CONNECTING UP YOUR TORCH
There will be gas and oxygen that will have to be supplied to your torch. The best way to control this is
with a separate manifold. The reason for this is that you can then turn the torches on and off without touching the control valves
on the torch itself. You leave the torch set to its correct operating adjustment. This saves a lot of time since most time lighting
a torch is spent in getting the flame set correctly.
When using more than one torch, a means of connecting each one to the gas supply
must be arranged. This is a simple manual valve manifold that allows each torch to be turned on individually or in combination. This
manifold controls four torches, one set of valves for oxygen the other for gas. You can just as easily get by with a simple group
of fittings with hose barbs and no valves: you don't need the valves. The torches are connected to the regulator output and you turn
the torch on and off with the torch valves. And take the time hit in having to adjust the flame each time you turn on the torch.
having separate valves to turn on and off the torch, the setting of the torch knobs doesn't have to be disturbed. This saves considerable
time! You don't really need this kind of setup but the time saved makes it desireable.
A new manifold is being built that uses solonoid
valves and electrical switches to turn on the torches. This will save valuable space on the glass blowing console.
CONTROLLING OXYGEN AND GAS FOR YOUR TORCHES
Getting the oxygen for your torch is one of the most difficult problems to solve. Pressure tanks are heavy and have to be refilled
quite often, and have a way of waiting until you are in the middle of a critical glass operation before going empty on you.
to this problem is the oxygen concentrator. This is a machine that extracts oxygen from the air and concentrates it to over 95% purity.
The machine produces oxygen only while it is running so the hazard of having large quantities of oxygen stored on your premises is
The oxygen concentrator is available in several sizes from small 3 liter per minute up to large 20 or more liter per minute
machines. The cost is accordingly greater of course for larger machines. If you are going to do any long term glass blowing, an oxygen
concentrator is going to be the way to go.
A new oxygen concentrator costs on the order of $1000 U.S. or more. This is not reasonable
for most amateurs. The answer is a used machine. These machines are made for medical use by people that have certain types of lung
disease. Thus, there are huge numbers of these machines out there and a lot of them at bargain prices since they cannot be resold
for medical use.
Ebay used to be a source for the machines but the government came down on them for distributing a controlled medical
device without a license. It is all political since they allow numerous other controlled medical devices to be listed!
The used machines
are available from several suppliers on the web. (google oxygen concentrator, used) They range in price from $100 to around $1000
for one that is practically new.
The lifetime of the concentrator is long, about 30,000 hours. However, you don't want a machine that
is approaching that end. Ask for a machine that has under 20,000 hours on it. That will cost more but you will be less likely to have
a failure, plus the oxygen purity tends to drop somewhat as the machine gets towards the end of its service life.
Rebuilding the machines
is not difficult but it requires the set of parts, which will cost you as much as another used working machine. Not practical.
torches require a relatively pure oxygen flow that varies from a fraction of a liter per minute for the mini tip, to 15 liters per
minute for the large rosebud. The required pressure for the torches is 5 pounds per square inch.
The smaller most used tips use 3
to 5 liters per minute. This is a LOT of oxygen! You will find that out if you are buying oxygen in tanks! For the oxygen concentrator
that is no problem of course.
Oxygen concentrators come in two main sizes, 3 liter per minute and 5 liter per minute. There are other
sizes but they are rare and more expensive.
You can get by with one 5 liter unit. The largest tip will not operate at full heat but
it will be acceptable for most work. The 3 liter unit is too small for working glass sizes larger than one inch.
When buying the used
oxygen concentrator, explain to the dealer that you are not using it for medical purposes and do not need a certified machine, and
will sign a waivier that declares that the machine will not be used for medical oxygen. This will drop the price of the machine considerably
since the dealer is able to sell you a machine that has not had to be rebuilt.
The output of the oxygen concentrator is through a
front panel connector. You can adapt a hose barb to this and run this to your torch or manifold. The flow setting on the oxygen concentrator
is set to allow right at 5 liters per minute with the oxygen valve open. You can set it to higher than 5 liters per minute when using
the large rosebud tip and get about 7 liters per minute at somewhat reduced pressure, but it will give a noticeably larger flame.
This is not harmful to the oxygen concentrator.
There are two practical gas sources for your torches. The optimum setup uses
natural gas from the wall valve with an oxygen concentrator. You never have to worry about running out of gas. This is practical only
if your shop has natural gas service.
Propane is the other practical solution. The small 5 gallon tanks used in barbeque pits are
cheap, available everywhere, and easily exchanged or refilled at many hardware stores and propane dealers. The entire tank, a fill
of propane, and a regulator costs less than $100 new. The amount of gas in a 5 gallon tank is truely amazing. You might go for half
a year on one fill of the tank depending on how many times you use the largest tips.
One disadvantage of propane tanks is that you
are storing a large qauntity of flammable gas in your shop. The hazard is minimal, but you must always be aware of any smell of gas.
A regulator for the tank is set to 3 to 5 pounds per square inch and connected to the manifold for your torches. It is best to use
professional gas fittings for these connections, however ordinary copper tubing connections are suitable. If hose barbs are used,
be sure to use clamps on each one so the hose cannot be accidently pulled loose by a child or a pet.
The picture above is the natural gas compressor that is used to raise the pressure of the gas from the wall valve up to that required
for the torches. Natural gas is supplied to homes at approximately 3 ounces pressure per square inch. To operate the torch, 5 pounds
per square inch is required, over 25 times as high as what is available at the wall valve.
The compressor raises the pressure from
3 ounces up to the 5 pounds. A bypass regulator is used for maintaining the pressure so the compressor runs continuously and draws
only what gas is needed from the wall valve to maintain the pressure. The compressor is a small diaphragm type that has a maximum
pressure of about 10 psi. A flow rate of about 5 liters per minute is all that is necessary. The colored tanks are resivours for the
gas, however they are not necessary. The output of the compressor regulator can be connected directly to the manifold.
A manual manifold used to control gas to a set of 4 torches
A set of two 5 liter per minute oxygen concentrators used to supply oxygen to the glass blowing torches.