burning inside burners/long story

updated wed 29 dec 04

mel jacobson on tue 21 dec 04

this should never happen.
period.

it is not how burners work.
period.

back flashing into the tube is
always caused by some air/gas
problem. (high winds can cause this to happen
in outdoor kilns.)

it happens at the farm when too much
air and low gas causes the nils lou burners
to back burn.

my guess is:

you have too much primary air moving into the
tube, and, the gas pressure is too low.
so the flame jumps back to the orifice and burns there.

try some aluminum foil over the primary air
intake. experiment with it. half over, quarter over.
when the burner is working fine, and you have heat
building in the kiln the foil can be taken away.
(need we mention good gloves?)

we have used kaowool plugs in the primary air
holes of some burners like weed burners etc.
but, without question, aluminum foil is a good
air deflector. it can be used, for example, if you
want a really dirty flame in raku, or if you are trying
to get early reduction in shino. it can also be crimped
on a burner/behind the primary air to keep wind from
blowing out the flame. sort of a big funnel protector.

some burners do not have adjustable bellows on them.
and, if you get gobs of primary air. the mix of gas and
air gets out of synch. then you have problems with
`back flashing`. there is probably some technical term
that is more important, but i call it back flashing. of course
the burner is not working, the tube is turning red hot, and
the tube will break down over time. it is the same thing
that people will do when pushing burners too far into the kiln.
keep the burners one inch from the burner port. the paint should
be good on the burners after 100 firings.

i bet these are really short burners.

my old denver burners can do this, low gas, bellows open
way up. back flash. i always close my bellows way down (half inch)
in the early stages of firing...as soon as things are working
just fine i open them up. (half hour)

many folks never experiment with burners or firing technique.
they just turn on the kiln and fire.

i love to fire with really low pressure, high pressure, one burner high,
one low, lots of air, no air. watch the pyrometer or oxyprobe. see what
happens.

very few people know that you can move heat around in a kiln.
move heat from side to side. top to bottom.
high gas pressure will cause the bottom to get hot first.
low gas makes a hot top.
turn one burner on full, one on half...heat moves.

vince will always argue that if you get things in perfect balance
a kiln will fire the same way every time. that is a wonderful concept.
i agree.

but, weather is never the same, loading is never the same, barometer is
never the same. far too many variables to make things work the same
every time.

a big commercial kiln, indoors, tall stack, forced air burners and firing
the same kind of pots over and over should be able to fire by the
numbers every time. that is not possible for most potters.
learn how your kiln fires.
understand the burners.
understand gas pressure/air mix.
experiment. keep good records.

god, people will fuss with 800 test tiles, 500 glazes
and not have a clue how a kiln works.
(and, scared out of their pants to experiment with the kiln.)
if you are frightened of your kiln, well it will bite you one day.
big bite. don't show fear, they can smell it.
mel

From:
Minnetonka, Minnesota, U.S.A.
web site: my.pclink.com/~melpots
or try: http://www.pclink.com/melpots
new/ http://www.rid-a-tick.com

Michael Wendt on tue 21 dec 04

On occasion my Olympic burners flame down into the tube. When this happens,
I turn the kiln off and relight.
To add to Mel's comments, be careful to check your burners for insects and
especially spiders. More than once I have had spiders build webs down in the
burners and it happens overnight, not because we fire too seldom.
Burning back in the tube can also lead to soot buildup inside the burner and
later in the firing, that burner won't fire properly so check burners for
soot if they are run at very low turndown rates for extended times.
Regards,
Michael Wendt
Wendt Pottery
2729 Clearwater Ave
Lewiston, Idaho 83501
USA
wendtpot@lewiston.com
www.wendtpottery.com

wjskw@BELLSOUTH.NET on tue 21 dec 04

Just like your car, water heater and furnace. Never talk about
any of them in front of it.

It remembers, and will wait to piss you off, just when you need it
most. Isn't that one of Murphy's Laws?

Happy Holidays to all,
Wayne Seidl




if you are frightened of your kiln, well it will bite you one day.
big bite. don't show fear, they can smell it.
mel

Laurie on tue 21 dec 04

I was going to send the reminder about spiders and bugs, too, since my
Geil is outside.

My last firing was on a particularly windy day last month. I have never
had flashback into the burners before that day. It was kind of scary
and it happened because I had the door and flue wide open so the wind
just whirled around inside and through the kiln. Once the burners were
lit and the door closed, no problem. But I did have to improvise some
extra sheet metal around the kiln area to stop the wind messing with my
burners!

