Notes on engineering (again)
One of the toughest things to do in any engineering is to join materials. The choices have changed over the years, but the basics haven’t; you can use fasteners, you can use adhesives, and you can weld.
Most people think of welding as something you do on metals, but plastics are welded, certain kinds of rubbers are welded, and some types of glass can be welded.
Sometimes dissimilar materials can be welded together, sometimes they can only be adhered- case in point, it is possible to silver solder gold to steel (done in fancy firearms inlays all the time) but gold and steel cannot be welded. The solder acts as an adhesive, making a bond with both metals. The greater the delta coefficient of thermal expansion of the materials, the greater the possibility that the joint would fail (this is incidentally why automobile engines with aluminum heads are notorious for losing head gaskets- Aluminum has a coefficient of thermal expansion of 13.7X10^-6 inches per inch per degree farenheit, while the coefficient of thermal expansion for cast iron is around 10.4X10^-6 inches per inch per degree farenheit.(from the materials selectior, Reinhold) THe two items expand and contract at different rates, and eventually, scrub the damned gasket right off.)
Anyway- back to joining materials. Most anything that needs to be serviced is joined using fasteners, and the range of fasteners is more huge than it’s ever been. Welding, though, is still a very important solution for a huge variety of reasons.
THe problem is, the very best welds are made while the two pieces to be welded are laying flat. When you’re learning to weld, this is how you learn, with flat pieces. And it’s usually the last time you ever have that luxury.
Welding is such a critical process that the ASME has established standards for the quality of welds, and those standards are damned tough to meet, some requiring years and years of practice. Here’s an example:
Welding Positions For Groove welds:-
Flat
Horizontal
Vertical Upwards Progression
Vertical Downwards Progression
Overhead
Pipe Fixed Horizontal
Pipe Fixed @ 45 degrees Upwards
Pipe Fixed @ 45 degrees Downwards
Welding Positions For Fillet welds:
Flat (Weld flat joint at 45 degrees)
Horizontal
Horizontal Rotated
Vertical Upwards Progression
Vertical Downwards Progression
Overhead
Pipe Fixed Horizontal
These weld positions are the ones most commonly encountered by field welders, and it is their job to know how to do them and do them properly. Doing these things, especially the overhead (Which is a damned common weld) is, in difficulty, like trying to nail jell-0 to a tree. And guys with little or no education, only experience and practice and an innate ability, do it all the time, every day, all day.
No, welding isn’t a bloody easy thing. Unless you’re doing it on a table.
22 comments Og | Uncategorized
…which is why a good welder will always be employable. A foreman or engineer can tell in the first minute after that welder gets to work whether he or she will be up to the job.
The metal trades are the major trade group I’ve seen where you can’t live on a phony resume. Whether fabbing sheet metal or heavier levels, you have to know your shit or you show up as incompetent REAL quick.
You got that shit right, Dog.
“No, welding isn’t a bloody easy thing. Unless you’re doing it on a table.”
And that isn’t even getting to the materials; welding non-ferrous metals such as copper, bronze, aluminum, or titanium. With titanium the temperatures of the pieces can make the difference between a good weld and scrapping the pieces and starting over.
I’m a great engineer; and I’ve been trained by great welders, but I’m not a very good welder. Oh I KNOW what to do, but being able to do it consistently (and good welding is all about consistency) is another story entirely.
I was trained to weld by a custom bicycle shop, and then a motorcycle shop, when I was a teenager. I got the oportunity to weld a lot of different materials in different conditions, and all in all got a few hundred hours of welding experience… which is about enough to be a not very good guy who can sometimes join two pieces of metal.
The worst hell? Before the master bicycle fabricator would let me even touch aluminum tubing, he made me weld two soda cans together, without holing the metal. That must have taken me four days straight of nothing but trying to do that for eight hours a day.
I tried to do it again a few weeks later, and I couldn’t do it. It’s a skill you must constantly practice, hone, and refine.
A good welder is a master craftsman, and should be treated (meaning respected and compensated) as such.
You can also Velcro, which is how I stuck the light bar to the tiles above the medicine cabinet (actually, the Velcro was adhesive-backed). I couldn’t drill through the tiles.
I believe Steve over at Hog on Ice said something to the effect of “Welding is what they teach people in vocational schools when they’re too stupid to go to college” (I know that isn’t verbatim, but I remember that was the idea he expressing).
What he (and others who scoff at welding being “hard”) don’t realize is, that while expert welding may not require much in the way of “book learning”, it takes the kind of skill that only comes from a rare combination of on the job experience under the eyes of someone who really knows their shit, and the kind of artist’s touch that can’t BE taught.
I’ve taken a welding class at the local community college with a NASA certified instructor. This guy knows his shit back to front. He was honest with we, telling me that I would never be a good welder, because although I understood the technicalities of it better than most of my class, I lacked
“the touch”.
