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Re: [TCML] Lacquer



no no no - too hard, as you say. make a box out of 1" plywood with a hinged lid and a rubber seal on the hinged lid - put everything inside - bring power to the motor out by putting two screws all the way through the plywood. make a small porthole (maybe 2 inches) and inset it 1/4 inch into the plywood lid, seal with RTV. close up and test to make sure it holds (I'm sure it will but I didn't do any calculations) - now, with the lid open, put in your coil, turn on motor and apply epoxy - when it's all applied, close lid and turn on vacuum pump. the vacuum will pull the lid down hard against the seal so there will be very little leakage (if you built your box well) - leave the pump running for however long it takes the epoxy to get past the gel stage, at least. The kind of pump I show on my web page is what you want, not a lab high vacuum pump - so you can draw the vac to 20 to 25 inches.

--------------------------------------------------
From: "Phillip Slawinski" <pslawinski@xxxxxxxxx>
Sent: Friday, April 09, 2010 5:42 AM
To: "Tesla Coil Mailing List" <tesla@xxxxxxxxxx>
Subject: Re: [TCML] Lacquer

Bill,

I had already contemplated creating something like you describe.  I had
dismissed the idea as being "crazy" because of the cost and effort
involved.  It would be pretty expensive to even accommodate something the
size of the secondary on my small DRSSTC. Imagine if I were to want to use this idea on something like a 12" x 48" secondary. Also the whole box would
have to be made of very thick, and very expensive acrylic (or
polycarbonate), or at least have lots of portholes. Then you have to have a
mechanical system for applying the epoxy, or gloves, further adding to the
cost. Maybe I can convince the folks at Marshall Space Flight center to let
me use one of their vacuum chambers. (Fat chance)  I happen to live very
close to MSFC, and I work even closer.  Sitting at my desk, I'm only about
ten minutes away from some sizable vacuum chambers.

-Phillip Slawinski

Onhu, Apr 8, 2010 at 22:18, Bill Noble <william_b_noble@xxxxxxx> wrote:

yeah, but ---- that wouldn't work - the thing needs to be turning while you apply epoxy, then while it's still turning, seal and draw vac. if you had
high quality rotary vac seal you could get away with motor outside -
sometimes a good sealed ball bearing will do (see the article on vacuum
chucks on my web page for if you are desperate - wbnoble.com) but, if you
can make a box that will handle the (very large) compressive forces, that
would be easiest - remember you will have about 15 psi, and those square
inches add up quickly.

--------------------------------------------------
From: "Yurtle Turtle" <yurtle_t@xxxxxxxxx>
Sent: Thursday, April 08, 2010 2:04 PM

To: "Tesla Coil Mailing List" <tesla@xxxxxxxxxx>
Subject: Re: [TCML] Lacquer

You wouldn't need to have the motor inside the vacuum. A larger pipe with
endcaps and a vacuum fitting could be fitted over the freshly coated
secondary. Both the vacuum pipe and the secondary could share the same
shaft, which could be connected to the motor. Pump it down then spin it up.

Still, a lot of work.

--- On Thu, 4/8/10, Bill Noble <william_b_noble@xxxxxxx> wrote:

 From: Bill Noble <william_b_noble@xxxxxxx>
Subject: Re: [TCML] Lacquer
To: "Tesla Coil Mailing List" <tesla@xxxxxxxxxx>
Date: Thursday, April 8, 2010, 2:20 PM
if it just so happens that you have a
container you can seal that will hold the coil and the
mechanism to rotate it while the epoxy cures, and that it so
happens that you have a vacuum pump, and you use grease with
a low vapor point on the bearings of the motor, then you
could get rid of the bubbles by drawing a vacuum - not a
high vacuum - 20 to 25 inches would be fine

--------------------------------------------------
From: "Phillip Slawinski" <pslawinski@xxxxxxxxx>
Sent: Thursday, April 08, 2010 10:18 AM
To: "Tesla Coil Mailing List" <tesla@xxxxxxxxxx>
Subject: Re: [TCML] Lacquer

