This is a great thread AX, thanks again! And the safety info is great as well. I have been lucky so far, but always aware of the danger, which helps one stay lucky. That and having a good safe space to work in and the correct clothing. Way back in a sculpture class, where I first began working with metal (cutting, grinding, welding) I had two wake up calls. The first was loose clothing. My shirt got caught up in a 7" grinder that had a cup wire brush on it, after I had let go of the on switch. My shirt wound up so tight, so quick that I thought I might suffocate. Lucky for me one of my classmates was quick and he cut my shirt off from the back. How I managed to hold the brush off of my skin I will never know. NEVER wear loose clothing when working with anything that spins or cuts or burns. The second was really stupid on my part, but at 19 we think we are invincible. I decided that I would weld a patch inside the trunk of my '66 Volvo where the rear strut top mount had broken through. I removed the gas tank and line and covered the floor of the trunk with metal plate scraps. Not even 2 minutes after I crawled into the trunk and began welding the repair plate, with a stick welder, the sparks got into the jute below the plates I put down. It started burning instantaneously. I managed to get out of the trunk while trying not to breathe. Another classmate put the fire out quickly with and extinguisher and saved the car. I was OK, but scared to say the least.

 

Hi,
All things considered if you paid $72.00 U.S. I don't fell bad about paying $85.00 Can. I guess one could have done better on line but I have never bought anything on line and don't like surprises. The last parts I bought out of the U.S. the prices and everything was ok but then two weeks later got a bill for broker fees of $85.00. I never had to pay broker fees on vintage parts in the past years when shipped U.P.S. If I buy locally I can at least deal face to face if I'm not happy.

 

Hi oldmerc,
I deal with a small company called Gilbert Parts Depot who only have four outlets here in the valley. They have been able to get me most parts for my old Mercs at about half the price that other places charge. They are also an ESAB dealer. Due to their good service and prices on most parts I always try them first. They have gotten me some pretty oddball stuff over the years. They apparently talked to other local dealers and the warehouse in Edmonton but could only find the one 11 lb. roll on Vancouver Island. It will be interesting to find out if other people can find this product in this neck of the woods.

 

Bump.........................

 

Ax what happen??? I was waiting for the next installment. chuck

 

nothing really, I am in Buffalo visiting family for my neice's graduation from med school and her wedding. I wrote 1/2 the next lesson last night and hope to finish it today.
Life sometimes gets in the way.

 

AXRacer, THANKS for the stuff so far, and whatever comes next. I got my MIG welder, wire, gas, helmet, gloves, and am scrounging material to make my welder cart. Now I'm ready for your next lessons, whenever you have the time. This opportunity got me off my rearend to finally learn this necessary skill. Thanks again!

 

Lesson 6:
Before we set up our welders, let's talk a bit about the different types of steel we might want to weld or use on our trucks.

Steel can be categorized by the amount of carbon it contains with the iron, as well as the manufacturing process, and/or whatever other metals it is alloyed with. Each category has different working properties which makes it more or less suited for a particular purpose, and requires different handling.

First category is the special alloys. Various amounts of nickel added to the steel creates a corrosion resistant alloy commonly called stainless steel. Adding other metals can create high strength steels like chrome moly. Since we are concentrating on body work welding, we will gloss over these special alloys for now.

Carbon steels can be divided into high carbon, also called tool steels and low carbon or mild steels. High carbon is used for parts like springs, high wear parts, gears and shafts.
Low carbon or mild steel is the type steel that is used for body parts, and the type steel we will be using most of the time. Mild steel is very soft and “plastic” which makes it suitable for forming and shaping.

