RE:Tincanium Boiling test

["Crispin" <crispin@newdawn.sz>]

Dear Stovers and Ken

>Congratulations on your fabulous results!!

Thanks. I am getting better building the fire.  I am no where near the limit
yet.  I have not yet modified thes tove to provide better heat transfer.  I
think I can double the heat pickup (to 8%?).

>Enjoy your Reign to its fullest while you can.... I haven't built my stove
yet. :-)

I am going to get knocked off my throne in a few days by my own staff.  They
are getting into this.

>Do you perhaps mean 125 x 195 mm?

Yes.

>Do you have the 1.36 litre cans is Swaziland, 106 mm
>dia x 177 mm height? If not, what is the closest you can
>get to this size?

We realized that we can go to the cannery in Malkerns and find out what they
put the juice in.  People here do not buy local juice.  It is all exported.

>What do you presently guess is the practical minimum weight of fuel
>you could use to get your pot boiling in less than a minute?

Presently 120 gms, in future it is probably about 60 grams.  I wil have to
increase the heat pickup. The tin accelerates the process very quickly
because it is SO thin.  I didn't calculate the heat transfer rate yet - too
busy.  Using a black tin (second test) is going to be better than a shiny
one.

I am burning 100 gm/min and it has to be able to go that distance.  Getting
it under 120 gm is difficult. It is burned out in about 80 seconds!  What
was remarkable today was the pickup in heat in the first 30 seconds, which
took 2 minutes a couple of days ago because of hte weather conditions.
There is such a thing as a 'good day for a f'ire.'

>...a piece of aluminum foil, make the holes in it (10 mm
>center hole for penny, and 3 mm vent hole) and
>stretch it over the top of the can. Then hold it in place
>with a few turns of stovepipe wire.

I a going to try to weld a cover on.

>The 10 mm center hole could be cut with a razor blade,

I have the luxury of a hand-held plasma cutter!

>In Canada, our pennies are copper,...

Our ten cents is 21mm in dia but the coins are not round (hard to believe)
and the two cents is square.  The edges are wavy.

>Can you make a little door on the side of your stack...

I can see it from the top.  I just look into the paint cans.  Yes, it is
hot.

>The 3 mm vent hole is very important to allow air and "hiss" to vent,
>to prevent indications of a "false boil."

This must be assessed.  Sorry to confuse things without a proper can. It
will boil faster with a cover too.

>Breathing hard doesn't count. :-)

OK.  I think 90 seonds should be sought for decent steam but one said the
penny moves very easily.

>Were there any indications of "thumping" because of nuclate
>boilng that may tend to shake the pot, and move the penny
>before full boiling occured?

No.  It wasn't a real boil, it was bubbling at the edges with steam.  The
sides and centre bottom get very very hot early, and that is with a 125mm
dia can in a 278mm space so the conduction to the can is terrible.

>Again, my congratulations on your remarkable achievement.

I want to make sure we are doing things properly and that useful knowledge
comes out.
1.    Stack height is going to have to be limited in a competition, perhaps
a measure from the bottom of the fire basket/grate to the top of the
chimney, and perhaps 'classes' with "open" and "limited" and "Formula 1"
etc.

2.    The fire has to be carefully designed.  There is real operator skill
here.  I got a full 25KW within 30 seconds this afternoon.  It is remarkable
to see and hear!  It roars.

3.    The container is very important to the test.  If the cans are not
identical the results are going to be misleading.  I want to be able to
build the stove to run the gasses next to the can which I can't do in the
present one.  I will make a shroud which should increase the heat pickup and
the efficiency.

4.    We have to ban 'trick' cans with interior cavities that displace the
water up against the sides.  I could significantly increase the absorption
by spreading out the water up the side.  The volume is not a good shape for
pickup.  Too much like a cube.

5.    If there is not pretty good secondary combustion, you have NO chance
of getting into this contest.  We should all learn how to get adequate air
in.  I suspect my fire is starved of secondary air at full load.  There is
snakey smoke trailing up from the fire.

6.    If I can continue to divide the pine into (ultimately) shavings, I can
continue to get a faster fire until I have powder that won't burn.  A
reflective grate REALLY helps the initial heating phase along.

7.    This is a great thing to promote in high schools and matel work
classes.  It is real, it is appropriately dangerous, it requires proper
instrumentation and detailed experimental recording, it will teach
discipline and may well lead to people taking pride in some of the simple
things of life.

Thanks to everyone for the encouragement.

Love you guys and girls!
Crispin


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