koratpot@korat.loxinfo.co.th on mon 7 apr 97
**************Original message*************
> From: Sylvia See
> I find my 100 lb bottles of propane frost up on me if I use too much
> pressure to fire it too fast<
****************************
This problem can be solved by heating the bottle. If propane use is
moderate, simply setting the bottle in a tank of water helps a lot.
The liquid propane needs heat to vaporize, and it can get heat out of
water a lot more easily than out of air.
But if you want to use a lot of propane fast, heating the water is
the answer. I use the bottom 3rd of a 200 liter (55 gal US, 50 gal
Imp) oil drum, with 3 steel pipe legs welded on, and a burner from a
cookstove under it. This solves the problem--can go through a bottle
of gas fast, with good pressure.
There is a possibility of overheating the water and exploding the
bottle, of course. I watch the pressure gauge before the regulator,
the one which registers pressure in the tank. Up to 100 psi is safe,
they tell me. I've never personally seen it go above a hundred, tho
I've heard tales.
Another danger point is at the end of the firing, when the water's
hot and you turn off the gas. I have dipped out the hot water and
replaced it with cold at this point. Safety first.
Good luck,
Nikom
koratpot@korat.loxinfo.co.th
Sylvia See on mon 7 apr 97
Hi Nikom;
Wow that's kind of a scarry proposition you have suggested. Think I'll
settle for a little longer firing. I have used a hair blower and that
worked pretty well, but even then I kept it off the high heat. I have fired
in the winter using the hair blower and wrapped the bottles with
insulation. I have them sitting in an open fronted box, and even hanging
the blower into the box and partially enclosing it seemed to work better
than sitting in the cold holding the blower. It seems that the warm air
helps, but to be honest, I would be a little afraid of a burner under hot
water at this point.
Thanks for the suggestion though and I may work on altering it abit.
Sylvia See Claresholm, Alberta sylviac@telusplanet.net
I really like my bifocals
My dentures fit me fine
My hearing aid works perfect
But Lord I miss my mind!!!!
Lauren BAll on mon 7 apr 97
koratpot@korat.loxinfo.co.th wrote:
>
> ----------------------------Original message----------------------------
>
> **************Original message*************
> > From: Sylvia See
> > I find my 100 lb bottles of propane frost up on me if I use too much
> > pressure to fire it too fast<
> ****************************
> This problem can be solved by heating the bottle. If propane use is
> moderate, simply setting the bottle in a tank of water helps a lot.
> The liquid propane needs heat to vaporize, and it can get heat out of
> water a lot more easily than out of air.
> But if you want to use a lot of propane fast, heating the water is
> the answer. I use the bottom 3rd of a 200 liter (55 gal US, 50 gal
> Imp) oil drum, with 3 steel pipe legs welded on, and a burner from a
> cookstove under it. This solves the problem--can go through a bottle
> of gas fast, with good pressure.
> There is a possibility of overheating the water and exploding the
> bottle, of course. I watch the pressure gauge before the regulator,
> the one which registers pressure in the tank. Up to 100 psi is safe,
> they tell me. I've never personally seen it go above a hundred, tho
> I've heard tales.
> Another danger point is at the end of the firing, when the water's
> hot and you turn off the gas. I have dipped out the hot water and
> replaced it with cold at this point. Safety first.
> Good luck,
> Nikom
> koratpot@korat.loxinfo.co.th
This is one of the most dangerous stunts I've heard about. Even the
tiniest propane leak will be ignited by the burner. If the tank were or
any seams of fittings rupture with a burner that close is a big bomb
waiting to kill. A small 5 gallon tank of propane if ignited can burn a
two story house down in less than 3 minutes. If it explodes it can
throw shrapnel several hundred yards. Find a safer way to heat the
water, or use a bigger tank. But please stop this practice.
Lauren
Kenneth D Westfall on tue 8 apr 97
I will hope only someone with a death wish will use a heated hot water
bath to increase the pressure on a propane tank. The pressure can change
to fast for someone to react and maintain a safe pressure. A far safer
method is to use multiple tanks connected together or get a larger single
tank 250 gal tank or a 500 gal tank.
Kenneth Westfall
Pine Hill Pottery
potter-ken@juno.com
Daphne Zeitz on tue 8 apr 97
When my propane slows down I just tie the end of the garden hose to the top
of the bottle and let water drizzle down the outside of the bottle. If you
need it warmer, perhaps you have a laundry tub faucet that you could run
warm water through.
Good luck,
Daphne
JULIE ATWOOD on tue 8 apr 97
I have found that simply pouring warm to hot water over the tank and down
the sides is all that is neccessary to warm the propane tank. NO BURNERS
near the tank!! Keep a bucket of hot water near the tank and
periodically pour it over the tank.
Julie in Seattle
> This is one of the most dangerous stunts I've heard about. Even the
> tiniest propane leak will be ignited by the burner. If the tank were or
> any seams of fittings rupture with a burner that close is a big bomb
> waiting to kill. A small 5 gallon tank of propane if ignited can burn a
> two story house down in less than 3 minutes. If it explodes it can
> throw shrapnel several hundred yards. Find a safer way to heat the
> water, or use a bigger tank. But please stop this practice.