> Rob,
>
> Well, it took me a lot of practice to get results like
that (and believe it
> or not, I'm still not entirely satisfied with
it).  I use a plastic spreader
> to apply the epoxy.  On the first few coils I did
I tried using a foam brush
> (that's a BAD idea).  I have a DC gear motor to
spin the form.  I have that
> hooked to a variable DC supply and I can adjust the
speed down to about four
> RPM.  It's important to apply the epoxy at a
slightly higher speed than you
> let it cure at.  This ensures minimal
dripping.  After you ensure that the
> epoxy is spread evenly over the form you can slow the
speed down.  I use a
> heat gun to remove small bubbles from the
finish.  You have to experiment
> with this, because if you heat up one spot too much it
will bubble, or it
> will become so runny that it drips off the form.
One more important note:
> you should do this in a low or preferably no traffic
room.  Be careful not
> to move too quickly and stir up dust.  If dust
lands on the form during the
> initial phase of curing it will make a dimple in the
finish.
>
> -Phillip Slawinski
>
> On Thu, Apr 8, 2010 at 10:43, Rob Byron <mustang_5l87@xxxxxxxxxxx>
wrote:
>
>> Phillip,
>> How do you get your epoxy so crystal clear? I use
a two-part epoxy ( not
>> cheap stuff) and it allways ends up foggy looking
because of microsopic
>> bubbles. I use a 24h cure and have it set up on a
rotating assembly with a
>> microwave turntable motor. Is it how you mix it
that matters? Or how you
>> apply it?  Your coils look amazing by the
way!
>>
>> Rob.
>>
>> ________________________
>>
>> On 2010-04-08 09:33:32 -0600 Phillip Slawinski
<pslawinski@xxxxxxxxx>
>> wrote:
>>
>> >
>> > Hi All,
>> >
>> > I too use the two-part epoxy coating on all
my coils.  I built a coil
>> from
>> > the ground up to produce a long spark length
compared to the secondary
>> > length.  It has taken a lot of work, but
I think the results were worth
>> it.
>> > http://www.flickr.com/photos/pslawinski/4354745760/
During the process
>> of
>> > developing this coil I have had multiple
flash overs.
>> > http://www.flickr.com/photos/pslawinski/4309814799/
I haven't lost a
>> > secondary to a flash over or spark related
event.  My secondary is > wound
>> > with 34 AWG on a 12" x 3.5" form.  Not
coating a form with such fine > wire
>> is
>> > simply not an option.  The wire is very
fragile, and will break with > only
>> a
>> > mild amount of force, also with wire this
fine expansion and > contraction
>> of
>> > the form due to temperature change will cause
the windings to loosen up
>> and
>> > fall down.  Sadly, I know this from
experience.
>> >
>> > -Phillip Slawinski
>> >
>> > On Thu, Apr 8, 2010 at 08:22, Peter Terren
<pterren@xxxxxxxxxxxx>
> wrote:
>> >
>> >> Firstly, the experiment with the
conventional coil is not conclusive,
>> >> sorry.  Power was "about 20%" in the
pre shot with racing sparks. No
>> >> mention
>> >> of actual values for the post shot and
the sparks look very different >> on
>> >> the
>> >> pics.
>> >> I am not saying the result is wrong, but
it is highly likely the
>> original
>> >> power level was not reproduced.
>> >>
>> >> Secondly, DRSSTC's are different beasts
in terms of coupling. >> Obtaining
>> >> better Watt's ratios (spark length/sec
length) seems a lot easier. >> 13:4
>> =
>> >> 3.25 does not seem remarkably efficient
in this regard.
>> >> On the other hand using an SGTC coil with
no special insulation, I >> have
>> >> Watt's ratios of 3.0
(96inches/32in).  Others have claimed larger >>
ratios
>> >> for
>> >> SGTC's but I have not seen clear photos
to show this.  If you want to
>> >> follow
>> >> this link copy and paste it into your
browser.
>> >> http://tesladownunder.com/tesla_coil_sparks.htm#6 inch
coil (the best
>> >> ones)
>> >>
>> >> Nevertheless, the previous discussion of
using ?Envirotex as a very
>> thick
>> >> layer does really seem to provide a lot
of protection.
>> >> Some years ago I started a TC project to
dramatically outperform this
>> 3.0
>> >> Watts number. A lot of special
fabrication was done and I still have
>> >> everything ready to start some final
plans and construction. One day
>> when I
>> >> have a few moments........
>> >>
>> >> Peter
>> >>
>> >>
>> >>
>> >>
>> >> On 8/04/2010 1:16 PM, Dr.Hankenstein
wrote:
>> >>
>> >>> Greetings,
>> >>>
>> >>> If you're not too sure on the effects
of a good coating (or two or
>> >>> three) of varnish; please refer to a
scientific evaluation on the
>> >>> following link:
>> >>>
>> >>> http://www.audiotesla.org/corona%20experiment.htm
>> >>>
>> >>> This should remove all doubt that
varnish does more than just hold >>> the
>> >>> winding in place and end the
hypothetical armchair speculation. Dr.
>> >>> Spark has at least 80 coats of
varnish on "Fatboy"---13+ footers out >>> of
>> >>> a 4 foot secondary proves it:
>> http://www.drspark.org/fatboy1_rebuild.htm
>> >>>
>> >>> Regards,
>> >>> Hank
>> >>>
>>
>>>   _______________________________________________
>> >> Tesla mailing list
>> >> Tesla@xxxxxxxxxx
>> >> http://www.pupman.com/mailman/listinfo/tesla
>> >>
>> >
_______________________________________________
>> > Tesla mailing list
>> > Tesla@xxxxxxxxxx
>> > http://www.pupman.com/mailman/listinfo/tesla
>> >
>>
>> _______________________________________________
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>>
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