Mild steel sheet and structural forms (angle, channel, tube, beams, etc) are manufactured by two general methods: hot rolling or cold rolling.
In hot rolling a large cast ingot is run through sets of rollers while very hot (above the recrystalization temperature) where it is squeezed down thinner or into specific shapes, kind of like a pasta machine makes noodles from a ball of dough. Because the metal is so hot it can be squeezed a great deal in each pass, but the rollers need to be cooled and lubricated with oil sprays to keep from melting and sticking. The oil burns onto the steel forming a hard oxide that gives hot rolled steel it's characteristic grey/black hard surface coating. That coating should be removed by grinding or acid dipping for the strongest welds.
Cold rolling is a similar process to hot rolling except the ingot may start off cold and reheated or heat soaked to a lower temperature (below the recrystalization temperature) before rolling. Since the metal is cooler it does not form the oxide coating and therefore can be rolled to a smoother surface, thinner, and to close tolerance. Cold rolled steel sheet can be supplied in hard, half-hard or soft condition or temper. Hard or ½ hard would be best for flat or near flat panels or inner structures such as floors, firewall, etc. whereas shaped or formed panels would be best to be made from soft cold rolled sheet, sometimes called “weld steel”. There is an extra soft sheet called “deep drawing” steel that would be worth searching out or special ordering if you are going to be forming a lot of compound curved or custom panels.

For our first welds and practice it would be best to have a dozen or so rectangles of 16 ga cold or hot rolled sheet steel about 2”x5”,. If using hot rolled sheet, remove all the black oxide coating by sanding with a 40 grit fiber disk or soaking in vinegar for at least 24 hrs. and then scrubbed with a green nylon scrubbing pad.

There is one more type of steel you may commonly encounter in welding that needs special mention, that being galvanized steel. Galvanized steel is not a category, but rather a processed steel. It is mild steel that has been made corrosion resistant by giving it a coating of pure zinc, a dull grey colored (sometimes with a crystalline appearance) metal that is more chemically reactive than steel, so the zinc acts as a sacrificial coating that reacts with any environmental chemicals before it can react with the steel. Once all the zinc has reacted or the coating broken, the steel is then vulnerable to corrosion, unlike stainless steel which maintains it's corrosion resistance throughout.
The reason we need to take special concern with galvanized steel is the zinc has a much lower melting and vaporization temperature than the melting temperature of steel, and zinc fumes are a severe health hazard if inhaled. Galvanized steel can be MIG welded, but you need to take special precautions to protect yourself from inhaling the zinc fumes. Even a small amount of inhaled zinc fumes can give you severe headaches and produce a condition called “zinc shakes”, very unpleasant flu like symptoms that can last for days. If you must weld galvanized steel, grind off the zinc coating completely for at least an inch or two back from the weld on both sides of the metal. If you start welding on an unknown piece of metal and notice dense smoke and whitish or greenish powder forming along the heat zone, it is likely you have encountered galvanized metal. If you must weld on galvanized steel, weld outside while standing upwind, and/or wear a breathing mask rated for gasses, not just a dust mask.

Setting up the MIG machine for the first time use.

