Hello Gentlemen,

I've been listening to the conversations about the capacitor explosion.
I felt I must address this issue before Condenser Products discontinues
making these caps because of this issue.

--Stepping onto the soapbox--

First, a reminder.  Tesla Coiling is a VERY DANGEROUS HOBBY.  How easy that
is to forget.  You only get one mistake while coiling.  After that, you're
worm food.  Sorry for being so coarse, but it is a fact that we must accept
as Telsa coil hobbyists.

In order to practice this hobby safely, industrial safety precautions should
be utilized.  This includes safety shields and lock-out procedures.  Safety
shields should be installed around the capacitor(s) and rotary wheel, at a bare
minimum.  There is stored energy in both of these devices (one electrical, one
mechanical) and as such, have the some potential for explosion.  I for one do
not assume that the caps that I use are completely "bulletproof".  Any component
can fail.  Remember, the component that takes the most abuse in a tesla tank
circuit is the capacitor.  Lock-out procedures should be used at the power
panel.  Do not just throw the switch off and walk up to a high powered coil.
Use a padlock to lock-out the disconnect.  Keep only one key and give no one
else a key.  If there are several people in the area coiling with you, use a
multiple hasp for the lock-out.  Every one should have their own lock with a
single key.

If we do not take responsibility for our own actions or inactions, someone
eventually will.  This is usually in the form of the goverment.  It is
plausable that telsa coiling could be made illegal.  After all, it is a
hobby fraught with liability issues.  If we begin to blame others for our
injuries, we risk this very thing happening.

I have been working with electronic components for years.  Things blow up, even
new components.  Safety must always be considered.  When you are looking at small
amplifier boards or the similar, you only let out the magic smoke.  When you are
talking about capacitors that can hold many Joules of energy, a failure can be
explosive.  A safety shield or cage should always be used around a pulse cap in
a Tesla coil system.

Now I would like to address the situation with Condenser Products.

When I placed that first order with Condenser Products, oh so long ago, it was
after considerable research.  I spent many hours on the phone with Condenser
Products, NWL and Plastic Capacitors.  I talk extensively with their engineers
(not salespeople) about capciotrs used for our applications.  It became quite
clear to me that capacitors must be severely derated in Tesla tank circuit.
(This statement is by now "old news"  to all)  Without going into all of the
details I discussed with them at that time (resonant rise, pulse rates, resonant
frequency range, etc. ad neauseum), I found that there was no real hard answer
as to what will survive in a Tesla tank circuit.  All of these companies rely
on calculations, but then fall back to their past experience.  All of these
companies provide caps to all in the Tesla coil business.

NWL - Use be Richard Hull.

Plastic Capacitors - Used by D C Cox.

Condenser Products - Used by Bill Wingate.

(I can't recall who Bill Wysock uses.)

Of the companies, Plastic Capacitors is the least responsive.  Their product seems
good and their engineers competent, but they price themselves out of it.  They use
a rectangular, horizontal mount, top lug design case.  They seemed a bit anemic when I
talked about warranty.

NWL is the most responsive company.  All of the units they make are to customer specs.
They build to order.  They are hungry for business.  They seemed very interested.  NWL
was also very positive about warranty.  They use PP cases on their caps, not PVC.
Their caps use a recangular, vertically mounted, top lug case with feet.  Their
prices were about 25%-50% higher than Condenser Products, but it is an excellent
design worth consideration if you don't mind the extra cost.

Condenser Products seemed the best mix of quality vs cost.  They offer a faily complete
range of "standard" Tesla caps.  Their warrantee practices seem fair.  Any custom
voltage/capacitances would be quite expensive.  Their cases are a round, horizontal
mount, end lug design.  Their prices are the best by quite a margin.  A comparable cap
to the .025 -at- 20 KV unit that we got originally would have cost over $300 each from NWL.
It was astronomical from Plastic Capacitors.

--stepping off the soapbox--

In light of the beating that CP has been taking, I decided to call them and discuss the
matter.  I spent a half hour or so on the phone this morning with Bill Mason, president
of Condensor Products.  I learned some interesting facts.

First, it is apparently important that if these caps are to be stored for more than 6
months that they be periodically rotated.  If they are in service, this is not necessary.
The usage of the cap keeps the oil moving and between the plates.  This is apparently the
mode of Richard Wall's failure.  I have pounded on one of my caps with 17 KV AC RMS and
it doesn't even get warm after a 10 minute run.  I have never rotated them, but I do fire
them at least every couple of weeks or so.

CP will replace Richard Wall's cap, if it failed this way.  It is just a matter of
returning it to them.

Bill wasn't familiar with Ed's situation.  Jeff Fielder is on vacation this week so I
couldn't talk to him about that.

Now, the issue of explosion/liability/pressure vent.

The addition of a pressure vent is not a viable option.  This would add cost, tremendous
cost.  It also give moisture a point to seep in as the capacitor warms and cools.  A weak
point in the case is also something that would add great cost and not be reliable.

These explosions of Ed's and Richard's is of great concern to Bill Mason.  From Bill's
standpoint, this is a liability can of worms.  He has offered these caps for years to
coilers.  Ed Wingate has many of them over the years.  None of them have failed, as far
as Bill knows.  Now Richard Wall has asked them who was going to pay his doctor bills.
Therefore, CP was forced to contact its attorney and insurance carrier.  The insurance
carrier then contacted Richard Wall.  In light of this accident, Bill Mason contacted
his attorney to have him review the liability issue of offering these caps.  Now that
hobbyists are using them extensively, he fear that someone will hurst themselves if
they accidentally mis-apply their product.  He was more confident in making this product
when only engineers were buying them who he felt understood the dangers present.  However,
Bill does claim that these are the first instances of their Telsa coil caps exploding.

Now, CP is seriously considering discontinuing offering these caps.  This will depend on
what their attorney advises them.  That means that we will all be forced to pay higher
prices for capacitors from other companies.  Let us all hope that Condenser Products
does not discontinue these caps.  I for one feel quite confident using their product.
Even if I do have one fail eventually, I will still continue to buy their caps.  If I
do need a custom, I will turn to NWL, and pay the higher prices for it.  I hope I can
continue to make use of the standard product now offered by CP.

This may have a grave affect on the now pending order.  I will talk to them further as this
situation develops.

I am not taking sides here.  I just don't want to lose CP as a source for capacitors.  While
this is a bad situation and I don't envy Richard or Ed, I think it is important to keep
in mind that these are only two instances.  I have heard much more good about CP than bad.
As a matter of fact, these are the first I have heard of bad news about their caps.  It might
be good to contact Ed Wingate ansd ask his opinion before continuing.  I think I may have
to do exacly that.

Scott Myers