Then on top of that I had one burner that just didn't want to stay lit.
Shut everything down and got a pipecleaner. Earwig in the orifice. They
always invade the sprinkler heads, so why not the kiln burners, too.
One of the drawbacks to having an outdoor kiln. But my new rule is to
always run a pipecleaner through the orifices before each firing.

Darn bugs!!

Laurie
Sacramento, CA
http://rockyraku.com
Potters Council, charter member
Sacramento Potters Group, member


On Dec 21, 2004, at 7:12 AM, Michael Wendt wrote:

> On occasion my Olympic burners flame down into the tube. When this
> happens,
> I turn the kiln off and relight.
> To add to Mel's comments, be careful to check your burners for insects
> and
> especially spiders. More than once I have had spiders build webs down
> in the
> burners and it happens overnight, not because we fire too seldom.

Pfeiffer, Dan R (Dan) on tue 21 dec 04

>>this should never happen.
>>period.

But is this true of burners using LP? I have tried cutting the air way down
using the plate on the burner and a mirror on the floor to watch the flame
in the tube and could not find a setting that would not have the flame jump
back into the tube. I put a wire screen over the top and this keep the flame
out of the tube for a short time but before long it was back in the tube.
While it was out of the tube the flame was a nice blue with no soot on low,
looked great but could not keep in there. The best I can make out is that
the short cheap burners that Olympic and the like use are make for natural
gas and just do not work well on LP. LOTS of soot on a low flame but in the
end it will fire the kiln and get the job done. My thoughts are to run it
until it dies and then rebuild it with better burners.

Does anyone have this working right on LP?

Dan & Laurel in Elkmont

Hank Murrow on tue 21 dec 04

On Dec 21, 2004, at 8:15 AM, Pfeiffer, Dan R (Dan) replied to this:

>>> this should never happen.
>>> period.
>
> But is this true of burners using LP? I have tried cutting the air
> way down
> using the plate on the burner and a mirror on the floor to watch the
> flame
> in the tube and could not find a setting that would not have the flame
> jump
> back into the tube. I put a wire screen over the top and this keep the
> flame
> out of the tube for a short time but before long it was back in the
> tube.
> While it was out of the tube the flame was a nice blue with no soot on
> low,
> looked great but could not keep in there. The best I can make out is
> that
> the short cheap burners that Olympic and the like use are make for
> natural
> gas and just do not work well on LP. LOTS of soot on a low flame but
> in the
> end it will fire the kiln and get the job done. My thoughts are to run
> it
> until it dies and then rebuild it with better burners.

Dear Dan;

You have a point here about the differences between burners designed
for specific fuels. For example, the Eclipse injectors that I use on my
kilns are wonderful for both natural gas and propane, but for the
latter fuel, they add a brass section to accommodate the longer
skinnier shape of the propane under higher pressure, so the mixer
entrains the right amount of air for complete combustion. Also, I would
mention my advocacy of flame retention tips like the Eclipse product
they call "Sticktite". These allow a small amount of the gas/air
mixture to form an annular 'ring' on the fire side of the tip, through
which the main supply flows. Once it is lit, the 'ring of fire' lights
the main supply as it passes through and they do not backfire. This
system is more expensive, and that is why you don't find it on
inexpensive kilns. But it is nearly bulletproof, and very efficient in
the bargain. On my Doorless Fiberkiln, I use a 2" Eclipse mixer feeding
a manifold with 16 small Sticktite tips for a very efficient and even
firing arrangement. It all runs off one
7/32" orifice!

Hope I have explained this adequately, and I wish we could post
drawings to this list!

Hank
www.murrow.biz/hank

Vince Pitelka on wed 22 dec 04

> But is this true of burners using LP? I have tried cutting the air way
> down
> using the plate on the burner and a mirror on the floor to watch the flame
> in the tube and could not find a setting that would not have the flame
> jump
> back into the tube.

Dan -
Part of what I write below responds to the off-list message you sent to me,
but I decided to respond on Clayart, since others may be interested in this
information.

It sounds like your orifices are a little large for those burners. I am
assuming that you mean 11 WCI rather than 11 PSI. 11 WCI is pretty standard
for a set-pressure propane regulator. In the message you sent me off-list,
you said that the orifices were 1/8". It seems to me that this would not
deliver enough gas velocity in a small tube burner, especially at low
settings.

