On Tuesday, February 14, 2012 06:49:06 AM Mark Cason did opine: [...] > >> alloys, There's a reason why noble gases, specifically Argon, and > >> Helium are used as shielding gases. The only exception is CO2, where > >> it's used in welding. > > > > There, particularly in a mig setup, its main reason is to add its > > carbon to the puddle, hardening the weld. Same effect as firing up > > your Smith Wrench and running a long central feather in the flame by > > reducing the oxygen flow a wee bit. You can make very very good > > welding rod out of a pile of coat hangers that way. ;-) But you > > don't have the control over the carbon added that way in comparison > > to the Smith Wrench, that is almost unlimited. > > > > Cheers, Gene > > Off topic, butCO2 isn't technically a shielding gas, it is a reactive > gas. Along with increasing carbon content in a weld, CO2 also adds heat > to a weld, resulting in deeper penetration, at the expense of a bit more > slag, and lots of spatter. Using pure CO2 is an old trick to make a > small welder weld like a bigger one. Very thin sheet metal can use pure > Argon, up to 95/5 AR/CO2 mix, but basically, the thicker the metal, the > more CO2 you want. I use pure C02 from 1/4" on up. I have both CO2, > and Argon tanks, with their own flowmeters, and a custom made mixer, so > I can dial in the exact mixture, from pure argon, to pure C02. Getting > the percentages set right is a bit touchy, but it works, and it's a lot > cheaper than proportional gas mixer.
:) > Sorry, I can go on for hours on the various methods of welding. It's > one of the first things I learned when I was very young, and I'm quite > good at it. I took classes from a guy with a 3 foot string of Army/Navy Cert cards in his wallet, back in the middle 1950's. He was good, I saw him use a gas torch to put the pieces of mag back in the side of an early 6 cyl mercruiser block that a wandering con rod had knocked out. Very nice puddles when he was done. Then he showed us, since the block was also warped from a lack of coolant and not rebuildable, what would happen if you got it too hot. Since we were on the sidewalk in front of the building, we had to pour a couple sections of new walk the next day after things had cooled, and had to convince the fire dept, who had never seen a magnesium fueled fire before, not to hit it with any water which would have made it real interesting, real fast. The sidewalk needed replacing anyway, so no big deal. Today, the environmental folks would have arrived the next day with whole stacks of fines for env damages. :) Yes, its a science all by itself. > I have 5 different welding machines, and my favorite is my > 220v Millermatic, but right now, my most used machine is my little > Lincoln 140, running FCAW, because I can take it pretty much anywhere > there's a 120v plug. I have a 135, with the usual argon +25% CO2 mixed bottle for shielding. It works well if I can keep the auto shield from fogging up as I have to pull it down a long way to see through the trifocals. > I have a nice Lincoln Precision TIG, but I don't use it enough to > keep my skill level up. However, welding up Dad's transfer case a > couple weeks ago, really tested the machines ability, as well as my > skill. It hasn't self destructed yet, so I think I did ok. > > As for the coat hangars, I haven't used any since I was a kid, > "borrowing" Dad's torch to fix my bike. Dad would notice when a filler > rods came up missing, but Mom never really noticed a coat hanger > missing. Smith Wrench, never heard that one before. I'll have to > remember that :) Slang I guess since Smith makes the best ones. The electric stick box was a Miller Wrench by the same logic. OT? I'd say... Cheers, Gene -- "There are four boxes to be used in defense of liberty: soap, ballot, jury, and ammo. Please use in that order." -Ed Howdershelt (Author) My web page: <http://coyoteden.dyndns-free.com:85/gene> Never underestimate the power of human stupidity. ------------------------------------------------------------------------------ Keep Your Developer Skills Current with LearnDevNow! The most comprehensive online learning library for Microsoft developers is just $99.99! Visual Studio, SharePoint, SQL - plus HTML5, CSS3, MVC3, Metro Style Apps, more. Free future releases when you subscribe now! http://p.sf.net/sfu/learndevnow-d2d _______________________________________________ Emc-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
