I propose we make a sticky welding thread. I see questions about it constantly, and I've seen the same ground covered countless times!

For example, the comparison of MIG vs. TIG, attributes and drawbacks of each, where to buy, how to use...

I see a current thread suggesting you can't weld aluminum without AC, which is wrong.

I have seen lots and lots of great info regarding welders and welding... We should keep it in one place!

[from moderator]

Feel free to discuss anything related to welding in here, from which welder to buy to what techniques to use etc.

 

Good idea. I second this!

 

i don't agree. i think welding needs it's own forum.

 

i agree that welding needs it own forum but brent or someone said thats part of the jy section. so i'll take a sticky over nothing.

some things i would like to see on here would possibly be the welding and construction of an intercooler, thickness of aluminum for the fabbing of it, some examples of good welds and bad welds, possible cures for bad welds, suggested gas mixes for differant metals, suggested wire sizes for differant fabbing, even maybe some examples of welders in a certrain price range going from 110 to 220 versions, acceries that help welding. i know there are a lot of little tricks for people like me to learn from.

 

I took a 1000 hour weld coarse emcopassing stick mig and tig in all postions and pipe and am pretty confident in my ability to weld anything , but decided to pick up book called the welders handbook as it been recomned on here many other boards, for shits and giggle's , and i can say this book will answer the majority of weldling ?'s I've heard and had in the past , and it was only 12$ . Its far easier to use and under stand than my thickass textbook from school .

 

Dangerous Dan: This one?
http://www.amazon.com/gp/reader/1557882649/ref=sib_dp_pt/103-6776017-0138200#reader-link

I'm a beginner welder. Maybe I should get the book and start reading.

 

Yup , its a little cheeper at overstock.com .
Its a good read .

 

i have that book ...lol ...i got it from summit

 

if this is gonna be sticky worthy, you need more information, less conversation

 

Welding Overview

I guess I'll do a bit of a write up on my welding experience, which is almost exclusively TIG.

I use a Miller Synchrowave 250, which is capable of 305 amps sustained indefinitely. Water cooled torch, high frequency. AC/DC.

Let me first explain that. For turbo mustang fabrication, a welder with about 100 amps is mandatory. Most welders you can buy will support this. I never turn up the dial on mine to 305 amps unless I'm trying to get massive penetration into 1/2" plate.

The water cooled torch is a NICE option to have, but not mandatory. The TIG has lots of current running through it and that gets it hot. Most TIG's are air cooled, which makes for a rather large torch. Commercial style TIGs have water cooled torches, which allows you to run all day long without the torch getting too hot to hold. Nearly no one on this board will probably want to spring for the luxury of having a water cooled torch... When you buy a TIG however, ask if it can be later upgraded to water cooled, because it is very nice.

High frequency refers to the waveform of sinusoidal current in the torch. Essentially, this only matters for AC welding on aluminum and exotics. Without high frequency, you can't start an arc without physically touching the workpiece. With high frequency, you need only hold the tungsten electrode close to the workpiece, step on the go pedal and voila, you have an arc. I think most TIG welders these days have high frequency capability. Its something to make sure of, however.

Most of the cheaper TIG's are only capable of DC (direct current), and some can only do electrode negative DC. This is fine for only welding stainless and ferrous alloys. If you plan to weld aluminum, its *generally* easier to use AC. TIG's capable of AC (alternating current) are always more expensive. However, don't despair. You can weld aluminum with DCEN (direct current electrode negative) if you have helium shield gas. Welding aluminum with DCEN with helium in the mix is more difficult than AC, but entirely doable. The main downside is your aluminum must be clean Clean CLEAN!

I'm not going to get into MIGs because they are not my specialty. I will remark however to note the difference between a wire feed welder and a MIG. MIG stands for Metal Inert Gas. MIGs *are* wire feed, but they are also connected to a bottle of shield gas, which keeps the workpiece shielded from oxygen while its hot. Standard wire feed welders have special wire with flux in the center, which builds up a nasty crap layer of ugliness over the hot metal as its welded to protect it. Wire feeds without shield gas are a LAST RESORT!!!

 

Welding Mild Steel and Stainless

To TIG weld ferrous alloys, which include pretty much any kind of steel and stainless such as A36, 17-4, 304 and 321, you'll need red tungstens (which are 2% thoriated), and set the welder to DCEN.

One of the PRIMARY keys to good welding is cleanliness, cleanliness and cleanliness. Make sure your area to be welded is free of rust, scale, paint and oil. Use a grinder to get down to bare shiny metal. Clean it with some acetone or alcohol before welding. You'll find its not mandatory to do this, but it only helps.