In the off-list message you asked about cutting the burner tubes back,
threading the ends, and installing flame-retention tips. That would
probably be a good idea, just in terms of general burner function. But a
flame retention tip serves to prevent flame-off (where the flame jumps off
the tip of the burner) more than to prevent back-burning. But that may be
necessary, because if you reduce the size of the orifice, increasing the
velocity of the gas jet, the entrainment of primary air, and the speed of
the air/gas mixture passing down the burner tube, you might have problems
with flame-off rather than back-burning. On an inferior burner design with
poor flame-retention properties, it is often one or the other.

In an earlier message I explained back-burning - that's where the air/gas
mixture is moving down the burner tube slower than the speed of combustion,
and thus the flame jumps up the burner tube to the orifice. Flame-off is
just the opposite. We always want the air-gas mixture to move down the tube
faster than the speed of combustion, in order to prevent back-burning, but
if there is nothing to ensure that combustion takes place right at the
burner tip, then the flame gets blown right off the tip, and often
extinguishes itself. The purpose of a flame-retention tip is to create
turbulence at the tip, increasing the effective mixing of air and gas, thus
accelerating combustion, so that it occurs right at the tip. There are an
extraordinary variety of effective designs for flame retention tips, and the
one thing they all have in common is that they create turbulence in the
stream of air/gas mixture right at the burner tip.

It seems to me that Olympic was cutting corners in using a tube burner with
poor flame-retention properties, and now you have to do some adaptation to
get it to work properly. Seems to me that Olympic should be making those
modifications free of charge, in order to get your kiln working properly.

I think you had the right idea regarding installation of flame-retention
tips. If the tubes on your burners are threaded into the intake bell
assembly, I'd just dismantle them and throw away the tubes. They will be a
standard pipe size, so just buy slightly shorter black iron pipe nipples in
the same size (they are inexpensive), and then purchase the appropriate-size
flame retention tips (they are not inexpensive) from Marc Ward and
reassemble the burners. Check with Marc on the appropriate orifice size for
those burners and change them if necessary. He will have a recommendation.
You can simply silver-solder over the tips and re-drill them to the size
Marc recommends, or you can buy new orifice tips with smaller holes.

There is nothing wrong with a good pipe burner. They can work extremely
well, as long as the intake bell and primary air shutter are well designed,
the orifice is the right size and is properly placed, and there are proper
flame-retention accommodations at the burner tip.
Good luck -
- Vince

Vince Pitelka
Appalachian Center for Craft, Tennessee Technological University
Smithville TN 37166, 615/597-6801 x111
vpitelka@dtccom.net, wpitelka@tntech.edu
http://iweb.tntech.edu/wpitelka/
http://www.tntech.edu/craftcenter/

william schran on wed 22 dec 04

Dan wrote:> The best I can make out is that
the short cheap burners that Olympic and the like use are make for natural
gas and just do not work well on LP. LOTS of soot on a low flame....<

I planned to run my Olympic on natural gas, but where the kiln was to
be located and insufficient gas pressure made it necessary to go with
propane. Even with #40 orifices and primary air wide open, I could
only get a long yellow flame. Called Olympic, spoke with Bob Hauger
who said this was normal - well not for any of the number of burners
I've used before!

Per my other post, switching out existing cheap burners for the Ward MR750's

Bill

wjskw@BELLSOUTH.NET on wed 22 dec 04

Admittedly, I don't fire a gas or wood kiln (yet).
But the principles of combustion are the same for woodstoves,
fireplaces, furnaces etc.
If you're getting "blowback", where the gas is igniting into the
burner tube, instead of going into the kiln,
could there be a restriction of some sort in the firing chamber or
flue, which isn't allowing through flow? Too much pressure (gas?)
could also cause this blowback. I've seen that with my water
heater.
Just a "stupid newbie" thought.
Wayne Seidl

-----Original Message-----
From: Clayart [mailto:CLAYART@LSV.CERAMICS.ORG] On Behalf Of Hank
Murrow
Sent: Tuesday, December 21, 2004 8:45 PM
To: CLAYART@LSV.CERAMICS.ORG
Subject: Re: burning inside burners/long story

On Dec 21, 2004, at 8:15 AM, Pfeiffer, Dan R (Dan) replied to this:

>>> this should never happen.
>>> period.
>
> But is this true of burners using LP? I have tried cutting the
air
> way down
> using the plate on the burner and a mirror on the floor to watch
the
> flame
> in the tube and could not find a setting that would not have the
flame
> jump
> back into the tube. I put a wire screen over the top and this keep
the
> flame
> out of the tube for a short time but before long it was back in
the
> tube.
> While it was out of the tube the flame was a nice blue with no
soot on
> low,
> looked great but could not keep in there. The best I can make out
is
> that
> the short cheap burners that Olympic and the like use are make for
> natural
> gas and just do not work well on LP. LOTS of soot on a low flame
but
> in the
> end it will fire the kiln and get the job done. My thoughts are to
run
> it
> until it dies and then rebuild it with better burners.

