1. Arc Welding SMAW
Shielded Metal Arc Welding (SMAW). Electricity, as it jumps a gaseous gap between two conductors.
Produces an arc as intense as 9000.
Arc welding is an electric welding process. Electricity flows through two cables, one positive and one negative, and when these cables meet an electric arc jumps between the two. This is like a set of jumper cables on steroids. When you hook the cables up to your car and then touch them together you get sparks, with an arc welder you get an arc that can be as intense as 9000°
Start up a welder and strike an arc, so that the students can see the sparks.

2. I. Types of Welders Rectifier
D.C. (Direct Current) Electricity is converted from A.C (Alternating Current) through transformers and rectifiers.
A.C./D.C dual purpose.
There are other types of welders like transformers and engine driven generators, however the ones that we will use are called rectifiers. Engine driven welders are the ones that you would see in the back of a truck they run off of gas or diesel and produce electricity just like your car does.
Rectifying welders change the electricity in the wall from AC to DC and allow us to work in both fields. We will talk more about the difference between AC and DC later on.
The pictures you see are of the amperage control. The amperage controls how hot the arc becomes. You can see that there are four circles drawn on the control. We will be using the black circle on the ring that says DC 35 – 155.

3. II. Electrodes Lengths – usually 14”
Diameters – 3/32”, 1/8”, and 5/32” are most common
Classification – Brand names differ but the A.W.S (American Welding Society) number system is the standard.
Electrodes come in many different sizes and lengths, however most of the common ones are 14” long. Thicker electrodes require more amperage to run and weld on thicker metals.
AWS stands for the American Welding Society. They classify all electrodes and their uses through a number system printed on the electrode.

4. Electrode classification ex. E 6 0 1 3 “sixty thirteen”
E = Electrode
60 = Tensile strength of deposited weld metal times 1000 p.s.i.
1 = Rod position (1=all, =horizontal or flat, 3=flat only)
3 = Dealer characteristics
(Dealer characteristics are things like polarity, application, flux composition.)
The electrode classification is a four to five digit number printed on the end of the electrode with the bare wire showing. (Pass out example electrodes) These electrodes are for you to see, they are not drumsticks or weapons so please be mature with them. There are many different types of electrodes, the two on the screen are the sixty thirteen and the seventy eighteen.
Explain the electrode code. E is no longer printed on most electrodes. The first two to three numbers stand for the tensile strength x Tensile strength is the amount of force that it would take to pull the weld apart from either end.
The third # is the rod position. Some electrodes can only be used on a flat weld. If you use them to weld overhead, the hot metal will drip down onto you.
Last we have the dealer characteristics. These are things that are added to the electrode to make it use a certain type of electricity or to add something to the weld.

5. Five functions of flux or slag
Flux is the powder on the electrode, slag is the brown deposit left on the weld that must be chipped off.
Cleans the metal of oxides
Stabilizes the arc
Keeps oxygen away
Forms the weld
Lets the weld cool slowly
Flux and slag are like ice and water. They start out as the same thing and end up in different forms.
When the powder is on the electrode it is known as flux, it then burns off as you weld and does three things for you. The smoke keeps oxygen away from the weld since oxygen rusts metal, the smoke travels into the liquid metal and brings all of the impurities to the surface and it also helps to focus the arc into one location.
When the metal starts to cool the flux powder floats to the surface of the weld and becomes slag. The slag is a hard brown coating that helps the weld cool slowly and helps to form the weld. The slag must be chipped off with a slag hammer in order to see the finished weld.

6. Ruler quiz. Fill in the fraction. 16th scale.8 4 12 6 14 2 10 1 3 5 7 9 13 11 15
Either draw a ruler and label the lines or number your paper from 1-15 and write in the correct answers.

7. Polarities
Polarity is a type of electricity, we deal with three types. DC positive, DC negative and AC. Next we are going to talk about each.

8. Direct Current Electrode Negative. (D.C.E.N)
Also known as DCSP or Direct Current Straight Polarity.
Electricity moves from negative electrode to positive work table.
1/3 of the heat at the electrode, good for thin metals
Prone to arc blow
DC negative means that the electrode holder is connected to the negative terminal on the battery and that the work lead is attached to the positive side. This gives us less heat at the electrode which lets us weld on thin metals. We will not use DC negative in this class.