The second key to good welding is good fit-up. When the two pieces you're welding fit like a jig-saw puzzle, its hard to weld badly. If there are gaps and crevices to fill.... Thats where it takes real skill and experience to do well.

What have we learned? Clean FIRST!!! Grind, file and tweak your parts so you get great fit up!

You'll find that stainless can actually be "sweated" together (if fit up is good), which is to say you don't even need filler metal. Just strike your arc, hold until a weld puddle spans across the seam, and move the torch across the seam. While this is really easy, there is no strength... You must add filler metal to get penetration, and get good metallurgy and strength.

Mild steel however generally won't do this... You'll have to use filler rod to join the parts.

The key to getting started is to strike a small arc on one part, and get a weld puddle to form on ONE part, right on the edge of the seam where it mates to the other part. Once this is done, move the torch slightly towards the other part, trying to develop a weld puddle on it, too... The idea here is to find the perfect position of the torch, so that a small weld puddle is present on BOTH parts at the same time. You'll notice the metal tends to want to pull away from the other puddle, because of liquid surface tension. NOW is when you dab your filler rod right between them to join them up. CONGRATULATIONS! You've just made your first bead. Move the torch slightly further along the seam and do it again, and again... Thats all there is to it!

Now, beginners tend to do this thing I call "gluing", instead of welding. Its important to realize the difference.

You are NOT trying to melt filler rod and drip it into the weld seam. You are trying to FUSE the metal together into one piece. Don't be afraid to actually MELT your workpiece. Thats the name of the game.

Beginners also tend to accidentally dip their tungsten electrode into the weld puddle, which at best will cause a glob of workpiece metal to solidify onto the electrode. At worst you'll find you just welded your torch to the workpiece.... Sometimes you'll even give yourself a bit of an electrical rap in the process. It happens to everyone. Don't despair. If you do this, wiggle the torch and break it free of the workpiece, re-grind a nice pencil point back into your tungsten and try again. Your weld however, doesn't stand a snowballs chance in hell of passing a X-ray exam once you've done this though. For the most part however, you can get away with this for 99.99% of the fabrication welding you do.

If you've dipped your electrode, and it has a glob of workpiece metal on it, you must re-grind your tungsten. If you don't you'll get arc scattering as well as contaminated welds. Once you become experienced, you can sometimes get away with a contaminated electrode... But its a pain it the butt... Just regrind it, its the correct way...

Sometimes you'll notice the arc doesn't start well once you've stepped on the go pedal. This never happens on a FRESHLY ground tungsten. Not sure why this happens... If it does, just lightly scratch the tungsten on your weld table, and the arc will fire right up next time.

A bit of practice and you'll be there in no time.

 

Welding Aluminum

Welding aluminum is cake. I swear, have no idea why its played up to be such a big deal. Its actually easier than stainless and mild steel.

The MAIN ISSUE is cleanliness. Make no mistake, if aluminum is going to weld well, it MUST BE CLEAN! There are some other issues about aluminum like castings and really heavy pieces of it, but for most fabbing, its a cake walk, and a lot of fun.

Set the welder to AC. If you have some kind of control to set the bias of the AC waveform, play with it and see what you like best. I like about 70% or so.

Some people say you need to "ball up your tungsten" and use a green tungsten.... Hogwash!

Using your standard red tungsten, sharpened nicely to a point, aim it where you want to weld, step on the pedal (you'll have to step on it a bunch harder with aluminum as compared to steel) and go.

The hardest part of aluminum is getting your first bead made. Aluminum conducts heat so fast that you really have to keep the torch still, in one spot and get some heat into it. Don't be afraid of the violent sound the arc makes.

Concentrate on your first bead. Aluminum gets very shiny as it starts to melt. Once you see the shiny spot, dab your filler into it (use 4045 rod for most aluminum alloys), and do so until the puddle sucks it in. Move the torch to the other side of the weld seam and get it to join up to the bead you just made. You may have to go from one side to the other a few times, because aluminum doesn't flow quite as fluidly as steel. Once they join up, the hard part is over and you can go like hell.

Sometimes you'll notice the weld puddle "rejects" your filler rod. As hard as you try to dip it in there, your rod turns into a nasty grey/black balled up gook of metal. YOUR WORKPIECE ISN'T CLEAN ENOUGH AND YOU PROBABLY HAVE A CONTAMINATED TUNGSTEN! Regrind the tungsten, grind the workpiece well, so its all bare virgin aluminum and try again.

Next installment I'll talk about aluminum on DC!