1. Unscrew the protective cap off the shielding gas bottle, inspect the regulator seat area for dents, scrapes, heavy pitting, dirt, or damaged threads. Screw on the regulator/flowmeter (we'll call it the regulator from here on to keep with convention). Do not use any sealant tape or dope, tighten firmly with a well fitting wrench, don't over tighten. If not already connected, connect the gas hose between the regulator and the machine. Open the valve on the tank completely until it stops. Check for gas leaks by painting all the connections with a solution of dish detergent and water and look for bubbles forming. We will set the regulator in a later step, shut the gas back off for now.
2. Lift the cover over the wire compartment and check which wire, + or -, is connected to which terminal. Refer to your instruction manual for the correct polarity for solid core wire, and switch or connect if necessary.
3. Plug in the combination cable to the torch and gas control plug into the machine if not already hooked up. Lay the cable out as straight as possible. Remove the gas concentrator cup by pulling it off the end of the torch, exposing the copper contact tip. Unscrew the contact tip and check what size is stamped on the side. If it isn't the same as the wire you'll be using (hopefully 0.023, or no more than 0.030) obtain one that is and set it close by at the ready. Plug the machine into it's power outlet but do not turn on the machine.
4. Check your wire feed rollers and adjust if/as necessary for the size wire you'll be using. We will set the drive pressure in a moment, but be sure it is “on”, not released. CAREFULLY open the spool of filler wire, being sure to NOT release the wire or it will jump loose and snarl!!!! Place the spool in the machine, and secure the spool. If the spool is secured with a large tension nut, be sure which way to turn it, it may be left hand threaded. Clip off any bent portion of the wire with your cutting pliers. Carefully start the end of the wire into the feed system being careful that the wire stays coiled tightly and evenly on the spool. Holding the wire in place, set the power **** at it's lowest setting (above “purge”) and turn the wire speed **** up to about 10 (on a 0-100 scale). Turn the machine “on” and press the trigger button on the torch. The wire should catch and start feeding, continue feeding until the wire appears at the end of the torch. When about 6” of wire is showing release the trigger and shut off the machine. Slip the contact tip over the wire and screw into the torch tightening it finger tight.
To adjust the wire feed tension, hold the torch so the wire is pointed at a 45* angle and 12-18” away from a block of wood. Turn on the machine and press the trigger. Adjust the tension to the minimum that will feed against the wood without slipping.
5. Adjust the gas flow. Turn the valve on the gas tank on full, until it stops.
If you have a regulator, it will have two gauges. The one closest to the tank is the tank pressure, like a gas gauge telling you how full the tank is, There are two scales, a red scale and a black scale, one reads in lbs/sq in, the english system of measuring pressure, the other scale is in bar, the metric system. A full tank will read about 2000 on the english scale.
The other gauge closest to the hose going to the machine is the flow rate. It too has two scales: one red one black. One scale reads in cu ft per hr, the english system, the other reads in liters per min, the metric system. HERE'S THE KICKER!: the colors of the two systems are opposite the colors used on the other gauge!!! Don't ask me why, just accept it and be sure which system you are reading on each gauge. We will use the english system. The flow rate is adjusted with a **** or screw on the regulator. Turning it in or clockwise increases the flow, turning it out or counter clockwise reduces the flow rate. We cannot accurately set the flow rate unless gas is actually flowing, so we need to put the gas concentrator cup on the torch, turn the machine on, set the power to minimum or “purge” if it has that setting, and turn the wire feed speed down to it's minimum setting. Now while holding the trigger button down on the torch, adjust the regulator to a setting of 20 cu ft/hr (the usually recommended flow in the directions) if welding outdoors or in a building with fans blowing, or set to 10 cu ft/hr if welding in a shop with still air. The lower setting will use ½ as much gas, so is much more economical, but will work fine if the gas isn't being blown away. Never try to weld in even a moderate breeze no matter the flow rate, outside without a wind block or with a fan blowing directly at the welding area.
6. Finally we need to set the power setting and wire feed rate for the material we are welding. Every machine I have ever seen has a spreadsheet type chart under the “hood”, the cover over the wire spool. You start reading the first vertical column on the left, and eliminate any horizontal rows that don't apply until you reach the column for the metal thickness to read the power and feed rate. If the actual thickness of the metal doesn't appear on the chart, just pick the settings for metal one thickness thicker or thinner to start with. The power and speed settings are just to be considered suggested starting points, you must test them and adjust for your particular method of welding, every welder (person, not machine) welds slightly differently, and even two different machines will work differently.

OK! We are ready to make our first test weld... Next lesson.

 

bump. Good information.Why don't the moderators make this stationary during the life of this thread? chuck

 

Lesson 7: Seeing is welding!

There are two kinds of welders, a welder and a hack. The difference between them is the welder sees what and where he is welding so he is in control of his welds, the hack welds by feel and by guess so his welds are all over the place in terms of quality, consistency, and placement. By following my instructions, I will teach you to be a welder, not a hack.

Let's get ready to weld!
To SEE what you are welding, it is critically important to get into the correct position to weld!
Hopefully by now you have set up you welding station: an area with a welding bench (a steel plate topped table or bench 36-48” high), an adjustable height chair or stool, the welding machine placed so the controls are within arm's reach, your MIG pliers, gloves, helmet, welding magnet and/or clamps all within arms reach, and a couple pieces of 16 ga. Mild steel plate. If you still don't have a welding bench, before you go any further, run down to your closest big box DIY store and buy an inexpensive piece of 1/2” fiber cement ceramic tile backer board and three 2x4”s. Make a simple set of 36” legs from the 2x4 for the fireproof cement board top to form a bench (make the legs so the top overhangs the base a couple inches all around). Go to your neighborhood thrift store and buy a used gas lift office chair.

