Re: Tesla Coil Firehazards (Exploding paint cans) (fwd)

["Tesla list" <tesla@xxxxxxxxxx>]

---------- Forwarded message ----------
Date: Sat, 11 Aug 2007 17:01:29 -0700
From: Nathan Stokely <50kva.54uf.750a@xxxxxxxxx>
To: Tesla list <tesla@xxxxxxxxxx>
Subject: Re: Tesla Coil Firehazards (Exploding paint cans) (fwd)

This accident can and does happen. I have only encountered this twice and
only with cans that are nearly empty. Because there is less matter to heat,
the streamers can heat the can very quickly. Concrete provides an excellent
ground reference, so, a can of spray paint on concrete is grounded. Because
of this, streamers can be continuously heating the can. (I often run the
coil for extended periods of time and sometimes without supervision which,
is an unsafe practice, however, I do not have much time to devote to these
things.) When the contents of a can heat, they expand and this thermal
expansion can rupture the can causing a rapid release of pressure which
expels the hydrocarbon propellant and the paint out of the can. The mixture
of paint and propellant burns very energetically and can catch other things
on fire. For proof, some cans of aerosol have a warning which states "Do not
expose to electrical current. May cause flash fire." The reason it has
happened multiple times is because the only place I have to do this is in my
garage which is used to have many cans of spray paint on the concrete from
my friends skateboard making. If you don't believe me, I can't help it.

On 8/11/07, Tesla list <tesla@xxxxxxxxxx> wrote:
>
>
> ---------- Forwarded message ----------
> Date: Sat, 11 Aug 2007 09:32:22 +0800
> From: Peter Terren <pterren@xxxxxxxxxxxx>
> To: Tesla list <tesla@xxxxxxxxxx>
> Subject: Re: Tesla Coil Firehazards (Exploding paint cans)
>
> I'll call your bluff on this one and say that you made this one up.
> You say you have encountered explosions with paint "most often".
> Two reasons I find it hard to believe you.
> A can is almost a full Faraday cage and it is hard to imagine how a strike
> could give a spark inside a can.  The contents are probably not flammable
> themselves (hydrocarbon propellant and paint) until mixed with air.
> Striking the outside of a can results in very little heat transfer. Try
> heating a full coke can and you will be very disappointed.
> So as you started this, please give details of :
> 1 Exactly how many explosions you have had?
> 2 What were your TC details including power?
> 3 Was it just streamers that ignited the cans as you say, not direct
> sparks?
> 4 Did the cans have caps on them?
> 5 Why didn't you stop having the TC strike the cans after the first flash
> fire?
> 6  If no-one on this list can reproduce your findings and we believe that
> you have lied, what should the group response be?
>
> Peter
> http://tesladownunder.com
>
> > ---------- Forwarded message ----------
> > Date: Fri, 10 Aug 2007 10:15:58 -0700
> > From: Nathan Stokely <50kva.54uf.750a@xxxxxxxxx>
> > To: Tesla list <tesla@xxxxxxxxxx>
> > Subject: Re: Tesla Coil Firehazards (fwd)
> >
> > Paper and wood are the least of your worries. Any flammable/explosive
> > vapours such as petrol or methane can ignite very easily from the
> > streamers.
> > Also, strikes to aerosol containers (such as bug spray, spray paint, or
> > anything else you have where you operate your coil) can cause the
> > hydrocarbon fuel in the aerosol to rapidly expand bursting the can and
> > causing a flash fire. I have encountered this with spray paint the most
> > often. The can will explode and then the paint (which burns hot) flies
> > everywhere and can catch your garage on fire. Always stay away from
> > aerosols
> > and fuels while operating a coil.
> >
> > On 8/9/07, Tesla list <tesla@xxxxxxxxxx> wrote:
>
>
>
>