Craig Martell on fri 8 aug 03
Several years ago there was an article in Pottery in Australia about a salt
kiln that had a stack diverter to nullify any gasses from the kiln. If I
remember correctly, Max Murray, the guy who marketed AIC Oxyprobes was one
or the brains behind this.
The kiln had a stainless steel diverter stack with a shower head
installed. When salt was introduced into the firebox and gasses were
emitted the main stack would be closed off with a top mounted shutter and
the gasses would divert into the stainless stack. The water from the
shower head would convert the chlorine gas into a very dilute solution of
hydrochloric acid. This would run out the bottom of the diverter stack
thru a pipe that went to a barrel of lime chips that would neutralize the
hyrochloric acid. They tested the runoff with litmus paper and, as I
remember, it worked well.
regards, Craig Martell Hopewell, Oregon
Norm Hendry on fri 8 aug 03
Is there a way to "scavenge" off the smoke and vapors coming out the flue in a salt firing? I do have a hood with a 3 foot stack on it and could fabricate or add something to it to cut down or eliminate the smoke-it is concerning my neighbors! Also, I currently salt with moistened rock salt, added in the fireboxes in piles off a piece of angle iron. I dump in 7 pounds from cone 9 to cone 10 in a little 6 cubic foot Alpine. In 1967, they offered a "Salt" model complete with ports and high-alumina bricks for $200 extra-I converted mine with ITC coatings and a Sawzall. Any other suggestions, with the goal being to continue the great salt effects on the pots without producing the fire-terrified effects on my friends and neighbors. Thanks a bunch. Norm
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John Baymore on sat 9 aug 03
Is there a way to "scavenge" off the smoke and vapors coming out the flue=
in a salt firing? I do have a hood with a 3 foot stack on it and could
fabricate or add something to it to cut down or eliminate the smoke-it is=
concerning my neighbors! =
I can possibly give you a contact (off list cause I don't have permission=
to post this info publically) that may be able to help you with some idea=
It relates to a salt glazing potter that got really nailed by the EPA du=
to neighbor complaints and had to either scrub it or shut it comnpletely
down. This system designed is to meet EPA regs....... and they still
monitor the site regularly....... and it wasn't cheap to put in and it
isn't cheap to maintain it. Industrial type bag house system with
chemical lime treatment. =
In far less stringent situtations starting back at Massart in the early
70's, I have built units for the top of the chimney that utilized a fine
water mist sprayed thru the effluent and then the water is caught and
disposed of. There is still some steam present.... but it cuts the "grou=
hugging and long sustaining salt mist". Wouldn't pass EPA type
scruitiny.... too low tech........ but might work for your needs. Cobbl=
up a temporary test scenario......... and then if it works adequately
........make a permanent unit. The water spray mist should be as fine as=
you can create without going nuts. All the metal in the effluent stream
and carrying the water post flue area has to be out of stainless.......
corrodes in an instant if not . Ditto the spray nozzles if you really=
get them into the effluent stream. So it is not a really cheap thing to
do. The test unit can be mild steel....it's not meant to last. The
contaminated water needs to be disposed of .....which is a separate isse.=
The higher the water flow... the less the water chemistry is
affected....... so you don't get into high concentrations of the effluent=
materials in the water. =
But then you generate a lot of waste water. You could recycle the
water.... but that would involve treating it chemically and continually
monitoring stuff like the PH and having a corrosion proof pump and so on.=
My suggestion is keep it simple unless someone MAKES you make it
So... hopefully a thought. =
PS: The neighbors............ give em' pots! Lots of pots .
River Bend Pottery
22 Riverbend Way
Wilton, NH 03086-5812 USA
"Earth, Water, and Fire Noborigama Woodfiring Workshop: August 15-24,
Leonard Smith on sun 10 aug 03
On Saturday, August 9, 2003, at 01:18 PM, Craig Martell wrote:
> Several years ago there was an article in Pottery in Australia about a
> kiln that had a stack diverter to nullify any gasses from the kiln.
> If I
> remember correctly, Max Murray, the guy who marketed AIC Oxyprobes was
> or the brains behind this.
> The kiln had a stainless steel diverter stack with a shower head
> installed. When salt was introduced into the firebox and gasses were
> emitted the main stack would be closed off with a top mounted shutter
> the gasses would divert into the stainless stack. The water from the
> shower head would convert the chlorine gas into a very dilute solution
> hydrochloric acid. This would run out the bottom of the diverter stack
> thru a pipe that went to a barrel of lime chips that would neutralize
> hyrochloric acid. They tested the runoff with litmus paper and, as I
> remember, it worked well.
From memory it was a Steve Harrison design. If not then Steve designed
and built just such a device for Janet Mansfield so that she could
legally fire her salt kiln in the centre of Sydney. Steve may have more
to say about it.
Rosedale St Gallery
2A Rosedale Street
Dulwich Hill NSW 2203
steve harrison on sun 10 aug 03
> Is there a way to "scavenge" off the smoke and vapors coming out the
> flue in a salt firing?
> Thanks a bunch. Norm
> Hi Norm,
yes there is a way to reduce the salt vapours from your kiln flue.
I've built a few of them. I can't say that i know the best way, but
I've done three and they have worked.
The idea is to put a stainless steel flue on top of the kiln chimney.
this is sealed at the bottom with a stainless steel plate with a hole
cut in the size of the flue a ring welded in, in such a way that the
the flue gasses can enter and pass up the pipe, but it will hold water.
Water is sprayed down this flue extension from a spray nozzle. It is
very important that the water droplets are the right size. If they are
too fine, the heat from the flue gasses evaporates the water into steam
and it all goes up the chimney. If they are too large, there will not
be enough surface area too dissolve the gasses. it is also important
that the nozzle is also made from stainless, so that ti won't rust away
with the salt attack at high temps.
I read an article about this sort of thing in New Scientist magazine
quite some years back, regarding the removal of smoke from burning Jet
passenger plans. Apparently more people die in aeroplane fires from
the smoke inhalation of burning toxic plastic fumes etc from the seats
and lining. So a lot of research was put into the droplet shape, size
and distribution to wash the smoke particles from the air. The same
kind of research needs to be done on the interior of the salt scrubber.
The closest thing that is affordable to potters that I could find is a
stainless steel agricultural spray jet from Canada called a whorl jet
spray nozzle. I used 1.2 mm. dia. This puts out a hollow cone of medium
sized droplets which are aimed down the flue. The salt fumes are washed
out of the flue gasses and the chimney emissions are fairly clear.
I went for multiple redundancy, 3 or 4 sprays, one above the other at
500 mm. spacings.
Turn on the water when the kiln gets too 1000oC or when white salt
vapour starts to appear at the chimney, keep the water running to keep
the spray jets cool right to the end of the firing and a couple of
hours into the cooling.
Adjust the water pressure to find the best spray pattern for efficient
The water is collected in the bottom of the scrubber, and drained off
through a pipe down into a column of limestone chips. A length of
100mm. dia. plastic drain pipe, about 2 metres long. The waste water
that drains from this column is virtually free of acid. I had mine
checked by the Environmental Protection Agency and was given permission
to dispose of the water down the drain.
This is a brief description of the units I've done. I hope that it is
of some use to you where ever you are.
steve harrison on fri 15 aug 03
I would be interested in your information re salt scrubbers. I have
built a few and would like to learn more about how it is best done to
> I can possibly give you a contact (off list cause I don't have
> to post this info publically) that may be able to help you with some