What you need to know about Welding cylinder or bottles!

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Welding Cylinder Data (capacity is in cubic feet @ 2100 psi)            

Oxygen / Argon / Helium / Other High Pressure                  
Tank Designator Capacity     Height      Dia. (height w/o cap & valve)
        K                  251              51"         9"                                                         $250.00 each
        S                  156              46"          7 3/8" ;; always owner cylinders         $200.00 each
        M                  125              47"         7"                                                          $200.00 each
        Q                   92              30"          7 1/8" ;; always owner cylinders
        R                   20              14"          5 1/4"

Tank Designator Capacity        Height          Dia.
       #5                  350                  45"       12"                                                          $300.00 each
       #4                  150                  38"        8"                                                             $200.00 each
       #3                   75                   29"        7"

High Pressure Cylinders
Normal Dimensions
Model DOT Spec Tapping ID
Water Volume (cu in) Service Pressure (psi) Test Pressure (psi)
20 cf 3AA2015 3/4-14
5.013 5.263 13.750 10.5 220 2015 3360
40 cf 3AA2015 3/4-14
6.670 7.000 17.400 23.5 490 2015 3360
55 cf 3AA2015 3/4-14
6.670 7.000 22.625 29.0 670 2015 3360
80 cf 3AA2015 3/4-14
6.626 7.000 32.375 46.5 1010 2015 3360
122 cf 3AA2015 3/4-14
6.626 7.000 43.000 58.0 1360 2015 3360
125 cf 3AA2265 3/4-14
6.626 7.000 43.000 58.0 1360 2265 3775
150 cf 3AA2015+ 3/4-14
7.045 7.375 46.563 61.0 1660 2015 3360
224 cf 3AA2015 3/4-14
8.500 9.000 51.000 113.0 2640 2015 3360
277 cf 3AA2265 3/4-14
8.500 9.000 51.000 117.0 2640 2265 3775
300 cf 3AA2400 3/4-14
8.750 9.250 55.000 139.0 2990 2400 4000

Cylinder Sizes


#4 $200.00

#5 $300.00


S $200.00

K $300.00


The use of gas welding dates back to the middle 1800's where a mixture of Oxygen And Hydrogen were used to produce a hot flame that was used in the making of jewelry. It wasn't until the late 1890's when the gas Acetylene became available that gas welding developed into the process that we know today. Acetylene is a gas that is manufactured by mixing Calcium Carbide,( a by product of the electric furnace steel making process) with water. Acetylene when burned alone can produce a flame temperature of about 4000 deg. F. With the addition of Oxygen a flame temperature in excess of 6000 deg. F. can be achieved, making Acetylene ideal for welding and cutting. An Oxy-Acetylene outfit is portable, less expensive and more versatile than a electric welding set up. By using the proper tips, rods and fluxes, almost any metal can be welded, heated or cut using the Oxy-Acetylene process.

There are many components that make up the Oxy-Acetylene outfit such as cylinders, regulators, hoses etc. The following is a typical outfit listing each component with a brief description of each.


Oxygen and Acetylene are stored under pressure in steel cylinders . They are sized by the cuft. of either Oxygen or Acetylene that they hold.

Cylinders should be tested regularly with the date of the last test stamped on the top of the cylinder. Cylinders should always be secured and used in the upright position. When a cylinder is not being used, the valve cap should always be in place.


These cylinders are made of steel and are usually painted green. They range in size from less than 20 cuft. To over 300 cuft and contain compressed Oxygen at pressures that can be as high as 2200 psig. All cylinders have valves and ( except the small "R" tank ) are fitted with a screw on steel cap that protects the cylinder valve when the cylinder is not in use. If Oxygen comes into contact with oil or grease, it will burst into flame. Never use oil or grease on Oxygen cylinder valves or regulators. Make sure hands and gloves are free of oil and grease before handling cylinders. Crack open the cylinder valve then close it before installing the regulator to clear the valve of any dirt. With the regulator installed, always crack the cylinder valve open first, then open it fully. This will lessen the chance of recompression which is caused by high cylinder pressure entering the regulator, heating up and damaging the regulator.


These cylinders contain Acetylene under pressure, are painted black, ( small "B" and "MC" tanks can be gray, silver or red ) made of steel and have cylinder valves. They range in size from 10 to almost 400 cuft capacity. The cylinders contain a porous filler material which is wetted with acetone that allows the Acetylene to safely be contained in the cylinder at 250 psig. Always use an Acetylene cylinder in the up right position so you don't draw any of the acetone out of the tank. Only open the cylinder valve 1 to 1 1/2 turns, leaving the valve wrench on the valve in the event it has to be shut off quickly. Acetylene should never be used at a pressure that exceeds 15 psig as it becomes highly unstable which, depending on the condition, could cause it to decompose and explode. As with the Oxygen cylinder, make sure the cylinder valve is clean before installing the regulator.




With the pressure in a full Acetylene cylinder at 250 psig and a full Oxygen cylinder at 2200 psig, a way is needed to lower these cylinder pressures to desired working pressures for use in the torch. This is accomplished by using an adjustable pressure reducing regulator. The regulator will also maintain a steady working pressure as the cylinder pressure drops from use.