Rigor/Relevance
Framework
LESSON PLAN
Knowledge
Area and/or Course Introduction to Welding
Lesson Title Introduction to Oxygen/Acetylene (O/A)
Welding
6
5
4
3
2
1
No. Periods 1 (73-minute period)
C
D
Assimilation
_______
Adaptation
____X___
A
B
Acquisition
_______
Application
_______
1
2
3
4
Application
Teacher Goal(s):
1. Students will demonstrate how to safely set up an
(O/A) system, and ignite the welding torch
2. Students will practice creating O/A welds
Objectives:
The student will be able to (TSWBT). (Oregon Skill Set numbers in parentheses at the
end of the objective statement.)
1. Identify the set up process for an Oxygen/Acetylene welding torch (AG 10.02.01.04)
2. Demonstrate properly striking the welding torch (AG 10.02.01.04)
3. Select applications in a real-world setting where O/A welding would be used (CS.EF.02)
4. Create O/A welds using safety, correct techniques, and form (EL.HS.RE.08)
5. Demonstrate properly shutting down the O/A welding torch (CS.HS.02)
State Standards met by Objectives:
Subject
Strand
1. Agriculture
AG 10.02.01.04
2. CRLS
CS.EF.02
3. CRLS
CS.HS.02
4. English
EL.HS.RE.08
5. Power Science
and Technology
PST 04.04.07.c.
6. Power Science
and Technology
PST 04.04.07.b.
Eligible Content
Demonstrate the set up and adjustment of tools and
equipment
Select, apply, and maintain tools and technologies
appropriate for the workplace.
Listen attentively and summarize key elements of
verbal and non-verbal communication.
Understand, learn, and use new vocabulary that is
introduced and taught directly through
informational text, literary text, and instruction
across the subject areas.
Construct and/or repair metal structures and
equipment using welding fabrication procedures,
including those associated with SMAW, GMAW,
GTAW, fuel-oxygen and plasma arc torch methods.
Distinguish welding processes, positions, and
materials preparation.
Knowledge: 1=awareness; 2=comprehension; 3=application; 4=analysis; 5=synthesis; 6=evaluation
Application: 1=knowledge in one discipline; 2=apply knowledge in one discipline; 3=apply knowledge across disciplines; 4=apply knowledge to real-world predictable situations; 5=apply
knowledge to real-world unpredictable situations
5
Materials, Equipment, Audio-Visual Aids:
References:
1. Oxygen/Acetylene welding torch
http://www.artmetal.com/brambush/forum/
bramyak3/messages/9.html
2. Gloves
3. Welding face shield
4. Striker
5. Various metal
http://www.stanford.edu/group/prl/
documents/html/OAweld.htm
Anticipatory Set/Introduction/Motivation/Interest Approach:
Review Yesterday’s Lesson:
Yesterday we talked about using the arc welder to create welds. What do you guys think are
some differences between arc welding (SMAW) and O/A welding?
-
Electricity
Pulling the puddle opposed to pushing the metal
Speed
What are some of the similarities?
-
Angles
Safety
Set:
The teacher will begin the Introduction to O/A Welding lesson with a personal story about an
issue which arose during the O/A process.
As most of you know, the only piece of equipment which I have had students get hurt on is the
Oxygen/Acetylene welding torch. This particular issue arose because the student was not paying
attention to safety or his surroundings. At the beginning of the class I had announced not to use
one of the welding torches because the acetylene hose was leaking. I was working with some
students in the arc booth, and another student calmly said, “Mr. Sherman, Billy is on fire.” As I
turned around I noticed that Billy was not only on fire, but he had no idea it was happening.
(Q) Who can guess what I did? (A) Remained calm
(Q)Exactly right I remained calm and turned off which gas first? (A) Acetylene
The most important fact to remember about that story is to remain calm, but also to try and
diffuse a situation. I trust all of you guys will pay attention to daily safety instructions and
remember what to do during an emergency. Right?