> Lauren
>
Richard mahaffey on tue 8 apr 97
The freezing comes from the liquid propane evaporating. I have been told
that one of the critical factors is the surface area. In Japan they use
propane extensively to fire the gas kilns. They usually use several
bottles hooked to a manifold with a pressure regulator. I have fired to
cone 8 in three hours ( they thought it was too fast too!) with no
porblem. The tanks were the size of our 100 lb bottles with about 8
manifolded together. This seemed to give sufficient surface area for
evaproation of the propane. The surface area stays constant so there iis
no problem with the surface area changing, and therefor no troubles with
freezing at the last quarter of the tank volume.b I plan tootry this
system on my next gas kiln.
Rick Mahaffey, Tacoma Community Colege, Tacoma, WA, USA
206-566-5260
Ric Swenson on wed 9 apr 97
>----------------------------Original message----------------------------
>I will hope only someone with a death wish will use a heated hot water
>bath to increase the pressure on a propane tank. The pressure can change
>to fast for someone to react and maintain a safe pressure. A far safer
>method is to use multiple tanks connected together or get a larger single
>tank 250 gal tank or a 500 gal tank.
>
>Kenneth Westfall
>Pine Hill Pottery
>potter-ken@juno.com
---------reply-------------------- to the propane in cold weather syndrome.
IMHO it might be a good idea to ask the people that you get your propane
from what THEY suggest...you are paying them for the gas....they will give
you advice also....Not all of them are "rocket scientists" ( I have
learned), but there are things called VAPORIZORS that are used by people
with large volume kilns, furnaces, etc. Your LPG dealer can tell you about
ways to keep the gas coming when the cones are almost down, the tank is
only half full... and the temperature just hit -20.
Liquified Petroleum Gas burns in kilns....as a vapor not a liquid. So it
must be warm enough to vaporize the liquid...the tank must be full enough
to provide enough pressure to help vaporize the liquid and the line to the
kiln can't be 400 yards (he said "tongue deep in cheek").
An underground tank...a tank in tandem with others to provide the needed
pressure are all good ideas.
Vaporizers are scarey looking things, but they work very well.
I advise everyone to put gas tanks a decent distance from home and studio.
RESPECT anything that burns the way propane does. Remember that it HEAVIER
than air and can sit in low spots...cellars and such ....and wait for you
to drop a cigarette butt, match or turn on a light switch.
Wishing that we had NATURAL gas, (which is lighter than air, generally
cheaper, where available and better in some other ways I think.)
I remain yours truly,
Ric Swenson, Bennington, Vermont ( formerly of Anchorage)
Harvey Sadow on wed 9 apr 97
JULIE ATWOOD wrote:
>
> ----------------------------Original message----------------------------
> I have found that simply pouring warm to hot water over the tank and down
> the sides is all that is neccessary to warm the propane tank.
Frankly, just running cold water over the surface of the tank will keep
it from freezing and maintain the pressure. Turn on the hose to barely
more than a trickle and fire away. Alternatively, switch to a liquid
withdrawal tank and a liquid vaporizing burner and fire away at warp
speed.
Have fun,
Harvey Sadow
koratpot@korat.loxinfo.co.th on wed 9 apr 97
********ORIGINAL MESSAGE***********
> I will hope only someone with a death wish will use a heated hot water
> bath to increase the pressure on a propane tank.
> Kenneth Westfall
******************
I agree that the practice seems
dangerous--I thought so too, first time I saw it.
But at the Thai pottery center of Lampang, with 200-odd companies and
10,000 people employed, everybody heats propane bottles with gas
fires under a water tank, and nobody has any problems. They typically
use 3 tanks in manifold for a 90-180 cubic foot car kiln, cone 7. I've now been
doing it for years, and never a problem.
Heating a gas tank is not inherently unsafe. Waiting for a warm day
to fire is a way of heating a tank, but no one thinks that's unsafe.
In the Great White American North, propane tanks must be heated,
because it gets colder than 40 below, and that is the temperature at
which propane won't vaporize. There, even big tanks are often
insulated and heated with battery blankets or contact-type oil pan
heaters. It isn't dangerous--the tank never reaches the temperature
it would reach on a summer day.
When heating a tank, the only problem is knowing when to stop. It's
good to have a pressure gauge showing pressure in the tank--a gauge
on the tank side of the regulator. Your hand makes a good heat
sensor--the tank should not get hotter than it would sitting in the
sun. A full tank doesn't need heating at all; an almost empty tank
needs lots of heat to raise the pressure. The problem is that the
tanks are full at the beginning of the firing, when you need little
pressure, and getting empty at the end, when you need more.
A Tokenome artist came to stay with me for a month, and told me in
Japan they use vaporizers--an electrically heated box with coils
inside to raise the pressure of the gas. That sounds safer than the
Thai method. But he used our system and called it "Thai vaporizer".
Cheap and works good.
Safety is relative. Safest is not to mess with gas at all. Safest
is not to ride in automobiles, not to drink water, not to be born.
I wouldn't recommend that elementary school students heat gas tanks;
nor elementary school teachers. If you're stupid, inattentive, and
rich, get a 500 gallon tank to fire your little toy kiln. That's safe
for sure. But if you're hip and have a limited budget, you can heat
gas tanks to great advantage.
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