How to Tig Weld Using the Lay Wire Method

Pipe Welders and Boilermakers use a Tig welding technique called the "lay wire" technique.

What it means is that the tig welding filler wire is held in the weld puddle all the time instead of being dipped in and out as will traditional tig welding techniques used for sheet metal.

Pipe welding is different from sheet metal welding and pipe welders are a different breed than those who weld sheet metal.

For one thing, Pipe welders often use a technique known as "walking the cup". This is a technique that works especially well for pipe and not a whole lot else.

Aerospace welders, motorsports welders, sheet metal welders, and most other job shop tig welders do not find much use for walking the cup. But the lay wire technique can be useful for lots of jobs.

Any tig welding job where the thickness is more than 1/8" inch or. 125"... or about 3mm might be able to be done using this method. Especially if pulse parameters are used.

A note of caution: There is always a risk of lack of fusion when you use this technique on fillet welds because leaving the rod in the puddle can chill the puddle and can conceal the leading edge of the puddle making it difficult to ensure proper fusion all the way into the root.

I have heard of recent failures in socket welds where lack of fusion in the root was a contributing factor to the failure and socket welds are very often welded using the lay wire method.

But a socket weld on a power plant that goes through thermal mechanical fatigue is much different that a bracket for your headers on a hot rod project.

So the bottom line is this: use the lay wire method scrupulously. Like when aesthetics are the important thing. When absolute complete fusion is required all the way down in the root of a fillet weld, the dip method rules.

Tig Welding Cast Iron on Alternating Current

I have a secret for welding cast iron…. But you have to keep reading to find out.

Cast iron is hard to weld. Golf is hard too. But welding cast iron is kind of like playing golf. Every now and then you have a good day and you are lulled into thinking it's not so bad. That is because welding cast iron is like flipping a coin. One job goes pretty good…the next job makes you cuss.

Why is that? 2 main reasons… Reason #1 There are many different grades of cast iron, some more weldable than others. And it is difficult to tell them apart. By looking at the sparks it makes when grinding, and also by looking at a fractured surface some old timers can tell the difference in cast iron. But that guy is rare. In fact, when is that last time you talked to an old timer welder about welding?...... Oh snap! I just realized something……. I am an old timer myself now. Son of a gun! What an epiphany? With 33 years of welding under my belt, what else would you call me? I don’t feel that old some days…at least I still take the stairs 2 at a time. Reason #2The environment the cast iron has been in makes more difference than anything else. Exhaust manifolds are by far the hardest cast iron welding job to tackle because they are just flat impregnated with carbon from years of heating and cooling and being exposed to burning fuel exhaust.

Welding a broken cast iron leg off of grandmas old pot belly stove is easy. It has not been exposed to hot gases for 20 years. (Except for Uncle Percy's long boring stories. )It broke because Uncle Percy, tripped over his spit cup and knocked it over. Once you weld the cast iron leg back on, if Uncle Percy trips again, it will break again. If not, it will be good to go for years to come.

On the other hand, The exhaust manifold from Uncles Percy's boat motor. You know, The outboard that he bought used 30 years ago and he forgot to drain out the water last winter so it cracked.???... That one is not going to be so easy.

( disclaimer... since some guy broke my balls on the technical correctness and design of outboard motors... I did pull this out of my rectal database and have no expertise in fixing boat motors.... but we get the point anyway, no? )

Enough BS…So what is the best way to weld cast iron? The way you can make work. I have my own little secret for welding cast iron and I will tell you in a minute.

Lets look at some real simple metallurgy.

Mild steel has less than 0. 2 percent carbon. That’s 0. 2% or 2 tenths of 1 percent. That’s not much.

Medium carbon steel has more than 0. 2% and will harden if heated red hot and quenched.

Cast iron has anywhere from 3 to 8 full percent of carbon. That’s way more than 10 times what tool steel has.

And will get as hard as Japanese arithmetic when you weld it if you are not careful. Brittle too!

This is why often times when you weld cast iron, you hear it crack somewhere away from the weld. The weld metal shrinks and stresses the brittle cast iron around it enough to crack it.

So how do we combat this?

Here is what I do….

