i want to learn to weld...

[Coalsmoke]

What did you mean in the previous story with the cold chisel and caulk?



Dave

I agree, you have got me scratching my head on that one too.

 

[DJW]

DValentine, If I read it correctly you placed a tunnel over the joint? Not seeing the job and conditions under the repairs were done so I many be totally off base. If the laps were air arced where the edge of the plates lapped, new metal on the plate edge and grooved into plate and a fillet weld. If rivets were leaking although not code, edges of rivet heads if snap heads air arced to a groove and welded. Perhaps the original plates were so rust scaled that caulking would be ineffective and if stopped leak would fail later. If you are familiar with a riveted pressure vessel, the rivets are hammered to fill the reamed holes before headed over or spread if flat, (there are a number of head configurations), the contraction of the rivet tightness the space between sheets. When all riveting is finished where the end of the plate meets the shell where one would place a weld it's caulked, a blunt type chisel forcing the seam closed. (like you wife pinching off the top of a pie) The screaming noise you hear in riveted shipyards or being repaired is by use of the caulker. In general a riveting crew consists of a Heater, Catcher, Bucker upper and Riveter, and they work together like a precision machine. You probably know no riveted ship ship is leakproof so I'm told. Just come to me, only the seam on the pressure side needed attention if it could have been accessible

 

[DJW]

Another piece of information (I'm full of the stuff at times) take a look at a square nut seldom seen now, the top side has a slight convex shape the bottom although flat, but look closely seems as if it was formed by a blunt punch as the four corners extend below the main surface of the nut. As the nuts were used during riveting was the main way of fastening pieces of metals, they were ideal for double duty. First, pieces were bolted together to facilitate riveting so the convex side was the first to be screwed onto the bolt, it was because being convex it would break away easily, if they were used to permanently to fasten two pieces of metal together the protruding corners would aid in setting bolt and resist vibration unscrewing as a lock and similar retaining washers, (learned that in the USA) as I was not familiar or that use in the UK.

 

[GHarman]

DJW, Man, you've been around this "Old World". 1926, Eh, I'll bet you know a thing or two about WW-2! My good Friend and Mentor passed away ,October2006. He was involved in the Normandy Invasion, 2 Bronze Stars and a Purple Heart. He would have been your age had he survived.



I know what you mean about giving up old ideas. I have not worked around riveted structures, but I had to build a prototype "X" that was designed by a carpenter turned engineer!! You talk about a non-weldable mess!!

Ever have to convince a "machinist" of the highest quality that their weldable part is not designed to be welded? Metallurgically (machined from free machining steel) and the weld joint geometry is non exsistant!! Wow what a chicken fight that turned out to be. Real "Welding Engineers" and engineers that have an understanding of how something must be prepared if welding is to be undertaken, both from a repair/prototype standpoint and a production standpoint are out there but seem to be very rare in general industry. I have had the priveledge of meeting a few and they were worth every cent the employer paid them!!!



I understand the pinching process you refered to as caulking. Having worked on Natural Gas pipeing, that was one of the many tricks we would use to stop a leak. Sometimes even, hot forging a hole. That is, lighting off the hole with your stinger, welding a ring around the hole getting smaller and smaller till the pressure blows the puddle out, then your helper slams the hot buildup with a hammer. Stops 'em every timeOo. . Yes there is a flaming spout right next to your head. Burnt my beard off, even with my helmet more than once. GregH

 

[rbattelle]

That is, lighting off the hole with your stinger, welding a ring around the hole getting smaller and smaller till the pressure blows the puddle out, then your helper slams the hot buildup with a hammer. Stops 'em every timeOo. . Yes there is a flaming spout right next to your head. Burnt my beard off, even with my helmet more than once. GregH

Wait... welding a natural gas pipeline with the gas running through it!? Really!?



Seems crazy! I hope that type of job pays well!



Ryan

 

[DValentine]

DJW we just built rings over the rivets. 14 inch rings over the lap joint and the rivets on the inside of the penstock. I just don't see much stuff that has rivets today.

