William & Susan Schran User on mon 20 feb 06
On 2/19/06 9:01 PM, "C. A. Sanger" wrote:
> My problem is now the government has forced changes in the tanks, reducing the
> pressure, supposedly to make them safer. I can't even get them to refill my
> tank--they say I have to pay a small fee and they will replace my tank with
> one of the new ones with the reduced flow pressure. This reduced pressure
> simply won't work with my burner setup, there is not enough gas pressure.
Hmmm... Reduced pressure.
I thought the new valve assembly had to do with not over-filling the tank.
I had the valve replaced on one of our older 20# tanks and never noticed any
change in pressure, worked at the same (according to the pressure gauge)
pressure as before the conversion.
I've since switched to 30# tanks - less trips to get refills.
How much pressure are you using? Have you tried less pressure and cutting
back on the air flow?
We use a simple venturi burner and never go over 2 lbs. to fire in 15
minutes.
-- William "Bill" Schran
Fredericksburg, Virginia
wschran@cox.net
wschran@nvcc.edu
Snail Scott on mon 20 feb 06
At 02:01 AM 2/20/2006 GMT, you wrote:
>...My problem is now the government has forced changes in the tanks,
reducing the pressure, supposedly to make them safer...Does anyone know any
way I can refit my setup to increase the pressure?
If you want more pressure, gang two tanks together
with a manifold. This will also reduce pressure-drop
freeze problems associated with drawing from a small
tank.
You _will_ need to get the new overfill-prevention
valve (OPV) style tanks, though. Unless you've got
an inside track with someone (asking them to do
something illegal), you can't get the old ones
refilled anymore.
I've never found that the new valves affect pressure,
though I admit I don't generally run my tanks
'full-bore'.
-Snail
Craig Clark on mon 20 feb 06
C.A., I'm not sure what your gas supplier was referencing but I=20
recently had 2 old 100 lb tanks checked and refilled. They were given to =
me by anothe potter who no longer needed them. I had to replace the=20
valve stem on one of them. They were both recertified. So check and ask=20
them about the specifics of the reference. Sounds a little odd to me.
As to the pressure requirements, what type of pressure do you need?=20
I have always been able to fire to raku temps with a the regulated=20
pressure set on a coupla pounds. Even if there is a new regulation=20
regarding the amount of pressure in a tank, which I don't understand=20
when I think of the liquid nature of propane that is used to fill the=20
tanks, there will be enough pressure under normal operating conditions=20
to fire a small burner. The problem is with volume, not pressure. In=20
order to fire a much larger kiln you will need to manifold several tanks =
together to keep the volume up enough to prevent freeze out.
One thing to think about is that when you are firing something as=20
small as a small trash can is that you don't need any type of forced=20
draft. This only reason for forced draft is to get hot really, really,=20
really fast. There is no reason for this. It is hard on the ware. Many=20
folks fire with nice easy going thirty minute cycles. Not to mention the =
fact that those blowers just make a whole bunch of racket.
I'm glad to read that you did not take the advice to use clear=20
plastic tubeing. This would be playing fast and loose with the safety=20
margin and I always consider it to be penny wise and pound foolish to=20
get into that game. Please tell me that someone who promotes themselves=20
as a professional did not recomment that you do use clear plastic=20
tubing?!?!?!?!? I mean, it can be done, is done, but it certainly is not =
safe.
If you want some outstanding advice give Marc Ward, of Ward Burner=20
Systems, a call. He is one of the best in the business by a long shot=20
and has readily answered all questions that I have had over the years.=20
He won't charge you anything to answer your questions though he may try=20
and sell you a burner. His number is (832)397-2914....here's the=20
link...http://www.wardburner.com/venturi_raku.cfm
Alternatively you can just call me, and though I not a certified=20
expert I may be able to answer any question which you may have. I always =
try and help out those who are getting into Raku. It was, and remains,=20
my first love in clay.
Hope this helps
Craig Dunn Clark
619 East 11 1/2 St
Houston, Texas 77008
(713)861-2083
mudman@hal-pc.org
C. A. Sanger wrote:
>Hi! I have a portable raku made by the plans in Colson's Space Age Mate=
rials, where a small trash can is lined with fiber. The burner was home =
constructed and air power supplied by a handheld (old) vacuam cleaner. G=
as is from a small tank similar to those on recreational vehicles. I pai=
d a professional to rig the supply line with guages and safety devices an=
d cutoff valves--no "clear plastic tubing" on the setup like called for i=
n the original plans. My problem is now the government has forced change=
s in the tanks, reducing the pressure, supposedly to make them safer. I =
can't even get them to refill my tank--they say I have to pay a small fee=
and they will replace my tank with one of the new ones with the reduced =
flow pressure. This reduced pressure simply won't work with my burner se=
tup, there is not enough gas pressure. Does anyone know any way I can re=
fit my setup to increase the pressure? Thanks! =20
>
>C. A. Sanger ShardRock Clay Studio Herington, KS 67449
>
>________________________________________________________________________=
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>
> =20
>
C. A. Sanger on mon 20 feb 06
Hi! I have a portable raku made by the plans in Colson's Space Age Mater=
ials, where a small trash can is lined with fiber. The burner was home c=
onstructed and air power supplied by a handheld (old) vacuam cleaner. Ga=
s is from a small tank similar to those on recreational vehicles. I paid=
a professional to rig the supply line with guages and safety devices and=
cutoff valves--no "clear plastic tubing" on the setup like called for in=
the original plans. My problem is now the government has forced changes=
in the tanks, reducing the pressure, supposedly to make them safer. I c=
an't even get them to refill my tank--they say I have to pay a small fee =
and they will replace my tank with one of the new ones with the reduced f=
low pressure. This reduced pressure simply won't work with my burner set=
up, there is not enough gas pressure. Does anyone know any way I can ref=
it my setup to increase the pressure? Thanks! =20
C. A. Sanger ShardRock Clay Studio Herington, KS 67449
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