Q. What are the inside and outside
diameter of the
burner flare that fits on 3/4" pipe? 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”.
How far should
the flare stick into the forge? A. The flare should
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 chamber.
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.
Modified Side Arm burner require a blower? A.
No, this is an
atmospheric burner, it does not require a blower.
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
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.
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.
Do I need a regulator and ball valve
both on my hook up for my forge. A. Yes you need both, a
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.
have heard of Kaowool, Cer-wool, and
Insuwool, 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
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.
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.
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
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
Q. What size forge could
I run using a single 3/4" side arm burner? A. You could
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
let you figure the inside area of different size cylinders.
Q. How do I tune a Side Arm
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
What is the normal
operating pressure of the side arm burners? A. The normal
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 and design.
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"
letter Z size drill bit.
Q. Does the use of
a rigidizer on ceramic blanket decrease the thermal properties of the
Yes, I recently contacted the application engineering department at the
Unifrax Corporation and they said that the rigidier does in fact react
with the ceramic blanket at temperatures of 2000º F or greater and
decreases the thermal properties of the blanket.
Q. What is the
purpose of the idle circuit? A. The idle
used so that you can instantly drop your forge to a quiet idle when you
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
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
I 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
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
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
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
QuickStix™ PST® 561™ Pipe Sealant. The following url is
a link to the Loctite product information page for the pipe
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
device , and that is what is causing you your
problem. When 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.
There 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.
Is it true that gas
forges put out a lot of ultraviolet light? A. No, the only fuel
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
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 hole.
Q. How do I
properly light the gas forge? A. First make sure
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 getting burned.
Q. How is the Duraboard held 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
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 no
I run the side
arm burners off of natural gas instead of propane? A.
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
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
just 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
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#,
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
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
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
would say that you need at least two inches of the Durablanket for a
well insulated forge.
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
everyones needs. I guess it really depends on what kind of work
wanting to do with the forge. One of the main things is that the
design works for the type of work that you are going to do with it.
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.
the simple gas forge design and the square body forge design on my web
allow you to use the whole interior of the forge. Because on the
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
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 forge? A. Type 304/304L stainless steel is a
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
interior of the forge. When
installing burner assembly in the forge, the flare should not extend
the forge chamber, it should be up inside the Durablanket about a 1" to
1/2" to help protect the flare from the high heat in the forge chamber.
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
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 forge burner.
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
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