Note to those following along: I edited lesson seven. Be sure to go back and re-read it. The changes are in orange to show where the changes were made, not to add extra importance.

 

Even tho i dont use a MIG, i have been reading these tutorials too, and they are great Ax.
Are you going to be doing similiar on TIG welding? Theres ALWAYS more to learn, and so many different ways to do things that i just thought i would ask.... John

 

I'm with lexcoe no matter how good we think we are a guy can always be better . One question for you ,my off shore mig packed it in so I replaced it with a Hobart Handler 190 . What's your opinion of that unit ,I figured 649.00 was a pretty good buy for around here.

 

I don't do enough TIG welding to feel comfortable giving lessons presently.
I am toying with buying one of the Eastwood TIG units.
The Hobart Handler 190 is a good unit, It was the unit I taught classes with. I have it's 115V baby brother, the HH 140.

 

sounds good.

 

GOOD GRIEF bumped to page 7! Write to the management if you think this info is important enough to be a sticky!



Lesson 8: Let's stick together!
Joining two pieces of metal together is what welding is all about, so it's time to learn how it's done. I will assume that by now you have been running enough practice beads on 16 ga metal to get comfortable with your welder and find the settings that give you a consistent bead ~ 1/4” wide with full but not excessive penetration. If not, what are you waiting for? No one is a born certified welder, we all need to practice and experiment to get consistent. I always run a few practice beads on similar material before welding something critical, no different than an athlete warming up and stretching before competing. You need to get the muscle memory freshened and mentally ready to concentrate, as well as making sure your equipment is working properly.


In this lesson we will first learn to make butt joints, the most common and basic weld. We will make them in medium weight metal first then in the next lesson learn what needs to be changed when working with thinner metal. As in learning to run a bead we will work with 16 ga sheet stock about 3" x6”. If at all possible get a fab shop to shear you a dozen or more pieces from cold or hot rolled sheet stock so you have nice straight edges to work with. If you need to cut your own, try to keep at least one long edge on each piece as straight as possible and the pieces flat. If you are using hot rolled stock, sand off the oxide coating for at least an inch back from the straight edge(s) on both sides.


Butt joints are, as the name states, when two similar thickness pieces are joined edge to edge with both pieces in the same plane (flat). Metal 1/8” thick or thinner are butted tight together, or at least without any gap larger than the filler wire diameter. If you have any wider gaps, true the edges, or cut another closer fitting piece. Trying to bridge a gap wider than the filler wire thickness is asking to blow holes in your seam. I will discuss in a later lesson what to do if you have no other choice but to bridge a larger gap.


To make your first butt joint weld, lay two of the practice pieces on your welding table long edge to long edge. Secure them in place with a welding magnet placed across the seam a couple inches from the right end (for right handers) or use a couple clamps to clamp them down. Be sure to attach your ground wire clamp to your steel topped welding table or to a bare metal portion of one of your holding clamps if using a cement board topped bench. The two pieces should be touching and flat across.
Use the same gas, heat and wire speed settings you used before.


