Q. What size Propane regulator do I need to run a 3/4"
atmospheric burner? A.Gas Forge Propane Regulator sizing.
Everybody keeps saying that you need a 0 to 30 High Pressure
Regulator and they leave out a very important factor. The BTU
output of the regulator needs to put out at least 100,000 BTU,s
for each 3/4" burner that it will be hooked up to. A lot of the
so called 0 to 30 high pressure regulators only put out 40,000
BTU. The same goes with the POL fitting it needs to be capable
of 250,000 BTU output. This is very important information when
building a gas forge.
Q. What is the best method for coating the Ceramic Blanket
once it is inside your gas forge? A. Forge coating
Step 1: Apply an Ins-tuff Ceramic Fiber Rigidizer
The first thing you need to do to the ceramic blanket once it is
installed in the forge is coat it with a Rigidizer, this
provides a harder and more resistant, but less resilient,
surface on the material being treated.
Step 2: Apply the Kast-O-Lite 30 coating
Mix the Kast-O-Lite 30 to a thick paste, just keep adding water
slowly until you get a pasty consistency that you can paint on
with a paintbrush the consistency of sour cream. Spray the
ceramic fiber insulation down using water with a hand spray
bottle to wet it lightly if you are putting it directly on the
ceramic blanket and not using a rigidizer. If you use a
rigidizer first you do not need to moisten the blanket.
Next, apply the Kast-O-Lite 30 to the wool using a paintbrush,
covering all exposed wool surfaces. To cure it, you want to dry
it slowly when installing a lining, we do like to seal any
insulation back up prior to casting against. Any insulating
product will be porous and may pull moisture from a cast lining.
While we have used mortar to seal these areas, we have also
utilized sodium silicate. You are looking to add a barrier to
seal the surface so the back up lining does not act like a
sponge. This is one of the reasons that you put a good coating
of Rigidizer on the ceramic blanket before applying the
refractory When casting refractory products, you have a
cure period after casting. This is generally 24 hours. We have
found for low cement materials, it is best to cover them to hold
the moisture in and prevent the surface from drying out to
quickly. It is best to cure evenly. If these type of products
Cure too rapidly, the surface will crust over then must crack to
allow moisture to dissipate through the surface. I am sure if
you google concrete curing, you will find that it may be best to
cover with moist burlap and mist water over a period of time.
This is to prevent the surface from taking a set prior to the
lining curing evenly. The same applies to other castables.
When it comes to dry out, the slower you can dry a product, the
better the properties are. You are trying to soak heat into the
product to remove moisture. The lining gains strength when this
occurs. The deeper you can soak heat into the lining, the
stronger the product will be. Then fire up the forge just
briefly and shut it down. Do this several times, allowing it to
cool down in between and increasing the on-time with each
subsequent cycle. You'll see water vapor evaporating the first
few times you do this. Finally, fire it up and bring it up to
full temp to cure it fully. You will probably want to apply at
least two coats of Kast-O-Lite 30 in this manner,it's a little
time consuming but makes for a more robust coating. A 1/4" layer
is a good thickness to shoot for. If you are going to apply
Plistix 900F over top of the Kast-O-Lite 30, be sure to fully
cure the Kast-O-Lite 30 first.
The same procedures described above can also be used if you are
going to use Satanite or Greenpatch 421 instead of the Kastolite
30 LI using the same guidelines. I personally use The
Greenpatch 421 coating because of the following. It is a
premix and Air Set, this is better because it cuts out a lot of
the user error involved with ceramic coatings.
Step 3: Apply the Plistix 900f coating Plistix 900F
Mixing Instructions: (Note) This method is for if you are
applying the Plistix 900F directly onto the ceramic blanket and
not first coating it with a rigidizer or Kast-O-Lite 30.
Plistix 900F is in a powder form and is mixed with water to the
consistency of a thin milkshake it is then applied to the
refractory by dabbing it on with a paint brush, brushstrokes
tend to pull the fibers apart. It does not dissolve so it must
be continually stirred during use.