Transition (Use Objective):
1. Identify the set up process for an Oxygen/Acetylene welding torch
2. Demonstrate properly striking the welding torch
3. Select applications in a real-world setting where O/A welding would be used
4. Create O/A welds using safety, correct techniques, and form
5. Demonstrate properly shutting down the O/A welding torch
Strategy – Includes Teacher
Activity, Student Activity,
Questions/Answers and
Objectives
Subject Matter Outline/Problem and Solution (Application
Points Lace in Throughout Lesson) (Modeling, Guided
Practice, and Content)
Objective #1
Setting up the O/A System
In a review of safety, the
teacher will ask questions
about O/A system.
First check over the condition of the equipment. Are the
cylinders chained to the cart (or to a wall)? Are the torch valves
closed? Are the hoses in good condition?
(Q) Why do we double check
to make sure the tanks are
secured to the cart?
Check that the adjusting screws on each regulator are loose.
Loose means turned out counterclockwise. This releases the
pressure on the diaphragm.
(A) Because we don’t want the
tanks falling over
Open up the acetylene cylinder valve slowly so that it is onehalf to one full turn open (one full twist of the wrist). The
needle on the high pressure gauge should now indicate the
amount of acetylene pressure in the cylinder. If no pressure is
indicated - stop at this point.
(Q) What can happen if the top
is sheared off of the tank?
(A) Rocket
Screw in the adjusting screw on the acetylene regulator
(clockwise) until the needle on the low pressure gauge
(Q) What is the pressure where indicates the desired working pressure. The working pressure
acetylene becomes unstable?
depends on the torch tip size.
(A) 15 p.s.i.
The teacher will then ask the
students to help with the set up
of the O/A system. Questions
are designed to get students
thinking about why we turn the
O/A system on in a certain
manner.
Now bleed out the acetylene hose and check the actual working
pressure at the same time. To do this, open up the acetylene
valve on the torch. Let the gas flow out of the torch for a few
seconds. While the torch valve is still open, look at the low
pressure gauge and readjust to the desired working pressure.
Close the torch valve.
Open up the oxygen cylinder valve stem just a crack. Once the
needle on the high pressure gauge has stopped, open up the
valve all the way. This back-seats the valve. Oxygen cylinders
(Q) Why is the oxygen tank
must have the valve opened up all the way because of the high
valve opened all the way, but
pressure in the cylinder. There is a back-seating valve on the
the acetylene only opened ¼ of oxygen cylinder. This prevents the high pressure gas from
a turn?
leaking out through the threaded stem.
(A) So we can more easily turn Screw in the adjusting screw on the oxygen regulator
the acetylene tank off if
(clockwise) until the needle on the low pressure gauge
needed.
indicates the desired working pressure. Note that this gauge is
usually calibrated in 5-pound increments, differing from the
(Q) There are two pressure
acetylene regulator low pressure gauge.
indicators on each tank; what
are their purposes?
(A) The one on the right is
usually tank pressure and the
pressure valve is on the left is
for line pressure.
Now check the actual working pressure of the oxygen in the
same way as was done for the acetylene. If you screw it in too
far and obtain too much pressure, be sure to open the torch
valve before readjusting the pressure.
Objective #2
Striking the Welding Torch
(Q) Why do we only open the
acetylene valve a little bit
RIGHT before we are ready to
strike?
Open the acetylene torch valve about one-quarter turn. Light
the acetylene with a spark from a "striker". Do not use matches
or a butane lighter.
(A) So we do not have an
explosion with too much
acetylene
(Q) Should there be any
oxygen in the mix when we
are lighting the torch?
(A) No, we do not add oxygen
until we have an acetylene
flame properly adjusted
(Q) After we have lighted the
acetylene; what do we want
our flame to look like?
Adjust the flame, using the acetylene torch valve until the
flame has just lost its "smoky" quality. If the flame "blows out"
or blows away from the tip of the torch, the valve is too far
open. If the flame jumps away from the torch tip, you have it
too far open. Close the valve a bit and then slowly reopen.
With the proper shade gas welding lens over your eyes (#4-7),
slowly open up the oxygen torch valve. A small, pointy flame
very close to the torch tip will appear. This is called the
�inner cone'. At the same time, a distinct, blue flame will
begin to appear at the end of the flame. Continue to slowly
open up the oxygen torch valve until the distinct blue flame has
just shrunk to the same size as the inner cone. This is the proper
welding flame called a neutral flame.