The first thing we will do is tack the two pieces together. A tack is a minimal spot weld with 1/2 or less penetration designed to hold the two pieces together strongly enough that they can be handled and small alignment adjustments made, but not too solidly so that the tack can be broken apart and redone if the alignment is off significantly.
To perform a tack, adjust the wire stick out to about 1/2” with a freshly cut end. Hold the torch so the wire and contact tip is perfectly vertical to the metal surface and touching right on the joint. Scratch lightly with the wire, feeling for the crack to verify you have the wire right on it. Use your other hand as a bridge to support the torch and to hold the wire in place. NOTE: DO NO TIP THE TORCH, keep it vertical! When ready, hold steady and press the trigger for a count of “one- one thousand one, one- one thousand two” then release the trigger and lift the torch in one motion. Shut off the machine and carefully examine your tack. You should see a round pimple directly over the seam about 3/16” in diameter. It should be a flattened shape with a small depression in the center. The metal should be cool enough to pick up with bare hands and turn over. There should be a heat discoloration ring on the back, but no sign of melting or penetration. If you hold one piece and shake it, the tack should hold, but if you grab one piece in each hand, bend and twist them the tack should break. If you tacked the pieces successfully, grind off the remnants of the tack, place the two pieces back on the welding table and retack them together. Now we will tack the other end of the pieces together. If you don't tack in at least two places the heat of welding will warp and move the seam out of alignment as you weld. Be sure the two pieces are tight together with no overlap along the seam. Adjust as necessary with pliers, soft faced mallet or body hammer and dolly until you have the best alignment possible. Now clamp and repeat the tack at the other end of the seam. Once you have two good tacks holding the pieces together recheck the alignment along the seam. If there is flexibility along the seam due to the thickness of the metal or the distance between tacks, add another tack 1/2 way in between. We are now ready to weld or “run” the seam. With 6” of 16 ga metal we can run the seam from one end to the other in one continuous bead.

Clamp the metal down on the bench near to and parallel to the front edge. With the machine and our helmet off we will once again practice the welding movement.


When starting a bead from a tack or a previous bead, you do not start where the previous bead ends, or you will get a skip or pinhole. Rather we will start from where the end of the filler wire was when the previous bead was stopped. In the case of a tack, that is right in the center where the little depression is. In the case of a bead, if the bead is 1/4” wide, then it would be 1/8” back before the bead ends. If the first tack is too far inside the start of the seam, start your weld bead at the beginning of the seam and weld right over the tack as if it wasn't there. Same goes for the end of the seam.


So to practice, hold the wire so it is touching vertically where you want the bead to start, tip the torch 10-15 degrees pointed in the direction of travel. IT IS CRITICAL that you keep the wire running right down the center of the seam and DON'T TIP IT TOWARDS or AWAY from you. If you do, the majority of the heat will be concentrated to the side it is pointed at and you will either get a burn through, the bead will wander, and/or you will not get full penetration in the joint. Practice moving the wire right down the seam and holding your head where you can see the puddle and the seam ahead. REMEMBER: you must be able to see to weld!
After making about a 3” weld, stop and examine the weld. You should have that nice 1/4” low dome bead running centered over the seam on the top side and full penetration on the back side with no remaining edges visible. Adjust your settings, welding speed, bead control as necessary until you get a perfect weld. Common mistake is to raise the torch tip as you go. Concentrate on maintaining your tip height.
HINT: The more stick out you have, the cooler the arc becomes. Use a consistent height for consistent penetration. As you gain proficiency you can use this hint to reduce the heat as you approach an edge by lifting the torch, or use a longer stick out to reduce the heat when you are getting a little too much penetration on thin metal. Don't use stick out more than 1” long tho, the hot wire will bend and jump around making control near impossible.
If butt welding two different thickness of material, tip the torch slightly (2-5 degrees only) towards the thicker material to concentrate more of the heat on the thicker piece. Don't tip it so much that you miss the seam though.


Next most common weld seam is the fillet or “T” joint. This joint is where the edge of one piece of metal is welded somewhere onto the surface of a second piece of metal in a T shape. The bead is run along the inside corner on one or both sides to form a fillet which joins and strengthens the junction. To do this type joint you first tack both ends to hold the loose piece. Since the gas cup will not let you bring the contact tip as close as with the butt joint, you will need a little longer stick out. Trim the stick out so the end of the wire can contact both pieces of metal right in the corner. The gas cup can sit against one or both sides. Direct the wire straight into the corner near one end and do a 2 sec spot tack. Check that you are satisfied with the location and orientation of the pieces, adjust or break off and retack if necessary. If you are happy, do another spot tack at the other end to hold everything in place.
HINT: You can use 1 or 2 welding magnets to hold a piece at a 90 or 45 degree angle to another, or make a metal or wood jig to hold a specific angle. If it isn't critical you can hold the loose piece with your gloved hand while you tack it.
To complete the weld retrim your stickout so the gas cup touches into the corner. This will allow you to ride the gas cup along using the metal as a guide for the accurate placement of the fillet bead. The torch should be pointed 10-15 degrees towards the direction of travel (You will “push” the bead) and very slightly towards the piece of metal that sticks out both sides. The edge of the other piece will get hotter, and we want penetration to go through the flat piece, so direct the heat accordingly. Examine the bead shape and penetration like for the butt seam. For an extra strong joint weld a fillet on both sides. Don't try to compensate for lack of penetration by adding a second bead though.


