The input power was ~260W.  I don't know what the R value of the insulation
is.  I had the cell surrounded by high purity alumina powder and covered
with a thin sheet of ceramic insulation.  I used standard 120V AC 60hz with
a triac type dimmer switch (chops the waves starting at V=0).  I'll have to
check with the manufacturer to see what the remaining 5% of the tube is.
The heating element was Kanthal A1.  It's strange that the heating element
was able to completely melt at points.  In the past, it has always failed
before melting.

I was using INCO type 255 nickel, TiH2, LiOh, KOH, aluminum powder, and
Fe2O3.  Good idea on the small amount of fuel which should cause some
localized melting.

The fact that the fuel was a small diameter cylinder seems to suggest that
it was fully expanded in the tube and shrunk down.


On Tue, Mar 17, 2015 at 2:02 PM, Bob Cook <> wrote:

>  Jack--
> It looks like you had a pretty good reaction.
> What was the input power?  What is the R value of the insulation on the
> outside of the electric coils?  What was the nature of the electrical
> input--frequency etc?  And what is the electrical heating element
> material?   If you have an acetylene torch, see if you can melt a piece of
> the tube that melted.
> The tube may have had glass fibers incorporated in order to improve
> strength.  You indicated it was 95% pure.  What was the other 5%?
> What was you fuel mixture?  You may want to try a small fuel loading and
> see if the same intense reaction happens--all else the same.
> Try the test with a iron core instead of a fuel load and determine if
> there is an apparent magnetic field which would hold the iron core in
> position when direct current is applied to the heating coil.  An
> alternating current would of course change the magnetic field and may
> make for null reaction conditions.
>  Try 2 or 3 t/c's if you can--one inside and two outside to get a measure
> of the temperature gradient along the tube.  Also another easy way to
> determine temperatures is the use of thermal sticks on accessible
> surfaces.  Welders use these to determine preheating temperatures.  They
> may provide a cheap temperature measure for you.
> Keep it shielded--good luck.
> Bob
> ----- Original Message -----
> *From:* Jack Cole <>
> *To:*
> *Sent:* Tuesday, March 17, 2015 9:39 AM
> *Subject:* Re: [Vo]:melted alumina tube
> To add a couple of more details.  The agglomerated piece of material is
> extremely hard.  I tried to break it off with pliers, but it seemed like it
> would take more force than to break the entire cell.  The resistance wire
> is extremely difficult to separate from the cell. I plan to open the cell
> with a diamond blade later today to see if more can be learned about what
> took place (e.g., evidence of melting on the inside of tube).  I was able
> to get one piece of the resistance wire pried from the tube.  There were
> indentations in the cell.
> As a follow-up experiment, I need to run it without the fuel to the same
> power levels to see if the same effects occur.
> On Tue, Mar 17, 2015 at 9:42 AM, Jack Cole <> wrote:
>>  I had an interesting experiment yesterday.  This was my first time
>> using a triac to regulate input power and sealing the tube with a
>> compression fitting.  Unfortunately, my thermocouple failed.
>> Take a look at the alumina tube and the evidence for melting.  The
>> furnace sealant which I coated it with completely melted and agglomerated
>> to the bottom of the cell (also appears to be mixed with melted alumina).
>> The tube was purchased from China and is purportedly 95% pure.  It was
>> supposed to have a continuous operating temperature of 1500C.
>> Any opinions?
>> Jack

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