get 4 or more,
> they're cheap.
>
> Place one of them on the griddle, place 1 - 3 NST's inside, place another
> roasting tin inverted on top to seal in the heat.


I would recommend putting the heater on the NST, not vice verca... If you
balance things right, all the tar drips off without a fight. For cleanup all
you do is throw away the pan and take the (cooled) nst over to the washpan
full of kerosene or gas or whatever.


> Bake at 400F untill it starts to stink real bad. Check it every half hour
to
> start, then (after about 3 hours) every 15 min.
>
> You will need a stick (1/2 dowel works great) and a coffee can.
>
> IMPORTANT NOTE:
> When the tar is melted there is nothing to hold the core in place! If you
> invert the NST EVERYTHING will fall out and you WILL rip hair thin wires
> off. This is bad.
>
> By now the tar will either be VERY soft or goopy (technical term for a
> gelatinous state). Use the dowel to GENTLY schlop off bits of tar. If you
> feel it snag on ANYTHING then don't FORCE it! There are little wires in
> there that break VERY easily. Take your time.
>
> The Insulators on the end should turn by now. Turn them about 1/4 turn and
> pull GENTLY. Pull them JUST clear of the case and cut the wire CLOSE to
the
> bolt on the insulator. Set them aside.
>
> Lay the NST on it's side and let the tar run out into the coffee can. Save
> this, you may want it. (goes well with feathers)
>
> When you have the vast majority of the tar out, cut the wires for the
> primary and center tap (primary will be the 2 big ones, tap will be 2
little
> ones to the case) then remove the CORE.
>
> The CORE will be a big iron thingy with 3 spools of wire on it. About the
> weight of a brick. It is the actual NST. The Middle spool is the primary
> (heavy wire, low voltage). The end spools are each secondaries (high
> voltage, hair thin wire). Each secondary is HALF of your rated voltage
> 7500VAC for a 15/30 NST.
>
> Set the CASE back on the griddle and cook untill you can pour out all the
> tar. IF you want to put it back in there. I prefer a new case, homemade
from
> Lexan and oil tight.
>
> Scrape all the tar you can off the NST. It's easiest to do it now while
it's
> too hot to touch. Be careful!
>
> Let everything cool untill it's room temp.
>
> I clean my NST's manually. Some soak in Gas or Kerosene, but that's tha
lazy
> way and takes forever.
>
> Clean everyting as good as you can. If you take your time (a weekend) you
> can get it almost pristine. But you REALLY have to want it.
>
> If you're lucky, there will be a couple sets of metal shims that can be
> removed from the core. These are current limiting shunts. DO NOT REMOVE
THEM
> ALL!!!! This is where potting in Oil is a wonderful thing. When you
> reassemble the NST you can remove it from the oil, remove A SINGLE PIECE
OF
> METAL FROM EACH SET, NO MORE and test everything to see how it works. If
it
> gets HOT than you went too far. Romove only one set of shunts at a time.
> They have to be removed in sets though, not just a single sheet from one
> bundle, but one sheet from each bundle. Everyting must be balanced.


Oh c'mon... Only one shunt? That's no fun, I removed up to 20 with no fires!
12/60--->12/250!!!!!


> Not all NST's have EASILY removeable shunts, some require a grinder,
torch,
> or grenade.
>
> Examine the NST throughly. Test it naked with low voltage from a variac.
If
> it works after depotting alone then you had a Carbon Track in the tar.
it's
> fine now. IF not then you have either an OPEN (broken winding from over
> current) or SHORT (2 ajacent windings touching or carbon tracked, or even
> welded from over voltage). There are only 3 basic failure modes for NST's.
>
> You can repot in everyting from Mineral oil to Vaseline (it melts like
> butter) to the original Tar (if your masochistic).
>
>
> HOWEVER:
>
> The BOX type NST you have is MUCH easier. Just Bake it and there are NO
> insulators or wire connections to deal with, only the midpoint case
Ground.
> MUCH easier to depot.
>
>
> btw, if you use a SAFETY GAP, an NST FILTER (like Terry's) and Follow the
> rules of NST life support, you won't kill them. I haven't killed one in
> Months!
>
> Rules of NST Life Support
>
> 1. Use a PROPERLY SET Safety Gap and DON'T MONKEY WITH IT!
>
> Set the Gap to where it JUST BARELY does NOT fire with the NST connected
to
> it. Then LOCK IT THERE AND NEVER MESS WITH IT! If you're properly set and
it
> starts to fire then you're DOING SOMETHING WRONG and it's doing it's job
in
> Telling you this. If you simply open it more and more you have defeated
the
> purpose of having one in the forst place.
>
> 2. NEVER use a NON-Synced Rotary Gap with a NST. They allow the voltage to
> get too high and WILL kill it in minutes.
>
> 3. KEEP YOUR WIRES SHORT! Keeping your leads as short as possible (1' or
> less) for some reason beyond my understanding DRAMATICALLY increases the
> life of an NST. I don't know why, I know it works. Ask the Glass Benders
for
> the details if your interested.
>
> Some brands of NST's are MUCH more fragile than others. France is the
worst
> (but the easiest to modify and depot), I swear by my Jensons, I love them,
> but they have NON removeable Shunts and are a pain to modify.
>
>
>
> Alright guys, what did I forget?
>
> Christopher A. Boden Geek#1
> President / C.E.O. / Alpha Geek
> The Geek Group
> www.thegeekgroup-dot-org
> Because the Geek shall inherit the Earth!
>
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