9. Direct current Electrode Positive (D.C.E.P)
Also known as DCRP; flows in one direction also, (-to+) but the leads are reversed
1/3 of the heat at the base metal and 2/3 at the electrode.
Deep penetration – good for thick metals
Prone to arc blow.
This is the polarity that we will use most often. The electrode holder is now positive and the work lead is negative. This gives us much more heat at the electrode which in turn allows us to weld on thicker plates.

10. Alternating Current (A.C)
Electricity that moves from positive to negative so often that there is no polarity.
This has several advantages:
More economical
Uses most all rods
No arc blow
Alternating current is the power that is in the wall already. To get DC power we have to adjust the AC wave. (Draw chart of AC sin wave crossing positive and negative grid.) To make DC power we have to overlay several positive or negative sin waves to over balance the AC.

11. Striking the arc.
Like striking a match, touch the electrode to the metal and strike. When the arc appears, hold for a second and then drop the electrode down to the metal.
Motion – For the welds you are doing, there is no motion. Simply drag the rod in a straight line.
(Demo striking the arc again with the machine off and then on, tell the students to watch their eyes)
Discuss the slide

12. Weld Joints
Welding joints are different ways to line up the metal to attach them. They are not the joints in the car, puff, puff pass.

13. But joint.
Prepare the joint. The metal must be clean. Always tack and V thick pieces for penetration.
In both oxy-acet and arc welding, gap the pieces for penetration.
Most simple joint you are butting up one piece of metal to another. Either leave a small gap between the plates or grind a bevel onto both edges to allow the weld to burn all the way through. This step is important. If you gap the pieces too far, you will burn a hole through the plate. If you don’t gap them enough the weld will not get enough penetration and will be weak or stand too tall. 1/16”- 1/8” is what we are looking for.

14. Flange (edge joint) This is one of the easiest welds.
This weld is done with no filler rod in oxy-acet welding.
This weld is simple for several reasons. First it forces you to follow a straight line. In oxy welding there is no filler metal added so the pieces are simply fused together with the torch.

15. Lap Joint
Very common weld. The plug, rosette, and slot weld are all variations of the lap weld.
In oxy-acet and arc, concentrate the majority of heat at the bottom plate and wait to fill in to the top.
A lap weld is a stronger version of a butt weld. Instead of merely butting the two pieces together, we are now overlapping them. Now the metal is twice as thick at the joint which should give double the strength.
Angle the rod into the joint at 45 to 60° and then angle in the direction of travel 20°. This compound angle (hold an electrode at the proper angle for the students to see) will give us the best weld build up and will push the slag behind you and not let it fall in front of the weld.

16. Inside corner (T joint)
This weld is very similar to a lap weld.
Concentrate the majority of heat on the bottom plate.
The same angle is held for and inside corner. This weld can be tricky to master, so you will want to practice it several times before you do one for your project.

17. Outside Joint This weld is done without filler rod in oxy-acet.
In arc welding try to allow for a natural V.
The important part to this weld is the set up. There are several ways that we could set up this weld to achieve full penetration, we could use a grinder to bevel the pieces or put grooves in the pieces or we can set up a natural bevel groove by aligning the pieces edge to edge before we weld. This setup allows for full penetration in the weld and a nice crowned appearance when finished.

18. Ruler quiz. Fill in the fraction. 16th scale.8 4 12 6 14 2 10 1 3 5 7 9 13 11 15
Either draw a ruler and label the lines or number your paper from 1-15 and write in the correct answers.

19. Welding Positions FLAT HORIZONTAL VERTICAL OVERHEAD
There are four welding positions, we however will only be working with two of them in metals I. The flat and horizontal positions are the ones that we will see. Vertical and overhead welds are not only difficult but dangerous and will not be dealt with until Metals II or III.