To get yourself in the correct seating/viewing position, sit comfortably in the chair and adjust the height until the table top is at armpit height. Place your practice piece of steel on the top of the table near the front edge and clamp in place with a magnet if working on a steel topped bench, or with a clamp if working on the FCB top so it won't move around. Now temporarily prop up a newspaper or pocket book in the center of the practice piece. Move your chair and head around until you can easily read the bottom line on the page. Your eyes should be about 12” away from the writing, the average reading distance. Note exactly where and how far away your head is. THIS IS WHERE YOUR HEAD AND EYES SHOULD BE WHEN YOU ARE WELDING, NO FURTHER AWAY! If you need reading glasses to read this far away, wear them under your helmet or buy diopter (magnifying lenses) that clip inside the face plate of your helmet.
Now it's time to learn to position the stinger and how to move it and what to watch. If there isn't an inch or two of filler wire sticking out the end of the contact tip, turn the machine on and press the trigger to advance the wire. Turn off the machine, we will practice first “cold”, with the machine off, without your gloves or helmet on. Use your wire cutters to adjust the STICK OUT, the amount of wire protruding from the contact tip when starting a weld, The stick out should be ~3/8”.
Hold the stinger with an easy grip in your dominant hand with your index finger on the trigger. Lift your elbow high as comfortable into what I call the broken wing position until the filler wire is perfectly straight up and down and barely touching the practice plate near the center just inside the right edge(assuming you are right handed, reverse all directions if you are left handed like me). Now tip the torch to the right 10-15 degrees so it is pointed in the travel direction of right to left. Be sure to NOT tip the torch towards or away from yourself! Form a support bridge with your left hand by placing it under the torch just behind the gas cup with you wrist or forearm resting on the table. You should be looking directly at the tip of the filler wire where it touches the plate. If you can't see the wire clearly, adjust your head position until you can. Practice moving the torch slowly across the plate in a straight line from right to left, you will almost always weld by pushing the bead in front of the torch in the weld direction rather than dragging it. The end of the filler wire should be barely touching the plate but not supporting the torch through the entire practice pass. Do this several times until you can move the torch in a straight line while supporting the contact tip at a constant height while moving it slowly at a rate of 1 second/inch without changing the tip angle. Practice while holding down the trigger button(with the machine off for this part of the exercise). Carefully and with concentration watch the end of the wire as it moves across the plate! Once you can perform this exercise with precision, put on your gloves and helmet and repeat for several more cold passes. Be sure you are pressing the trigger fully, not using a death grip. I like to use the edge of the table and my support hand to guide the torch in a straight line. Make sure you can slide your hands along smoothly without dragging or stuttering or changing the torch height or angle. When you are comfortable and confident with your the cold practices. It's time!

LIGHT EM UP!

Now, remember there is no rush! There is nothing bad that's going to happen the instant you press the trigger, and nothing at all is going to happen until you do, so don't change anything from your cold practices. Adjust your wire stick out length and clip off any balling on the end of the wire left over from a previous weld with your cutters before starting a weld. ALWAYS start with a cleanly cut wire end with 3/8" of stickout

Turn the machine on, set up the torch position and angle by holding it perfectly vertically, then tip it the 10-15 degrees in the travel direction. The end of the wire stickout should be touching the plate exactly where you want the bead to start. Be sure you can clearly see the end of the wire, under the gas cupyour head and eyes should be no more than 12” away, and just above the table surface!

OK, here we go! Press the trigger. Expect the torch tip will drop when the filler wire starts to melt so be prepared to support it with the left hand. Hold the torch still for a moment until a puddle starts to form around the end of the wire. The vaporizing arc will be very bright, and the puddle will be a much darker red around the bright arc. Wait until the puddle is about 1/4” in diameter, then begin moving the torch at a slow speed, maintaining the torch angle and height for the entire weld. Concentrate on watching just ahead of the leading edge of the puddle, NOT THE BRIGHT ARC! You want to move slowly enough to keep the puddle ~ 1/4” in diameter. A speed of an inch/sec is about right, most move the torch too quickly the first time, it's not a race! If you are having trouble seeing the puddle, try glancing behind the arc for a moment, it is easier to see and recognize back there, but don't get in the habit of watching the trailing puddle alone, you want to see where you are going, not where you've been! That's like trying to drive down a road by only looking in the mirrors to see if you stayed on the road. Try moving your head a little to the right (towards your torch hand) and look down the wire more so the contact tip shields part of the arc, kinda like using it as a sun visor, but be sure you can see the very end and the puddle.