Dear Dan;

You have a point here about the differences between burners designed
for specific fuels. For example, the Eclipse injectors that I use on
my
kilns are wonderful for both natural gas and propane, but for the
latter fuel, they add a brass section to accommodate the longer
skinnier shape of the propane under higher pressure, so the mixer
entrains the right amount of air for complete combustion. Also, I
would
mention my advocacy of flame retention tips like the Eclipse product
they call "Sticktite". These allow a small amount of the gas/air
mixture to form an annular 'ring' on the fire side of the tip,
through
which the main supply flows. Once it is lit, the 'ring of fire'
lights
the main supply as it passes through and they do not backfire. This
system is more expensive, and that is why you don't find it on
inexpensive kilns. But it is nearly bulletproof, and very efficient
in
the bargain. On my Doorless Fiberkiln, I use a 2" Eclipse mixer
feeding
a manifold with 16 small Sticktite tips for a very efficient and
even
firing arrangement. It all runs off one
7/32" orifice!

Hope I have explained this adequately, and I wish we could post
drawings to this list!

Hank
www.murrow.biz/hank

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Louis Katz on wed 22 dec 04

The reduction in diameter in a flame retention ring results in an
increase in velocity which up to a certain limit keeps the flame from
traveling back into the throat and back burning. The flame burns back
towards the orifice as the gases move out through the throat. Stasis is
achieved and the flame burns where these two processes meet. This
happens unless the flamestarts further out than the small holes drilled
in the ring. These slow the gas stream flowing through them down far
enough that they can light and act as pilots for the main flame.
Trouble happens when there is turbulence, as can be caused by wind,
large junk in the burner or rotten castings. All burner systems have a
minimum amount of gas that they will work with before they backburn.
Smaller orifices run at higher pressures allow more air to be
entrained in the gas. They allow more kinetic energy to be imparted to
the gas air stream. Or another way to look at it is if more air is
entrained it has to move faster to get through the burner.
Pipe burners without flame retention rings operate "well" only in a
narrow range of BTU's. The are prone to back burning much sooner than
those with retention rings, they blow out easier, and they entrain less
air than a well designed and built venturi.
Louis


> But a
> flame retention tip serves to prevent flame-off (where the flame jumps
> off
> the tip of the burner) more than to prevent back-burning.
http://www.tamucc.edu/~lkatz/cs/files/

Pfeiffer, Dan R (Dan) on wed 22 dec 04

>>Admittedly, I don't fire a gas or wood kiln (yet).
But the principles of combustion are the same for woodstoves,
fireplaces, furnaces etc.
If you're getting "blowback", where the gas is igniting into the
burner tube, instead of going into the kiln,
could there be a restriction of some sort in the firing chamber or
flue, which isn't allowing through flow? Too much pressure (gas?)
could also cause this blowback. >>

This happens with the lid up and no shelves in the kiln as well as with a
full load so I don't think there is a problem with back pressure on the
burners is the root cause. I think Vince has it right the gas is too slow to
move the flame up the tube.

This looks to be like so many other things I buy any more, you pay a lot and
than get to reengineer it to make it work right.
This leave us with the option of doing nothing and putting up with the soot
and wasted heat or spending time and money replacing the whole burner
system.

On the up side of this someone who is good with burners could sell a drop in
replacement burner system and may find lots of people who would buy.