(A) No black smoke, but the
tip of the flame is just
feathering
Objective #3
What are the Applications of O/A Welding?
Before the students begin
actually welding with the O/A
system, the teacher will discuss
with the students some of the
practical applications of using
oxyacetylene welding.
However, it is still widely used for welding pipes and tubes, as
well as repair work. It is also frequently well-suited, and
favored, for fabricating some types of metal-based artwork.
Oxyfuel equipment is versatile, lending itself not only to some
sorts of iron or steel welding but also to brazing, brazewelding, metal heating (for bending and forming), and also
oxyfuel cutting.
(Q) Has anyone in the class
every used oxyacetylene for
welding?
In oxy-fuel welding, a welding torch is used to weld metals.
Welding metal results when two pieces are heated to a
(Q) What are some
applications where O/A
welding could be used?
temperature that produces a shared pool of molten metal. The
molten pool is generally supplied with additional metal called
filler. Filler material depends upon the metals to be welded.
(A) Welding pipes, brazing, at- Advantages of Oxy-Acetylene Welding :
home uses, etc.
 The equipment is cheaper than most other types of welding
(Q) What are some of the
rigs (e.g. TIG welding)
advantages of oxyacetylene
welding over many other
 The equipment is more portable than most other types of
types?
welding rigs (e.g. TIG welding)
(A) Easy to learn, equipment is  OA equipment can also be used to "flame-cut" large pieces
mostly portable, can be used to
of material.
cut as well with the proper tip
Disadvantages of Oxy-Acetylene Welding :
(Q) What could some of the
disadvantages be?
 OA weld lines are much rougher in appearance than other
kinds of welds, and require more finishing if neatness is
required.
(A) Rougher in appearance due
to the heated zones

OA welds have large heat affected zones (areas around the
weld line that have had their mechanical properties
adversely affected by the welding process)
Objective #4
Creating O/A Welds
The teacher will demonstrate
how to make O/A welds using
the welding torch, and then
after asking and answering
questions the students will be
able to start practicing safe
and effective methods of
creating oxyacetylene welds.
1) Put on a dark face shield to protect your eyes from the light
of the flame. Make sure you have on long sleeves and all
natural fibers. You can wear a leather welding jacket
and/or gloves if it makes you feel more comfortable.
(Q) When we are oxyacetylene
welding, are we pushing or
pulling the metal?
(A) pushing
(Q) Why do we only move the
puddle in one direction?
(A) The gases coming out of
the welding torch will help to
2) Apply the flame to the parts to begin heating. Use the
region of the flame near the tip of the bluish inner region.
3) The metal will begin to glow. Continue heating both parts
being welded until a small pool of welded metal appears
near the edge of each of the parts. You must get molten
pools on BOTH parts simultaneously to create the weld.
The may require adding more heat to one side than the
other, and takes some practice.
4) After the molten pools have formed on both sides of the
weld, use the flame to gently stir the two pools together to
form the weld. This also takes a little practice.
5) After the two pools have joined, slowly move the flame
move the puddle across the
metal and heat the metal
before our puddle gets there
(Q) How do you know when
you have a puddle?
(A) The metal will get red, and
then all of the sudden the
puddle will appear.
The teacher will ask students
to put their face shields on
watch for the puddle to form,
asking the students to say
“now” when the puddle forms
along the weld line, lengthening the pool using metal from
both parts. A gentle, circular, swirling motion will help
mix the molten metal from both sides as the puddle is
lengthened. This process is highly dependent on the
materials and part geometries being welded. Practice,
practice, practice to get better control. Welding sample
parts is a good idea.
6) Continue this process until the entire weld line is complete.
7) Once you're done, turn off the flame. Close the oxygen pin
valve first, and then the acetylene valve. Note: Welded
parts can remain hot for a LONG time.
Backfiring
Improper operation of the torch may cause the flame to go out
with a loud snap or pop. This is called backfire. It is caused by
one of a few things. The first thing to do is turn the gas in the
torch off, check all the connections and try relighting the torch.