He was right. I can stick two pieces of metal together, but my welds wouldn’t pass ASME standards in a million years. Especially with stick welding (ack). I never intended to be a welder, I just wanted to get good enough to do some simple things and minor repairs, so I got what I wanted out of the class, but it gave me a much greater appreciation of what it takes to do a proper weld.
The people that think welding is easy have never had to try and hit industry standards. Guaranteed.
Best welding I ever did was on a 16×6 hydraulic dump trailer, which I designed and built from scratch. Damn, I was proud of that work. Still am.
Dick, we need pictures.
Grau, that’s why, as steve said, there are “450,000 welders who are sixth grade dropouts” and 85 physicists. Of course,the physicists must be in higher demand. They’re ever so much smarter.
Chris, that’s a damned good story, I remember hearing similar ones at Boeing. I know it can be done, too. I’ve seen a robot cut an aluminum can in three sectins- top, cylinder, and bottom, and after removing the cylinder, reweld the top to the bottom to effectively make a 1/2″ tall coke can. (ND-yag laser). Impressive stuff.
you know what I like about you? The way you take stuff that seems really complicated and make it seem so simple. How about a little primer on the fundamentals of electricity?
Have I mentioned that I weld under a microscope? Current job is .0015″ thick AM350.
but… I wouldn’t have any idea how to begin doing the kind of welding you guys are talking about. Wish I did.
Whaddyawannaknow, Holder?
And yes, jean, I’m amazed by the stuff you do.
Steve’s problem is that he’s used to judging things that one can learn effectively in a classroom. Welding isn’t one of those things. One is an infinitely better lawyer (or physicist) on the day one graduates from the programs which teach those professions than one is a welder on the day one finishes trade school. Experience counts in every area of life, but it counts to a massively disproportionate degree in highly skilled trades (like welding).
That being said, Steve’s ambition is plainly not to become a master welder…it’s to learn how to do basic welding suitable for use in his personal tinkering projects. And that is, to put it politely, a far less challenging standard than the one you lay out here.
The hell of it is that it looks so easy, doesn’t it? Some of those guys will run a bead faster than it takes us to talk about it. All the equipment is different now too what with mig, tig, plasma…what next? Phazer beams?
Even welding the flat stuff is no picnic. Up here in the Alberta Tarsands the pipeliners and welders are going nuts 24 hours a day. They work around the clock, outside, in temps of +35 C in summer to -35 C in winter. Ugh.
I have noticed a dismal character trait to welders too…to them, a piece of work isn’t hot unless their hands smoke when they touch it. Machinists are the same way. If they tell you something is warm….trust me…it’s HOT! If they won’t touch it…neither should you! I learned this wisdom the hard way.
:)
The real masters make a complex task seem like art, indeed.
Ok, so, hypothetically speaking, if I wanted to try to learn welding, what would you suggest? Start out with a course at the local community college?
I worked one summer for a guy who ran a body shop, customizing cars. I never got the chance to try welding but I wanted to.
A community college is a good place to start.
Auto repair welding is tricky business. Most of the welds on body panels, for instance, are vertical welds. Damned difficult unless you have a lot of practice doing it.
You know, people like Steve can sniff at the technical jobs all they want to, because it’s those technical jobs that give them the security and comfort to sniff.
People weld because they’re too stupid to go to college? Please. I guess plumbers are the same way, right? Except in your day to day life, you don’t call a physicist when your toilet backs up. You don’t call an engineer when your AC goes out. You don’t call up a biologist when your car dies on you.
That whole “Oh, you only do job ‘x’ because you’re too stupid to do anything else” smacks of the same elitism that John F’n Kerry displayed when he joked at the stupid people get sent to Iraq.
Og, if I ever get up the gumption to learn welding, I’d probably not do it for auto welding unless I had someone knowledgeable to teach me–I wish they would have taught me back in HS at that job I mentioned on a prevoius comment. I’d probably use it for simpler stuff, of the caliber of the stuff Steve has mentioned.
I’ve been close enough to people doing non-technical stuff: electricians, plumbers, carpenters, auto mechanics, etc., I’d never call ’em stupid because they’re not doing technical jobs. I’m a codeslinger by trade, but I don’t think that makes me smarter.
Somedays I think about having a trade instead, altho at 36 it’s a little late to start. :)
Rick, I became a machinist at 24.I ran an ad agency at 26. I became a robotics technician and engineer at 32. Rememeber, Goethe wrote Faust when he was 57- before that, he was a lawyer. You are never too old to learn something new.
Og,
Sure, I know that. But I’m mostly happy with what I’m doing, and I don’t *want* to change careers if I don’t have to. :) If the need came up, I’d do it.
My plan, such as it is, is to get enough money together to buy a few acres of land, build a mostly-off-grid house, and maybe run a hobby farm.
One of these days I’m going to have to pick your brain over ways to obtain a career instead of simply having a job, Og.