 

Great info Turbo. I have been hanging out on a couple of welding boards. There is a person on there who works for sylvania(sp) that makes the tungstens. He said Zirtung tungstens are the best for welding alum. on a sychrowave machine. I have some but have not tried them yet. I am using red ones sharpened as well and they are fine for me and nice and stable arc. I currently have a miller 180sd that I am selling to get a Synch. 250 machine.

T.J.
Ex. of alum project:
#ad

 

What Amps at say 3 mm ?

Good info..What amps for 3mm alloy??? To start with ???
I'm self learning Tig now...Thanks guys...

 

Generally I'll leave my machine dialed in for about 150 amps or so... Then just control my arc amperage with the foot pedal.

That is the beauty to TIG... Even with the machine set balls-to-the-wall at 305 amps, you can still weld .049" wall tubing.

 

the welder's handbook is the textbook used in the welding classes I took. I probably learned more from it than the actual classes.

 

About choosing filler rod

Alrighty... I thought I'd talk a little about choosing filler rod.

The idea is that certain metals have certain characteristics, which you will destroy or at least not be making use of if you weld with the wrong rod. Yes, you can use a coat hanger if in a pinch, and it will work, but now your joint is only as strong as coat hanger material, which is crap. Sometimes, a certain rod won't work at all.

Heres an example: Lets say you are welding high carbon steel (high strength), and you use low carbon rod... Carbon will diffuse along the gradient into the weld area, and away from your base metal. The result is a weld prone to cracking, and nowhere NEAR the strength it should have been for the application.

Usually you want to weld with a rod that is one grade higher alloy than the base metal you are welding.

Step one is knowing what kind of metal you are welding.

I suspect most fab work will be of mild steel (A-36), and the most common rod to use is called ER70-S2. This is a medium/low carbon content rod and works great.

If you are welding higher carbon steel (such as subframe connectors to your chassis), you should use a high carbon rod. ER70-S6 is a good choice here. This will also work well for your 4130, 4140 and 4340's... Think roll cages!

For stainless, the most common alloys are 17-4 (ferritic) and 304/321 (austenitic).

There is special rod for 17-4, called 17-4... Thats easy!

For 304, you'll want to use a rod called 308L.

What if you want to weld a piece of mild steel to a stainless?? Use 309!

As for aluminum, usually the rod of choice for nearly all aluminum is 4043. Beware that several aluminum alloys (the ones that contain a lot of copper) are not weldable!

My objective here is not to give you specific rod recommendations for every application, but to give you an idea about what you need to do and a little theory behind it. When you go to the welding store to buy rod, tell them what you are doing, specifically, and they can give you some good recommendations (usually... I've been given some seriously bunk recommendations before too!).

 

Re: About choosing filler rod

I always use 4043 .

 

Good point! I edited my post so that I wouldn't be posting inaccurately.

 

CHOOSING A MACHINE!!

Maybe this post should have been first! Purchasing a welder is a big decision. You'll probably have to budget for a while, and you'll probably be very excited about it.

The primary question I see on this site is in regards to buying either a MIG or a TIG. If you are reading this, you undoubtedly know that TIG is more versatile, but significantly more expensive.

At this juncture, let me tell you, TIG IS WORTH IT!

If you look through some of the examples of peoples' welds on this site, or any other, you will see that the accuracy and precision and overall quality of a MIG weld will never match that of a TIG weld.

While you can do an adequate job with a MIG, you'll find that the big, clunky and unwieldly torch is difficult to get into tight spaces (often encountered with header fabrication). Another disadvantage of MIG is not having the luxury to stop in a certain spot and fix a little blemish or weld bead you didn't get just right. TIG allows you to set your own pace. You can make 1 bead every 5 seconds, or 5 beads per second!

While I've never been given an engineering drawing that states "weld must be pretty", all welder's take pride in doing a pretty weld job. A MIG will never match the TIG in case either.

OK, I've been bashing MIG's for a while now. What are they good for? Long continuous welds on plates. TIG is a very time consuming process, and MIG can really haul some arse. For mustang fabrication, the only place where a MIG would be advatageous is welding in subframe connectors.

Another point of contention: Once you've become a reasonably good welder, you'll think of all sorts of new projects and ideas... So be sure you buy a welder with some room to grow! I would suggest most people buy a welder capable of at least 175 amps... Unless you intend on ONLY doing your tubo mustang project, and never weld again, you'll outgrow a ~100amp welder in no time. Honestly, you'll find when welding aluminum on AC, 175 amps doesn't cut the mustard. However, if you plumb in some helium with your shield gas, 175 amps goes a lot further.

Lastly: I can gauran-damn-tee you'll be much more impressed with the results of your turbo project if you buy and become proficient with a TIG. If its simply not in the cards though, a MIG will do the job.... Forget the stick welder!