(A) Something is wrong with
Backfiring can be caused by touching the tip against your work
our operation of the torch or an piece, overheating the tip, operating the torch at other than
incorrect mixture of gases is
recommended gas pressures, by a loose tip or head or by dirt on
being used.
the seat.
(Q) What is happening when
we hear the torch pop?
Objective #5
Shutting down the O/A System
The teacher will demonstrate
the proper method to shut the
set up down, and ask students
to write down the steps for set
up and shut down of the torch
to reference if needed.
Proper shut-down of the cylinders
The students will turn in the
start up and shut down sheets
to the teacher for a grade.
(Q) The acetylene was the last
tank we opened and the
______ one we turn off?
(A) first
(Q) How hard do we have to
turn the valves on the system?
Extinguish the flame by turning off the acetylene torch valve
first. Then turn off the oxygen torch valve. Close them gently
because they are needle-valve and their seats can be easily
damaged. It is important to do the acetylene first and then the
oxygen. If the reverse order is used, carbon deposits are left in
the torch every time the torch is turned off. For very large torch
tips, some people turn the torch off in the incorrect manner
because of the loud pop the torch sometimes makes.
Close the acetylene cylinder valve with a firm hand. Close it to
the right (clockwise).
Open the acetylene torch valve again. Watch the needles on
both of the acetylene cylinder gauges. When they are both at
zero, gently close the torch valve again. The acetylene has now
been properly bled from the system.
Close the oxygen cylinder valve. Since this valve was
(A) Just turn until it closes do
not turn too tight
previously opened up all the way, it takes some time to get the
valve fully closed. Close with a firm hand.
(Q) Why do we drain the hoses Open the oxygen torch valve. Watch the needles on the oxygen
and pressure valves?
regulator valves. When both of the valves are at zero, close the
torch valve again. The oxygen has now been properly bled
(A) To decrease the chance for from the system.
an accident with the gases
Wrap the hoses around the handle part of the cart. If the torch
(Q) Why is it important to get
tip is still hot, be careful that it does not touch any part of the
all of the hoses wrapped back
hoses. Don't wrap the hoses around the cylinders. If the hoses
up?
are around the cylinders, it is not easy to tell if the cylinders are
properly chained.
(A) So we do not have the
chance of people tripping over Note: The cylinders should be completely shut down in this
the hoses
manner when you are done using the equipment for the day. If
you are the last person in the area that work day, be sure to
(Q) How do we know when
check that other cylinders are shut down properly. If you come
the shut down is complete?
upon cylinders that are not shut down properly, first screw in
the adjusting screw until the low pressure side of that regulator
(A)
indicates pressure. The open up the corresponding torch valve
1. The hoses are wound up
and wait until the needles drop to zero. Then loosen the
2. The pressures are bled off
adjusting screw again. Sometimes this happens if the cylinder
3. Regulator valves are lose
valve stem was not closed tightly enough - check that too.
4. Tank valves are closed
Closure/Summary/Conclusion (Tie in Objectives)
How do we know when the shut down is complete?
1. The hoses are wound up
2. The pressures are bled off
3. Regulator valves are lose
4. Tank valves are closed
What have we learned today?
1. Identify the set up process for an Oxygen/Acetylene welding torch
2. Demonstrate properly striking the welding torch
3. Select applications in a real-world setting where O/A welding would be used
4. Create O/A welds using safety, correct techniques, and form
5. Demonstrate properly shutting down the O/A welding torch
Evaluation: (Authentic forms of Evaluation, Quizzes, or Written Exam)
Visual and verbal checks for understanding will be done by the teacher to ensure the students are
understanding the concepts of O/A welding and striking the torch
Self-evaluation
Assignments: (Student Activities Involved in Lesson/Designed to Meet Objectives)
Daily calendar
Self-evaluation
Set up and shut down procedural check sheet
Lesson Reflection
This lesson is more complex than I had originally thought. Students seemed to have a hard time
articulating back to me the procedures of starting the system and shutting it down. Having the
students write down the instructions seemed to help the process, and students were able to have
that piece of paper to reference for future use. If I could do the lesson over again I would spend
extra time having each student start up and shut down the system in front of their peers and if
they were struggling I would allow the class to help them through the process.