1. Clean the metal:

This means groove out the crack, and grind to shiny bright metal all around ½" past where any welding goes on.

2. Preheat if possible.. really hot, like 400-500f

3. If the part is small enough, an old gas grill bought on craigslist strictly just for preheating cast iron would work great.

that way your wifes London broil wont taste funny.

This gas grill was advertised in craigslist for FREE... just needs burners. It would make a great preheat and post heat oven.

There are 2 thoughts here…. either preheat the piss out of the whole part and keep it hot while welding and cool very slowly, or….. If the part is too big to preheat, still clean and groove out crack, but keep heat input to a minimum. But Most parts I see can be preheated. And when you can preheat, do it. Then whats the best way to weld it? Here is my little secret: Are you ready???

I tig weld on A/C with A/C balance control maxed out and use Aluminum Bronze filler metal
Its strong, it flows really well on A/C, dilution is low, and shrinkage stress is low so it does not tend to crack other areas next to the weld.

This method works great for tractor and farm equipment and machinery, But may not work as well when you have a lot of thermal cycles like on an engine.

For that type of application My choice would be to stick weld using a nickel rod also known as Ni Rod. (the Ni is pronounced like"eye" with an N)

Sometimes the flux on the stick electrode can help dissolve some of the excess carbon.

Another possibility that I have experimented with is to Mig weld cast iron. If you are going to try this, you need a ball peen hammer in one hand and the mig gun in the other.

As soon as you finish a short bead and while the bead is still red hot, peen the weld bead with the ball end of the hammer.

This helps combat the shrinkage of the weld metal. I have also experimented with some success, using a small mig welder and feeding extra nickel rod in like I was tig welding to keep the weld from hardening.. HAH… I bet you never thought of doing that.

I have also tig welded cast iron with high nickel tig rods with some success, and I have even beat the flux off a Ni rod and tig welded cast iron…

Bottom line is still the same, one cast iron welding job goes good, the next one makes you question the meaning of life.

The filler metal designation is ERCuAl-A2 in case you want to google it or ask your local welding supply for it...

most assuredly, they will have to order it, its not asked for that often.

Peace out…..

Miller Tig Welders Wireless foot pedal Amperage control

Who needs a Miller Tig wireless foot pedal amperage control?

I guess you could say that no one really needs it because we have all been getting by with our corded pedals forever.

But I can sure think of some jobs I have done where it would have come in super handy.

From what I have heard, The Miller tig welder wireless remote pedal is going to cost a pretty penny.

But there will be some welders who will be interested in this thing no matter what it costs.

Welding chromoly tubing on small aircraft…having to snake in and out of all those tubes is a real hassle with a corded pedal.

Race car builders…. for the same reason…when you are crawling and climbing in and out of a race car chassis, one less cord sounds like a great freaking idea.

And what about welders of marine hardware like tuna towers and handrails?... or large projects on a welding table or fixture where you are constantly swapping sides of the table and even getting up on the table to tack or weld.

Here is how the miller tig welder wireless foot pedal works.

The pedal has a small battery pack that is used to power the sending unit in the pedal. ( takes 3 AA batteries)

The pedal sends a signal to a receiver that plugs in to the canon plug receptacle …same place your corded pedal plugs.

Once the pedal and receiver talk to each other the first time, they are married.

…the signal is unique so other pedals or electronic devices cant interfere.

Have you ever worked in a shop with a bunch of other welders and had them do the ole foot pedal swaperoo with you?

I have.

.. I have been on both ends of this joke.

Its amazing how easily you can be fooled with a dummy foot pedal, by someone running your foot pedal and just mimicking your foot movements.

The kicker happens when you give it more gas for more amperage and nothing happens. So you give it more gas... Then all at once you get more than you can handle.

…so you let off the gas but it doesn’t respond…you are still hot as crap. You take your foot completely off the pedal …but you still have an arc and you are still hot as blazes..

You panic and break the arc. And it sounds like hell.

When you lift your helmet, 3 or 4 of your fellow welders are standing there laughing at you.

Ha, ha, very funny.

I am not advocating practical jokes. In fact, I think this one is a really bad idea.

Just telling a story how Boys will be boys…and sometimes grown men will be boys too.