Dan & Laurel

Ivor and Olive Lewis on thu 23 dec 04

Dear Dan Pfeiffer,
As Mel often tells us, think about the science. I agree and this is
what I came up with.
In this case its about both Physics and Chemistry.
You, and others plagued by this problem of "Flash Back", need to get
into the archives (No,not Clayart Arch's), either via Chemical
Abstracts or somewhere in Google and search for the Physics of Flames
and Flame Velocity.
Simply put, there are relationships between the composition of the gas
both in terms of the chemical which is the fuel gas , the quantity of
oxygen in the mixture, the rate of flow, the velocity of flow and the
speed at which gas will burn back to the source of the gas.
Good burners have Flame Retention Nozzles.
The purpose of using a grill or gauze over the end of the nozzle is to
cool the flame front to a low enough temperature to prevent
pre-ignition below the gauze and subsequent burning at the orifice
nipple.
To prevent flash back the velocity of gas flow has to be faster than
the rate at which a flame front will travel in the opposite direction
to the flow of gas. The lower the Oxygen concentration in the gas air
or gas oxygen mixture the slower the flame velocity. If there is
insufficient gas in the burner between the nipple and burner orifice
air will move backwards and the flame will travel with it as the gas
burns. This leaves your gas burning as it issues from the nipple.
Except for Hydrogen or coal gas I would expect a white to smoky flame
from any other fuel gas.
This should be explained in books which are written about firing
kilns. Nils Lou does cover the topic in "The Art of Firing", ISBN
90-5703-16-25. See the Index for "Flashback". As well as Nils' book
try to get hold of the book by Harry Memmott, "An Artists Guide to
Firing Kilns", a private publication from Victoria College, Prahran
Campus, Victoria, Australia. (Look for a Web Site)
Best regards,
Ivor Lewis.
Redhill,
S. Australia.

Vince Pitelka on thu 23 dec 04

> Hey, nobody's mentioned the trick of stainless steel wool in
> the burner to cause turbulence. Would that work here?

Earl -
I have not heard of that being used in venturi or tube burners. True
stainless wool would obstruct the burner too much. A coarser material (like
a scrubbing pad) that did not cause much obstruction but did cause
turbulence might actually work. It would have to be placed right at the
burner tip, in which case it would function much the same as other flame
retention systems that involve a screen or perforated plate over the burner
tip.
- Vince

Vince Pitelka
Appalachian Center for Craft, Tennessee Technological University
Smithville TN 37166, 615/597-6801 x111
vpitelka@dtccom.net, wpitelka@tntech.edu
http://iweb.tntech.edu/wpitelka/
http://www.tntech.edu/craftcenter/

Vince Pitelka on thu 23 dec 04

> The reduction in diameter in a flame retention ring results in an
> increase in velocity which up to a certain limit keeps the flame from
> traveling back into the throat and back burning. The flame burns back
> towards the orifice as the gases move out through the throat. Stasis is
> achieved and the flame burns where these two processes meet. This
> happens unless the flamestarts further out than the small holes drilled
> in the ring. These slow the gas stream flowing through them down far
> enough that they can light and act as pilots for the main flame.
> Trouble happens when there is turbulence, as can be caused by wind,
> large junk in the burner or rotten castings.

Louis -
Just to clarify a bit, what you say is all true, but many flame-retention
tips do not have any reduction in diameter. In fact, many of the most
effective flame-retention designs feature a sudden expansion of the bore
diameter just before the tip of the burner. As the gas-air mixture passes
by that step-up, it creates turbulence.

In most venturi and tube burners, the air and gas is poorly mixed as it
passes down the burner tube, and a critical factor in all flame-retention
tips is that they create turbulence in the moving stream of air and gas in
order to thoroughly mix them. That speeds up combustion right at the tip,
and reduces the chances of both flame-off and back-burning.

I realize that you are speaking of a different kind of turbulence above -
that which occurs around the burner from wind. But I wanted to clarify that
turbulence is a key factor in the proper operation of flame-retention
designs. In the classical Eclipse and Stik-Tite flame-retention tips, the
reduced diameter of the main center hole is recessed back inside the tip,
and in combination with the ring of small holes surrounding the center hole,
there is a lot of turbulence occuring in a very small space. That's why
these tips are so effective.

Some people keep using the term "flame-retention ring." Aren't we talking
about flame-retention tips? As I understand it, a "flame-retention ring" is
a particular type of flame-retention device sometimes installed inside
burner tips.
- Vince

Vince Pitelka
Appalachian Center for Craft, Tennessee Technological University
Smithville TN 37166, 615/597-6801 x111
vpitelka@dtccom.net, wpitelka@tntech.edu
http://iweb.tntech.edu/wpitelka/
http://www.tntech.edu/craftcenter/

URL Krueger on thu 23 dec 04

On Wednesday 22 December 2004 08:57 am, Pfeiffer, Dan R
(Dan) wrote:
> This looks to be like so many other things I buy any
> more, you pay a lot and than get to reengineer it to make
> it work right. This leave us with the option of doing
> nothing and putting up with the soot and wasted heat or
> spending time and money replacing the whole burner
> system.