20. ROD POSITION
Flat – Rod perpendicular to base metal. Incline about 20 from perpendicular toward direction of travel. Drag the weld. (Backhand)
In a flat weld the correct torch tip angle is 20° from perpendicular. As the picture shows we want to drop the electrode down in the direction of travel, for right handers this will be from the right to the left and the opposite for lefties. Backhand is dragging the puddle, this is the most effective technique in arc welding.

21. Lap or Inside Corner – Angle rod 30 to 45 to base metal
Lap or Inside Corner – Angle rod 30 to 45 to base metal. Incline 20 toward direction of travel. Drag weld.
Lap and inside corner welds are considered horizontal since the deal in two planes. We have already discussed the correct angle for this weld but the pictures here give a good representation.

22. Problems
Here we have some pictures of good and bad welds. Bad welds are caused by several factors. Too much or too little heat, too fast or slow travel speed and the length of the arc all come into play at this point.
Heat is not only determined by your amperage settings on the machine but also by the length of the arc from the end of the electrode to the plate. The longer the arc the hotter the weld. By having your amperage too high or your arc length too long, you add more heat to the weld and it will spread out and cause excessive splatter as shown in these pictures. (Point out pictures)
Conversely, having the electrode touch the plate or having too low a heat setting will form a very narrow bead that may not penetrate through the metal.
Travel speed also affects the weld. Traveling too fast or not at a constant speed, fast then slow, will form a weld only on the surface of the metal that will not look very nice and will be very weak. Traveling too slow puts too much heat into the metal and causes the weld to widen.

23. Arc Blow A magnetic force that deflects the weld into splitting.
This is only a problem on DC polarities.
To cure, reestablish the ground or shorten the arc length.
Arc blow is not as big a show as it sounds. The weld does not explode or blow apart. Most times you will see a crack in the weld right behind the weld puddle that will follow all the way to the end. A long arc or bad work lead connection could be the cause.

24. Undercut A trough or erosion cut on either side of the weld.
To cure this, turn down the amps, shorten arc length or hesitate at the edges to allow for fill in.
From the picture you can see the gouges on either side of the weld bead. This is known as undercut. We are looking at this weld from the end and you can see how it didn’t quite fill in. This will be one of the major points that I will grade you on in arc welding. Slow down, and let the weld bead fill in or up to the level that you want in a weld joint.

25. Rod sticks
Break the circuit or current flow by releasing the electrode from the electrode holder.
Break the rod free from the metal with a gloved hand and start again.
This can be avoided by turning the amps up, not touching down to the metal or by using the correct electrode.
Extremely common. The electrodes that you will use, the sixty-thirteen electrode is much less likely to stick than a seventy-eighteen. This will hopefully help you to start out and give you the confidence to weld. The rod can stick for other reasons as well, check the amperage on the machine we should be between 105 and 115 amps. Next check that the electrode holder is gripping the electrode only on the bare metal end. Finally check for any slag on the tip of the electrode that may look like brown glass. This must be broken off by tapping the electrode on the metal.

26. Arc won’t start Check the following: Machine set up and switches.
Check the ground.
Check the rod, is it in the stinger correctly and is the end of the rod glassed over.
This also happens quite often, so before you run to me make sure that you check the following.

27. Welds The weld may split. Go slower to let the metal fill in.
Excessive spatter, check the electrode height.

28. Safety
This is all of the gear that we will have to wear to safely operate this equipment. Anyone welding without this equipment will be punished accordingly.

29. Protective equipment
All of the following equipment protects you from heat, splatter and harmful rays (ultra violet and infrared).
Gloves – leather. Do not handle hot metal or get them wet. Leather will burn, shrink and harden.
Jacket – leather. Not to be used as a shop coat. For welding only.
Helmet – a full head and face shield. Headgear can be adjusted. The lenses are #10-12 filter plate.
Be respectful to the equipment you are given. Many times our glove get holes in them due to students grabbing hot metal without using plyers or vice grips. Make sure you are following safety guidelines.

30. Never Expose skin or eyes to flash or arc.
Change the amperage setting while the machine is under a load.
Chip slag without eye and face protection.
Get your gloves wet.
Exceed the work limits. The duty cycle of the machine is a ten-minute span. It is the amount of time out of ten minutes that you can weld continuously. Ex. 70% = 7 out of 10 minutes.