Application Instructions: If you are applying the Plistix
directly on the ceramic blanket you can mist the blanket with a
little water to help slow the drying. The Plistix can be coated
over Loucast 3000, Kast-O-Lite 30, Satanite, Rigidizers or other
high temperature coatings. Make sure the ceramic coating
is dry before applying the Plistix Drying and Curing
Instructions: After the Plistix installation is complete,
Plistix 900F may be left to air dry for an indefinite period as
long as freezing does not occur. It is recommended that
chemical setting Plistix 900F be prevented from air drying for
any significant amount of time prior to bake out. If an
extended time interval between installation and bake out is
expected, longer than a week cover the chemical bonded plastic
surface with plastic sheeting or use a liquid membrane concrete
curing compound to keep the plastic moist. Once material has air
dried to a hard set your forge is ready to use. The first
firing should be done with a low flame allowing the refractory
to warm up slowly to avoid thermal shock .
Q. What are the inside and
outside diameter of the burner flare that fits on 3/4"
A. The nominal
inside diameter of the flare is 1.049 and outside diameter
of the large end of the flare is 1-3/8”.
Q. How far should the flare stick into the
forge? A. The flare should not extend down into
the forge chamber it should be up inside the Durablanket about a
1" to help protect the flare from the high heat in the forge
Q. What size pipe do you use to mount the side
arm burner assembly? A. For the 3/4" pipe
burners I like to use 1 1/2” schedule 80. You can also use 1
1/2" schedule 40 pipe if you want, the schedule 80 is just a
little thicker and gives you more a few more threads.
Q. Does the Modified Side Arm burner require a
blower? A. No, this is an
atmospheric burner, it does not require a blower.
Q. What is the purpose of the burner flare or flame holder
on the end of propane burners? A. To keep the
flame from blowing off the burner's end by lowering the pressure
of the incoming gas air mixture. This lowered pressure
also prevents the flame from burning its way back up the mixing
Q. I am building a round body forge out of pipe, what is
the best location for the burner or burners? A. The
best location for the burner is 10 to 15 degrees off top dead
center. This helps to prevent the heat from radiating
up the burners. Plus it helps to create a swirling action of
the hot gases inside the forge body.
Q. What size opening should I have in the ends of the forge
and can I close off one or the both ends of the forge? A.
You need at least a 4" to 4 1/2" square opening in one end to let
the forge be able to breathe.
Q. Do I need a regulator and ball valve both on my hook up
for my forge. A. Yes you need both, a regulator is
needed to control the operating pressure going to the
burners. A propane tank can have around a 125 psi, you need
to be able to regulate it down to a range of 3 to 35
psi. A regulator can not be used as a shut off valve,
if you notice most propane regulators ratings do not go down to 0
psi. Q. I have heard of Kaowool, Cerablanket, and
Inswool, but I have not heard of Durablanket. Are all of
these products the same? A. These are all different names of
ceramic blanket made by different manufactures, they all come in
different thickness, temperature ratings and different
densities. You want to use the the 8# density with 2300
degrees temperature rating or greater. The UnifraxCorporation has manufactured Fiberfrax
high temperature insulation products since 1942.
Q. I am wanting to line the inside of
my 10" pipe forge or propane can forge with 2 inches of ceramic
blanket lining, should I use the 1 layer of the 2" or 2 layers
of the 1"? A. You should use two layers of the 1" ceramic
blanket, because it will be easier to form to the shape inside
of the forge. The 2" is a lot harder to work with.
Plus if you tear up the inside layer of the ceramic blanket, you
can replace it and not have to replace the outer layer, so this
will be a lot cheaper when it comes time to reline the
forge. The 2" blanket can be used for larger forges and
for making movable forge doors.
Q. I’m new to propane equipment and fittings so I’m
not sure how the burner pipe nipple is attached to the propane
hose. What fitting is required between the actual burner and
the hose coming from the regulator? A. You will
need a 1/4" ball valve and a 1/4" x 1/8" threaded bushing,
to go from the propane hose to the 1/8" nipple on the burner.
Q. I am thinking about building my own flare and welding a nut
onto the end of a piece of 1/8" schedule 40 pipe to attach my
Tweco tip too, do you think that this will work o.k.?
A.One of the important things about any atmospheric burner is
that you get the jet centered in the burner tube. Any time
you start adding and welding things on you run the risk of getting
it off center and diminishing the burner performance. The
flare is also critical, I have had a lot of people call and
say that they can not get there burner to run right, and then find
out that they made there own flare. That they thought was
close enough. If you read on Ron Reil's web site he states
the importance of the proper flare. I am not saying this to
try to get you to buy my products, but to save you some of the
troubles that others have experienced in building them.