Or, say "I've had enough and I'm not going to take it
anymore!" and demand that the manufacturer either fix their
product such that it works to your satisfaction or refund
your money.

I would presume that if the manufacturer has been paying
attention to the posts to Clayart, which they should be as
we are their customers, they will realize that they are
getting bad press from this. If they wish to continue in
this marketplace they should be willing to work with you to
resolve your discontent. If they don't care then don't
hang too many hopes on their warranty because they won't be
in business much longer.
--
Earl K...
Bothell WA, USA
Will the orphans of war who survive to adulthood
be our friends or our enemies?

URL Krueger on thu 23 dec 04

On Wednesday 22 December 2004 10:39 pm, Vince Pitelka wrote:
>In fact, many of the most effective
> flame-retention designs feature a sudden expansion of the
> bore diameter just before the tip of the burner. As the
> gas-air mixture passes by that step-up, it creates
> turbulence.

Hey, nobody's mentioned the trick of stainless steel wool in
the burner to cause turbulence. Would that work here?

--
Earl K...
Bothell WA, USA
Let no soldier be left behind,
when we bring them home.

Paul Herman on fri 24 dec 04

Hi Vince and Earl,

My frind Joe Winter made his own 'Bendel" burners. He solved the back
burning by fashioning a burner tip from a coil of scrap electric element
wire, made into a loop and fastened inside the tip. This seems to stir
the mix up just fine.

The Bendel burners still burn more yellow than my Ransom B-4s, though.
I've heard the Ransoms are not being manufactured anymore.

good firings,

Paul Herman

Great Basin Pottery
Doyle, California US
http://www.greatbasinpottery.com/

----------
>From: Vince Pitelka
>To: CLAYART@LSV.CERAMICS.ORG
>Subject: Re: burning inside burners/long story
>Date: Thu, Dec 23, 2004, 9:08 PM
>

>> Hey, nobody's mentioned the trick of stainless steel wool in
>> the burner to cause turbulence. Would that work here?
>
> Earl -
> I have not heard of that being used in venturi or tube burners. True
> stainless wool would obstruct the burner too much. A coarser material (like
> a scrubbing pad) that did not cause much obstruction but did cause
> turbulence might actually work. It would have to be placed right at the
> burner tip, in which case it would function much the same as other flame
> retention systems that involve a screen or perforated plate over the burner
> tip.
> - Vince

Vince Pitelka on fri 24 dec 04

> My frind Joe Winter made his own 'Bendel" burners. He solved the back
> burning by fashioning a burner tip from a coil of scrap electric element
> wire, made into a loop and fastened inside the tip. This seems to stir
> the mix up just fine.

Paul -
That was, in fact, a "flame retention ring," installed within an existing
burner. My big car kiln in my studio in Northern California had six cast
iron tube burners scavenged from a bank of fifteen that ran a heating
boiler. Each one had a ring of heavy iron wire snapped into cast-in tabs
just inside the burner tip, and as in those Bendel burners, it created
plenty of turbulence for good flame retention. It doesn't take much. I
have fabricated numerous flame retention tips for pilot burners, tuber
burners, and venturis, and they have worked well. It really is a fairly
simple concept.

As mentioned in a previous message, there are so many different designs for
flame-retention tips or nozzles, and almost all of them seem to work well.
I think that this is one of those situations where a potter or kiln builder
with solid practical experience can come up with a flame-retention tip that
works as well as any design from a combustion engineer.
Best wishes -
- Vince

Vince Pitelka
Appalachian Center for Craft, Tennessee Technological University
Smithville TN 37166, 615/597-6801 x111
vpitelka@dtccom.net, wpitelka@tntech.edu
http://iweb.tntech.edu/wpitelka/
http://www.tntech.edu/craftcenter/

Jim Larkin on sun 26 dec 04

Vince says burners, tuber=20=20
burners, and venturis, and they have worked well. It really is a fairly=20=20
simple concept.>
Somewhere long ago I saw and have successfully used washers a little
smaller diameter than the inside diameter of the burner tip, drilled
multiple holes in the washer, and spot welded the washer inside the mouth
of the burner. You have to use a ring washer (one with a big hole in the
middle) or cut the middle out to size yourself so that you don't choke
off the diameter of the burner too much.
Jim
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