Introduction to

Oxy-Acetylene Welding

Welcome to the Columbus Metal Shop!

spark!

The metal shop facilities include a wide range of hot and cold metal working equipment.

The School of the Art Institute’s Columbus Metal Shop is one

of four Instructional Fabrication shops at SAIC.

The Columbus

Metal Shop is a

general access

facility set up to

provide

instruction and

material

resources for the

School’s

students, faculty,

and staff.

The Metal

Shop’s

facilities and

unique

instructional

programs

have been

structured to

meet the

needs of

students

working on a

wide range of

projects.

INSTRUCTIONALFABRICATION

Instructional

Fabrication’s mission is

to serve the

contemporary art making

needs of the School of

the Art Institute of

Chicago by providing

instruction and technical

assistance to students

and faculty using the

School’

s shops

and

fabricati

on

facilities

. Our

staff

work

collabor

atively

across

artistic

and

academ

ic

disciplin

es to

support

all

manner

s of

fabricati

ng art

objects

.

Instructional Fabrication is a division within the department of Instructional Resources & Facilities Mana

ge

Cold workingcapabilities include

• drilling• punching• mechanical fastening• roll forming• bending

• shearing

• cutting

• grinding

• sanding

• abrasive blasting

Instructional Fabrication

Table of Contents

6 GettingReady

8 Equipment forProces

s :Check

OutFromCage

10 Mat

erialConcerns

11 Mat

erialHandling

12 WeldingAnatomy & Capability

14 Turningon Fuel

16 Turning on Fue

l continued

18 Process

: Welding

20 Process

: Cutting

22 ClosingDown

: Leaving Station

Introductionto

Oxy-Acet

ylene WeldingOxy-Acetylene, commonly known as Oxy-fuel, is one of the oldest welding processes, though inrecent years, it has become less popular inindu

strialapplications. However,it is still widely usedfor avariety of applications. Oxy-fuel equipment is versatile,lending itselfto welding, brazing, braze-welding, silver soldering, metal heating (for bending and

forming) and oxy-fuel cutting.

This bookwill highlight the weldi

ng and cutting processes.

4 |The School of the Art Institute ofChicag

oInstructional Fabricatio

n |5

G

Authorizations

In order to work in the Metal Shop,you must first attend an Authorization. Authorization Sign Up Sheets and Authorization Request Forms are posted adjacent to the tool checkout area in the Columbus Wood Shop,Room 024. It is highly recommended that new patrons complete the Introduction to Metal Working Authorization before participatingin the welding authorizations.

Planning Your Project

(See also Material Concerns,page 10)

We encourage patrons to speakwith the shop’s staff about making material choices that bestsuit yourprojects before committing to a purchase—your choice ofmaterials may limit what equipment will beavailableto you.

Flammable Combustibles Prohibited

Flammable Liquids are prohibited inthe Metal Shop, including but not limited to butane lighters, propane, aerosol cans, and solvents. Use extreme caution when working near flammable materials (sketchbooks, backpacks, etcetera). Flames, sparks, and hot surfacescan cause fires.

A

P

St

wi

A

Re

H

Ti

S

Ch

P

Ch

Cu

S

St

Instructional

Fabrication | 7

E

Overview

Eye Protection

Welding Jacket

Hand Protection

Hearing Protection

RE

We

Welding Gloves

Striker

RE

Ear Muffs

We

g Jacket

Welding Tip orCuttingAttachment

Filler Material

Magnetic Clamps& Fixtures

Respiratory Protection A Welding Fume Respirator

l a

ghammer

Welding FumeRespirator

Material Concerns MaterialMaterialHandlingHandling

The Columbus Metal Shop sells steel in a variety of shapes and dimensions. Rod stock and tubing is available in rounds and squares, angle iron is availablein a variety of dimensions, and sheet metal is available in common gauges (thickness).

Linear material is sold by the foot length or in some cases full lengths averaging 12 feet. Sheet metal is soldby the square foot, with a minimum purchase requirement of 4 square feet (24” X 24”).

Types of Steel

Hot Rolled

1• Grayscale on surface

2• Clean withwire brushbeforewelding

Cold Rolled

How to CarryA separate pair of gloves for material handling is recommended—DO NOTuse Welding Gloves. Also, it is very important for your welding gloves toremain oil-free.

Use caution when entering & exiting doorways or blind intersections.