Stop before reaching the end of the sheet. Shut the machine off and let's closely examine the weld we made.

First look at the width, height, and shape of the bead: Ideally it should be about 1/4” wide, even in width along the entire length. It should be lower than wide with the edges blending smoothly into the sheet with a slight fillet.
Use your pliers to flip the sheet over and examine the back. The darkened edges that define the heat affected zone should be even and a little wider than the bead on the other side. The area directly under the bead should have a slightly rippled surface even with the back to very slightly raised, no more than 1/16” inch, showing that the molten metal penetrated completely through the sheet.

Some less than desirable results and their typical causes and corrections:
Narrow tall bead. Moved too fast, slow down.
Uneven bead width. Moved at uneven speed, Make sure your hands are not catching on the welding table, move slowly and deliberately, watch your puddle size.
Wide flattened bead. Moved too slowly, speed up, watch puddle size. If the edges of the bead is below the rest of the surface the heat may be too high, reduce the power and wire speed to that for one metal thickness thinner.
Bead is undercut where it meets the sheet, high compared to width. Bead is sitting on top the sheet, heat is too low, increase power and wire feed speed to settings recommended for one thickness heavier, move slower.
Back of sheet flaws and corrections:
Narrow heat affected zone, no evidence of melting. Insufficient penetration, moved too fast or heat too low, adjust as needed.
Wide heat affected zone, excessive penetration producing heavy bead or drips of previously melted metal on the back, burn through holes. Heat is too great, increase weld speed or reduce heat as needed.

Wire speed adjustment: If the feed rate is too slow the sound the weld makes will be more like popping popcorn. Correct speed will sound like steadily frying bacon. Too fast a feed rate will push the torch away from the plate. Don't confuse too fast feed rate with lifting the torch as you weld. Moving the tip closer to the plate will increase the heat, moving it further away will decrease the heat.

Your assignment until next lesson is to practice, analyze, practice, analyze, practice, analyze, etc etc etc. until you can run satisfactory beads consistently. A few hours of practice should make a great improvement if you try to improve each bead over the last and make sure you are really seeing your puddle and what you are doing, not just glazing over and repeating mistakes.


Note, I re-edited this lesson from it's original content. The changes are in orange just to make it easy to see what has changed, not to add extra emphasis. If you are reading this lesson for the first time pretend the orange text is black like the rest of the post.
Chuck

 

double post sorry!

 

Ax,

I've been following your post and wanted to let you know that your reach as a teacher is going beyond FTE. I'm not a brand loyalist and am proudly considered a darksider by most standards in this forum in regards to my '53 F100. At any rate, I posted a link to your work here on stovebolt and you have some appreciative fans from that site as well. Thanks for taking your time and investing it into this great hobby. Panel welds - The Stovebolt Forums

 

I'm glad others are finding my lessons useful as well. New lesson coming soon:
putting humpty dumpty together again, welding a seam.

Has anyone gone out to the shop and run a few beads? How did it go?

 

AXracer

Thanks for the welding classes
I am looking at the Eastwood MIG 175 and what is the spool gun used for (never seen one )

Thanks again

 

A spool gun is a very handy and necessary accessory if you ever want to weld aluminum. You can buy one for some of the other welder brands and models (check the instruction manual or specs to see if a welder you have can use one), but they sell in the 300.00 range!
Since aluminum filler wire is pure aluminum, it is very soft. In theory you could simply replace the wire spool under the hood of the machine with aluminum wire, but pushing the wire thru 10' of combination cable is like trying to push a rope uphill. it wants to jam and birds-nest constantly, making for a frustrating experience. The spool gun holds a small spool of wire and feed rollers within a few inches of the contact tip and always in a straight line, so jams are much less likely. If all you want to do is a few short tacks and don't mind having to clear jams and throw wire away, then try using your machine without a spool gun, keeping the combo cable as straight as possible. You will also need to switch shielding gas for aluminum, usually to pure argon.
Even if you don't have immediate plans to weld aluminum, having a spool gun in your tool box is worthwhile. The Eastwood 175 is a bargain since the gun is included, and would be my choice for a new machine if you have 220V power in your shop.