Tip: get some Aluminum Angle for backing and a heat sink for welding sheet metal

Aluminum is a great conductor... its second to copper on the list of stuff to use as a heat sink for tig welding sheet metal. If you can get copper, thats like gold to a tig welder.

but scrap aluminum is a bit easier to find.

You might think about scrounging some random pieces of aluminum angle, aluminum plate, etc, for use to clamp to sheet metal for backing, to prevent warpage, and for a heat sink.

If you are building a tank, a drip pan, a catch basin for maple syrup, or whatever, aluminum works great as a heat sink you can clamp as backing on the back side of outside corner joint welds... its not as good as argon for shielding the back of the stainless steel weld, but it really helps and it a lot better than welding with nothing at all.

Stainless steel sugars on the back side when there is no shielding at all. Sugaring is another word for excessive oxidation... it leaves pits, traps bacteria and is generally not good.

Welding Stainless Steel Tubing Boatrails

Welding stainless steel tubing boat rails can be a gravy job but can also be extremely challenging.

Boat owners can be very picky.

Welds not only need to be strong, but they need to look nice too. In fact many boat owners have come to expect welds on boat rails to be pretty much invisible.

And why not? Welds do not have to be ugly in order to be strong.

316 stainless steel is often used for marine hardware like boat rails and Stanchion feet fittings because 316 stainless steel is more corrosion resistant to salt water than most other grades of stainless like 304 for instance. But retaining the corrosion resistance all the way through the welding process requires some attention to detail. For welding stainless steel tubing for marine applications, follow these guidelines:

• always use a stainless steel wire brush that has never been used for anything else
• use the right filler metal - if the stainless tubing to be welded is 316L, then use 316L filler metal
• Pay attention to the fitup - a tight fit, with no gap results in a better joint
• back purge with argon or use a split sleeve backing ring
• use the right amperage - just enough to achieve desired penetration, but non enough to turn the metal gray
• for welds that will be subjected to salt air, a polish followed by a pickling paste helps increase corrosion resistance

In addition to the tips above, use a tig welding technique that lets you minimize heat input - like pulsing the current if your tig welding machine has pulse capability.

P. S. Some welders have found that a pulse setting of about 40 pulses per second, a percent time on of 30 percent, and a 30 percent background current is helpful in minimizing heat input.

How to Weld Stainless Steel?

There are three common ways to learn how to weld stainless steel. SMAW (shielded metal arc) or stick welding, GMAW, commonly referred to as Mig welding (metal inert gas), and GTAW (tungsten inert gas) or Tig welding.

Stick or Arc welding.

The methods to weld stainless using an arc welder differ little to that of welding mild steel. Generally a small gauge stainless steel electrode is used for arc welding stainless metals. A safety note of caution, like mild steel there is a coating of slag left on a completed bead, with mild steel the slag needs chipping off, however stainless slag has a propensity to 'ping' off as it cools. This can cause serious eye damage so always wear eye protection using stainless electrodes. Using an arc machine is a relatively easy way to learn how to weld stainless steel

Mig welding stainless steel.

Again a similar process used on mild steel. Obviously you will need to exchange the mig welding wire for stainless steel wire. This is usually available in 304 and 316 grades. Use 316 grade stainless wires in high corrosion areas and for marine applications. You will also need to use pure argon gas instead of c02 that is used for mild steel. Mig welding is common in metal fabrication shops.

How to Tig Stainless.

This method is the most difficult to learn how to weld stainless steel, however in my opinion it is the most satisfying and offers a pure joint between base metal and filler metal.

Using a tig requires more skill but in a way is similar to using the Oxy-Acetylene gas process. Tig welders use a small hand held torch that carries a tungsten electrode to create the arc. Tungsten is used as it has an extremely high melting point. The tungsten tip, when struck to the metal creates the arc and begins the fusion process; at this point a filler rod is introduced to add substance to the joint. This is where the operator needs a steady hand.

Learning how to weld stainless steel comes down to using the correct equipment and choosing the best process for the job. For basic welding of stainless the arc or mig process will suffice, however if you require a top quality finish or are constructing an item that requires a clean finish such as a commercial food mixing component the tig welder is the way to go. As with everything using the correct process and practice will soon get you to expert status in no time.