Do not try to carry long lengths or heavy material without help. Avoid walking in front ofor behindmaterials, walk

alongside.

1• Shiny, oily surface

2• Clean with orange soapand paper towels before welding.Dispose of paper in red fire-proofcan.

Beforewelding,make sureto removeall oil used

during t

hepreparationandfabrication ofmaterials.

Ke

ri

DO NOT weld on materials, including hardware, that contain:

• Paint

• Wax• Chrome Plated or

Galvanized Surfaces• Magnesium

Reuse Bin Recycle BinMaterial for the Reuse Bin must Please refrain from tossing

be approved by management. unusable material, recycle it.

10 | The School of the ArtInstitute of Chicago

Instructional

Fabrication | 11

Welding: Anatomy & Capability

A. Mixer

There are8 mixingstationsattachedto thewall. Thisis yoursource foroxygenandacetylenefuel.

Torch Head

Barrel

CThe cutting attachment simply functions as a

convenientand economicalapproach to cutting st

eel. The cutting attachment can be used for material up to 3/4

of an i

nch thi

ck.

The mixer is where you will attach welding tips, cutting attachment, and the rosebud heating torch.

Oxygen Control Valve

AcetyleneControlValve

Acetylene Hose (red)

Oxygen Hose (green)

Mixing Chamber

Control Valve

Close up ofOxygen Control AttachmentCutting Attachment

B. Welding Tips

There are 3 types of welding t

ips available: 1, 3, 5, and 9. Tipsize will depend ontype of filler material used,see below chart.

Rosebud is a fuelintensive attachment thatshould be used withdiscretion. Pleasecheck withshop staffto seeif it might be right foryour project.

REGULATOR SETTINGS

Material Tip Size Acetylene Oxygen Filler Rod

22-18 gauge 1 8 psi 8 psi 1/16"

16-14 gauge 3 8 psi 8 psi 3/32"

12-10 gauge 5 8 psi 8 psi 1/8" Close up ofRosebud Heating Tip

1/4"-3/8" 9 8 psi 8 psi 3/16" *

* 3/16" filler rod is not available through Resale.

1 3 5 9

12 | The School of the Art Institute of Chicago Instructional Fabrication | 13

TurningOn Fuel

1.

Before you begin,perform HoverTest.

Place the back ofyo

ur barehandclosetoaworksurfaceor tool befor

e touching orsetting down something heatsensitive.

Weldingtables,stationaryequipment,tools,andscrapmate

rialmightnotappearhot,butmay be hotenough to injur

eyouordamageequipment.

2.

Take enough hose off hanger carefully

sothemixer rea

ches the welding table withoutcreating a tripping ha

zard.

3. Inspect the hose for wear or damage bymaking your way from the torch handle to

theregulators.

4. Install tip into mixer, handtighten nut on top with touch tip facing to the left (for right handuse) or facing right (for left-handuse).

AB

5. Check torchhandle to makesure it is closed by gentlyturnin

g knobs counter clockwise to openand then clockwise to completely close.

AB

6. Check regulator keys to make sure they are backed out (disengaged) and approximately ½ inch

of threads are exposed.

approximately ½ inch

14

Turning On Fuel continued

7. Standing to the side of regulators, acetylene shut-off valves slowly by turning counter-clockwise until

fully opened, then close

A

9. Before the torch is lit, put on welding gloves and oxygen-acetylene goggles.

Open:Counter-clockwise

Close½turn:Clockwise

8. Open acetylene while directing welding tip towards exhaust. Turn regulator key

800

60

0

120100

80

040 60

40

20

200

1000

0

1601200

180

200

600 800

clockwiseuntil 5 psi registers onregulatorgauge, always reading in red. Then close mixer valve.

4

200

80

100 120 1000

160

1200

180NO OIL

200psi

00kPa14

Ratio 1:1

1 partacetylene to 1

800

60

00

100 12

80

060

40

40

20

200

Ac

Process:Welding

Light theTorch1. Direct

torchaway fromyou,towardstheventilation.

2. Openacetylenecontrolvalve onmixer,approximately 1/8 turn rotation counter-clockwise.

spark!

3. Light with striker. Neve

r use lighters or other sources for ignition.

2* Always position yourself with fre

sh air at your back so fumes are drawn away from you, not past you.

Adjust the Flame

4. Adjust acetylene to form feather shaped flame.

If there is too much acetylene, flame breaks awayfrom the tip. Slowly add oxygen—flame will sharpen andelongate.