Q. What size forge could I run using a single 3/4" side arm
burner? A. You could build a forge 10" in outside
diameter with 2" of Durablanket insulation and 10 to 12 inches
long with one side arm burner for general forge work. The
rule of thumb for side arm burners to forge volume is: (1) 3/4"
side arm burner for every 350 cu/in of interior forge space if you
are wanting to achieve forge welding temperatures. Note: these
figures are for a properly insulated forge. The following
links are to a couple of online calculators that will let you
figure the inside area of different size cylinders.
Q. How do I tune a Side Arm Burner? A. To tune a Side Arm
Burner you will need to remove it from the forge and work with
it open air. I like to tune them when it is dark,
because it is easier to see the flame and different colors.
The first thing you need to do is adjust the position of the Tweco
tip inside of the reducing tee while the burner is lit, slowly
move it back and forth until you achieved an smooth and even
flame. You will also hear the sound of the burner change as
you move it also. The other thing you need to do is tune the
burner flare, moving it slowly back and forth to achieve the
best stable flame that will not flame out and will run at a
pressure range of 3 to 35 psi. You will probably end up with
a nozzle exposure of somewhere between 1-1/4" and 1-1/2". If
you have trouble getting you burner to run right, some of the
problems that I have seen are the hole that was drilled in the
pipe plug was drilled off center or crooked causing the gas jet
not to be in the center of the burner tube. I have also seen
metal shaving and Teflon tape inside of the contact tip, this will
cause a very erratic flame. Below is a picture of what your
flame should look like when you are finished tuning it.
Q. What is the normal operating pressure of the side arm
burners? A. The normal operating pressure of a 3/4" side arm
burner using a .035 contact for general forge work is 7 to 8
psi. This is not set in stone this gives you a good starting
point when setting your pressure, a lot depends on your forge size
Q. What size drill bit do you use to drill the hole in the 1 1/4"
pipe plug for the 1/8" x 4" nipple? A. I use the letter Z
size drill bit.
Q. What is the purpose of the idle circuit? A.
The idle circuit is used so that you can
instantly drop your forge to a quiet idle when you are removing a
piece from the forge, or tending to some other chore by simply
turning off the ball valve in the idle circuit. When you
return to the forge and simply turn the ball valve on the idle
circuit back on and instantly bring the forge back up to full
heat. You will discover that the forge will not lose its operating
temperature when in idle mode either. You will need to
adjust the needle valve to ensure a proper idle flame.
Q. Is it really necessary to have a choke on your side arm
burner? A. Having a choke on your burner will allow
you to better achieve oxidizing, neutral, or reducing, flames as
needed by simply adjusting the choke and the gas pressure.
had always thought the burner should come in at an angle and the
flame should vortex inside the forge to help prevent hot
spots? A. I have always felt that you really only need
to vortex the burner when you are running a blower driven gas
forge and not on a atmospheric forge. I feel that because
you are pushing the heat through so fast with the blower that you
need some time to let the heat disperse evenly in the forge
body. You do not have all that much flow with the
atmospheric burners, so it seems to spread more evenly. The
forge also has the flat firebrick bottom, every forge that I have
seen that had a flat bottom and a vortex burner the flame seamed
to hit a flat spot and wants to shot out the front opening giving
another hot spot or uneven heat. I am sure that there are
others that will disagree with this thinking, but these are the
findings from my own personal experience with forges over the
Q. Do you use any pipe
dope or pipe tape on your propane fittings and the threads on
the mig contact threads when you are assembling them?
A. Yes, I use Loctite® QuickStix™ PST® 561™ Pipe
Sealant. The following URL is a link to the Loctite
product information page for the pipe sealant.