A lap joint is done similarly to the T joint except you concentrate the heat onto the face of the upper piece near it's top corner, so the top corner melts into a shallow fillet. Turn over and weld the other side of the overlap.


An L joint can be done in one of two ways depending on which side's appearance is more important. If having a clean outside corner is more important, weld with a fillet weld on the inside of the corner like with the T joint, directing the heat equally between the two pieces.
If the inside of the corner's appearance is more important then the way to make a strong weld on the outside corner is to NOT place the face of one piece against the edge of the other like if you were joining two boards, but to carefully place the two pieces with just their inside corners touching so the two edges form an open V shape along the outside of the corner. When welding them together your bead fills that V.


The last common weld joint you might make is a plug weld. This joint is often used in place of a spot weld, or when welding a rod or tube into another tube. You drill a hole or series of holes in the outer panel or tube and weld it to the lower or inside piece by starting your bead on top the edge of the hole and spiralling into the center until your bead fills the hole. HINT: a stepped drill (looks like a modernistic steel Xmas tree with a ¼ cut out, Irwin makes good ones, available at your DIY store.) drills nice round holes in sheet metal without catching and tearing like twist drills. You can also use them for enlarging or rounding a small or misshapened hole for welding in a round filler plug. Just don't burn it up by trying to drill metal > 1/8” thick.


Practice welding various types of joints in metal 1/16 -1/8” thick.



Next lesson we will concentrate on welding thinner sheet metal. Be sure you have a spool of 0.023 wire (preferably easy grind), a copper backing plate or spoon, and a body hammer with a flat and pick end and a universal or heel dolly on hand along with a 4 or 4-1/2” angle grinder and 40 grit red fiber disks.

 

Ax, keep up the great work..

 

Excellent, waiting on the next installment.

 

Ax, I am just back from vacation, and anxious to resume welding practice. This latest lesson (above) will be first priority, and I'll get the tools for the upcoming lesson. Thanks again for the effort you are putting into this, makes me feel lazy if I don't go out and practice!

 

It's good to hear that I've inspired at least one of you to actually pick up their welder and practice what I've written! I hope it's going well.

 

Ax, thanks for all the effort put into the lessons. I will use the information as a referance. chuck

 

more to come shortly. Life has gotten in the way for a bit.

 

Your inspiring me also Chuck. Your lessons here have taught me a great deal and I want to tell you that I appreciate what you are doing. Thanks eh.

 

Anyone have any questions or comments on their welds? Maybe some pictures of your progress? Anyone set up a welding station/welding bench? Pictures?

 

Ax:
When welding together two pieces of material that are of different thickness:

Do you set your welder up for the thinner piece, and pull the puddle from thin to thick?
Or, do you set the heat to match the thicker piece, and pull the puddle from the thicker steel to the thinner piece? (trying not to burn through)

I did the latter, and I have a slight raised ring on the back of my thinner piece, which indicates to me i have decent penetration? (.23 wire, @ 15lbs gas pressure)

(I was welding 1.5" steel discs (1" thick, cut from round stock) to 12g plates that will hold my shoulder belts up in the cab corners. I'll post pics later tonight)

Also, what are your recommendations for gas pressure, in relation to different metal thicknesses? (For 18g sheetmetal, i've been running at about 8-10lbs.)

And once again, THANK YOU for the tutorial.