Continue to add oxygen

until neutral flameis established.

And Weld!5. Focus

greencone's tip(neutralflame)onto areayou arewelding.

6. Maintainaconsistentdistancefrommaterial,heating anarrowpathbetweentwomaterials.

7. Afterpuddle isestablished,introducefiller rod.

8. Meltfillerrodintopuddleandmovealong,establishing

a weld path,often called a bead.

Weld Path

Flame Tip

ofWeld — Direction <

Welding Tip

Filler Rod

18 |TheSchool of theArtInstituteof Chicag

oInstructional Fabrication

| 19

Process: Cutting

A. Prepare Equipment

1. Inspectcuttingattachmentsbeforeuse.Ifthereappears tobegrease, oil,orequipmentdamage,returntoolsto thecageandexchangefor aworkingreplacement.

2. Insertcuttingattachmentintothetorchhandleandhandtightentheconnectionnut.

3. Adjust oxygenregulator to thepressure settingrelative tomaterialsize, seetip chartbelow.Thenopenoxygenvalve on

torchhandle.

4. Adjustacetyleneregulatorto 10psi.Thenopenacetylenevalveontorchhandle.

REGULATOR SETTINGS

Material Cutting Tip Size

Up to 10 gauge

Up to 3/16"

Up to 1/4"

Up to 3/8"

Up to 1/2"

Up to 5/8"

B. Ignite Flame

1. Openacetylene valve

on torch 1/8 turn

and light withstriker.

2. Openoxygenvalveandflameshouldappear,also

knownasacetylenefeather.Continuetoaddoxygenandreducefeatheruntilneutralflameisestablished.

3. Est

ablish puddle by maintaining a consistentdistance from ma

terial,heatinganarrow path(sameaswelding).

4. Depressoxygenlever andmove tomake cut.

Cutting AttachmentWeld Cut

Direction of Cut —>

Flame

Oxygen Lever

NOTES: Material must be supported and cut with the grain of the table, never against.

Keep feet and hose from underthe table and away from fallingmetal debris.

2

0 | The Scho

ol of the Art Institute of Chicago

Instructional Fabrication |21

Closing Down: Leaving Station

1. Extinguish flame by first closing oxygen at mixer.Turn torch handle knob counter-clockwise. Repeat

process toclose acetylene at mixer.

A Oxygen first,

2. Close shut-off valves turning clockwise.

Close: Clockwise

3. Bleed the line. Open acetylene at mixer and allow fuel toempty for a few seconds, a process known as bleeding the

line. Then

closeacetylene at

mixer.Repeat for

oxygen.

A

Acetylene

first, Bthen oxygen.

4. Back out regulator keys regulators, exposing approximately

5.

approximately ½ inch

Take tip off, be careful of temperature. Allow tip orattachment to cool before returning to cage!

HOT!

6. Hang hose up on wall rack in large, neat loops. Returnall the equipment back to the cage.

22 |

The School of the Art Institute of

Chicago Instructional Fabrication | 23

End Comments

Please do not hesitate to ask for help. If you are not absolutely certainabout what you are doing, or if you are having difficulty with anyaspect of the process we can help.

If the equipment is not working properly or appears to be damaged stop immediately and seek shop staff.

General Principles in Welding Steel

A well balanced neutral flame is used for welding most steels. To be sure the flame is not oxidizing, it is sometimes used with a

slight acetylene feather. A very slight excess of acetylene may be used for welding alloys with a high carbon, chromium, or nickel content. However, increased welding speeds are possible by using a slightly reduced flame. Avoid excessive gas pressure because

it gives a harsh flame. This often results in cold shuts or laps, and makes molten metal control difficult.

The tip size and volume of flame used should be sufficient to reduce the metal to a fully molten state and to produce complete joint penetration. Care should be taken to avoid the formation of molten metal drip heads from the bottom of the joint. The flame should bring joint edges to the fusion point ahead of the puddle as the weld progresses.

The pool of the molten metal should progress evenly down the seam as the weld is being made.

The inner cone tip of the flame should not be permitted to come in contactwith the welding rod, molten puddle, or base metal. The flame should be manipulated so that the molten metal is protected from the atmosphere bythe envelope or outer flame.

The end of the welding rod should be melted by placing it in the puddle under the protection of the enveloping flame. The rod should not be melted above the puddle and allowed to drip into it.

INSTRUCTIONALFABRICATION