Q. I fired up the
forge with no problem it put out a nice flame, but
then I went to fire it up again later on all I got was just a
minimal flame (looked like a cooking flame) with no
pressure registering on the gauge. As soon as I shut off
flow to the burner the pressure would come right back up any
ideas? A. It sounds like you are running a 20 # LP cylinder with an excess flow device , and that is what is causing you your
using a tank with an OPD valve with the excess flow device or
check valve, it is better to light the forge, starting with all of
the valves turned off. Then turn the triangular hand wheel
one complete (360 degree) then turn the forge on and light it
up. From here you can adjust slowly for a higher flame.
are a couple of other things that can cause you to have similar
problems, you need a full flow POL (tank fitting). There
are some that have an Excess Flow Valve built into them and
there are others that have a fixed orifice, these will not
work. The other thing is to make sure that you have the
proper LP regulator like the Fisher model number 67CH-743,
you can not use the regulators that they sell for gas grills and
small appliances; they do not have the BTU ratings that you
need. After a forge is up and running and one of the
burners starts to flutter, it may be so that the burner
is sucking in exhaust fumes from the forge openings.
it true that gas forges put out a lot of ultraviolet
light? A. No, the only fuel gas that puts out an
appreciable amount of ultraviolet light (UV) is hydrogen
(unlike hydrocarbon fuels, straight hydrogen gas has no free
carbon in the flame to "soak up UV and re-emit the radiant
energy in other wave lengths). As to the incandescent
interiors of forges, they put out a lot of infrared and visible
light. With the single exception of hydrogen flames, you need
about 6000 degrees or more to create UV. So, it is a serious
concern from electrical arcs and incandescent lamps, but not
from forges. (submitted by Michael Porter )
Q. What is the best way to cut the
Durablanket and the Duraboard materials? A. The
Durablanket can be cut with a razor knife with no problem.
When I cut the opening for the burner to pass through
the blanket, I use a small kitchen knife. This allows
you to cut the hole with the Durablanket inside the forge
body, insuring you proper hole alignment. The Duraboard
can also be cut using a key hole saw, wood hand saw, or a
jigsaw. The Duraboard is easily cut into any shape you
want using these methods. Always be sure to wear proper
respiration protection when working with these products.
Q. I am in the process of building a
gas forge and was wondering, would you suggest doors on both
ends or one end being sealed with a "pass through" hole that can
be closed? A. I feel that this would really
be a matter of personal preference, a lot would depend on what
kind of work you plan on doing with your forge.
A door in the back of the forge would be
far more flexible in use than a back with just a pass through
Q. How do I properly light the gas forge?
A. First make sure that your ball valve is shut off at the
burner or burners, then fully open the valve on the propane
tank. Set your regulator from 5 to 7
psi. You can either light a small piece of paper or
use a lit hand held torch. The piece of paper must
be placed inside the forge and then slowly open the ball
valve on the burner. If you chose the torch method , you
will need to place the torch in front of the forge opening and
slowly open the ball valve. Be sure to keep your
hands and arms away from the front of the forge to prevent
Q. How is the Duraboard held
in place in the doors of the forge? A. I have used
the QF-180 to glue it into place and I have also have used
10-32 screws taped through the sides of the doors to
hold it into place. Q. Which product is better when
building a gas forge the Durablanket or the Duraboard?
A. The Durablanket is better if you are building a round
or oval shaped forge and the Duraboard is used when making
square or rectangular shape forges, they have the
different thermal properties, 2 layers of 1" 8# density
Durablanket is about the same as 1"thick 18# density
Duraboard. I have used both products on forge doors with
Q.Can I run the side arm burners off
of natural gas instead of propane? A. I have never done it but I have been
told that you would need to double the orifice size for
natural gas. The big problem with running the burners on
natural gas is that you will need at least 15 psi of natural
gas and most residential gas services only have inches of
water column. If you have a commercial gas service you
should be alright.
Q. I have never set up anything like this before can you
tell me how the parts go from the propane tank to
the burner? A. Here is how
all the fittings go starting at the tank, the POL screws into
the regulator inlet, the hose screws into the regulator
outlet, then the ball valve screws into the other end of the
hose, then the 1/4 x1/8 bushing screws into the other side of
the ball valve, and then the 1/8" nipple of the side arm
burner screws into the bushing. There is a gauge port in
the side of the regulator that you remove for the gauge.
Q. Do I coat the
inside of the forge body with the Plistix 900F coating
before I install the Durablanket or do I just coat the
Durablanket once it is inside of the forge?
need to put the Plistix coating on the inside surface of the
Durablanket once you have the forge lined. You do not need to
coat the forge body or were the burner flares go through. You
just want the inside of the forge coated to help protect the
Durablanket and help reflect the heat.
Q. I am building a 10"round body forge and
insulating it with 1" Durablanket, what do I need to use to hold
the Durablanket in place ? A. You do not need
anything to hold the Durablanket in place it is rigid enough to
hold itself in place. Just make sure that you have a tight
fit when installing the blanket.
Q. On a multiple burner atmospheric gas forge using side
arm burners what do you recommend the spacing to be
between the burners ? A. I recommend the burners to
be 3 1/2" to 4" on center and no more, this will insure
that you get an even heat on your pieces of metal that you are
Q. How long will a gas forge with one side arm burner run
on a 20# propane cylinder ? A. A 20# cylinder will
last for about 7 or 8 hours when running around 7 or 8
psi. If you have problems with the propane tank freezing
up you might want to consider manifolding two 20# tanks together
are getting a larger cylinder. There is a picture of this
set up on my burner parts page.
Note: Blue Rhino and others that exchange 20#
cylinders clearly state on the label that the net weight is 17#,
however these are 20# tanks and they can be safely filled to this
capacity or very close to it at a propane dealer.
Q. Do I need to place some kind of spacers under
my fire bricks or do I just lay them on top Durablanket?
A. You can just lay the firebricks on top of the Durablanket
it will compress the Durablanket a little but it will be fine.
Q. I am wanting to build a large gas forge for pulling out
large scrolls, I am thinking about building it four foot
long. What do you think about this idea? A. I
would suggest building (2) two foot long forges that you could
butt together instead of building one four foot long. This
will give you a lot more flexibility, if you do not need the whole
four foot you can separate it and just use one of them.
Q. Can I get by using just one inch of Durablanket for
my gas forge insulation ? A. No, I would say that you
need at least two inches of the Durablanket for a well insulated
Q. What is the best gas forge design? A. This
seems to be one of the most asked questions that I get
anymore. I do not think that there is a perfect design that
meets everyone needs. I guess it really depends on what
kind of work you are wanting to do with the forge. One of
the main things is that the forge design works for the type of
work that you are going to do with it. I have seen
commercially built forges and homebuilt forges that look nice but
are really limited to what work you can do with them because they
have a small fixed opening in the front and the rear of the forges
that restrict the size of the work that you can put in the forge.
Both the simple gas forge design and the square body forge
design on my web site allow you to use the whole interior of the
forge. Because on the square body you can simply open the
front door or on the simple gas forge you can simply reconfigure
the bricks to have a larger front opening. The simple gas
forge is cheaper and easier to build due to the materials used.
I realize that the insulated firebricks are not the
greatest ends to have on a forge, but you are able to
configure them to the size needed for the work that you are doing.
The square body forge, with its open front and back doors
that you can remove or raise to let stock pass through is a good
all around design that seems to work well.
Q. How far should the burner flares stick into the
Type 304/304L stainless steel is a chromium-nickel material that
offers very good corrosion resistance up to 1600 °F, the
temperatures inside a forge body will far exceed these
temperatures ratings so you must keep the burner flares out of the
interior of the forge. When installing burner
assembly in the forge, the flare should not extend down into the
forge chamber, it should be up inside the Durablanket about a 1"
to a 1 1/2" to help protect the flare from the high heat in the
Q. I have a forge body that is 12" in diameter and 24" long,
how do I figure out how much ceramic blanket I will need to line
it with two layers? A. You take the forge diameter
times pi 3.14 and this will give you the length of the first layer
(12 x 3.14 = 37.68") and then subtract two inches from the
diameter to account for the first layer and multiply that diameter
times pi 3.14 (10 x 3.14 = 31.4"). So you would roughly need
6 running feet of 24" ceramic blanket to line a forge with those
Q. I recently saw a hand held torch outfit (weed burner) at
Harbor Freight will this work as the burner in a gas forge
? A. No, these weed burners were not designed to be
put into a forge and will not work in place of a properly designed
Q. Is there any benefit in having a heavy wall forge body over a
thin body forge like the 5 gallon bucket forge body?
A. There is no benefit in a heavy forge body, that is why I
recommend using a bucket for the forge body
Disclaimer Notice: Zoeller Forge specifically disclaims any responsibility or
liability for damages or injuries as a result of any
construction, design, use or application of information
contained on this web site.