Thanks for passing on your information and stories.

D

 

[GHarman]

Wait... welding a natural gas pipeline with the gas running through it!? Really!?



Seems crazy! I hope that type of job pays well!



Ryan

Actually, Ryan, Natural Gas pipelines are welded on as a matter of course. There is no oxygen inside. The oxygen for combustion is mixed at the burner. I have welded Hot Taps on Natural Gas pipe that was pressured as high as 400#PSIG. The real trick was a service tap welded on a 1/2" distribution line that was pressureized to 125#. That is not done so much these days as most utilities use Plastic pipe, heat fused fittings, and lower distribution pressures. etc. However, large transportation pipelines are still steel and require hot taps, stoppers and bypass fittings welded on a pressurized, live main. It can be a very good paying job. There are job specific safety procedures that must be followed, just like any other specialty. GregH

 

[rbattelle]

Actually, Ryan, Natural Gas pipelines are welded on as a matter of course. There is no oxygen inside. The oxygen for combustion is mixed at the burner.

WOW! I know there's no oxygen in the pipe, but there's tons of it after the gas exits the pipe! So there must be quite a flame shooting out the hole you're trying to plug (hence the singed beard)!



Man, you really gotta have a pair to do that kind of work.



Ryan

 

[GHarman]

WOW! I know there's no oxygen in the pipe, but there's tons of it after the gas exits the pipe! So there must be quite a flame shooting out the hole you're trying to plug (hence the singed beard)!



Man, you really gotta have a pair to do that kind of work.



Ryan

Depends on pressure and volume. Once we had a split line and the only way to fix it was to jack a patch on it and weld the sucker on. I have done bypasses for repair as well. Lots of tricks of the trade that you learn as well as T. D. Williamson and Meuller Tapping and stopping equipment. Most welding was done with the old red Lincoln 5P, E6010, with the E7010G HYP rod used as a backup for a tight fixer. Mostly 1/8" and 3/32" for the small stuff. The power Supply was an old (now) Lincoln Pipeliner SA200. Actually, any welder can do this type of work, The Code is API-1104. Certifcations that I had to pass was a 12" bell hole fixed (verticle weld, downhill progression), with a Root bend, Face bend and a tensile pull from each quarter, and a hand fabricated 12" inverted "T" with 2 nick breaks and two tensile pulls. The test took all day if the weather was nice:-laf. If the weather was bad they allowed extra time. These tests were taken off the back of my truck, in a laydown yard, every 6 months. GregH

 

[nickleinonen]

Man, you really gotta have a pair to do that kind of work.



Ryan

good thing the flames are at head height when welding. . a little lower might hurt a bunch more. .



i guess when you are welding on pressurized pipe you need to be real careful in how you setup your machine to not blow through. . i have welded on a pressurized air pipe [before i knew better] and it burnt through it like arc air. .

 

[GHarman]

good thing the flames are at head height when welding. . a little lower might hurt a bunch more. .



i guess when you are welding on pressurized pipe you need to be real careful in how you setup your machine to not blow through. . i have welded on a pressurized air pipe [before i knew better] and it burnt through it like arc air. .

Lots of stories, but the main thing is your travel speed. You cant pause for any length of time on the smaller pipe cause the wall thickness is only schedule 40. We started out Oxy-Acetylene welding service taps on distribution mains that were pressurized below 50#PSIG and 2" nominal I. D. Man you got to move! One catch in yer git-a-long and you got a burn through. Thats when the man with the SA200 shows up and does the hot forge trick:-laf.

BTW, I've had my trouser cuffs catch fire as well as my beard burned off even with my welding helmet. I never sustained a burn from the Natural Gas. I once burned myself with the Oxy-Acetylene torch, that was my fault. It still hurt like H E, double hocky sticks. GregH

 

[DJW]

GHarman, owing to my age I missed D-Day, a friend I went to school with from Infants, Elementary and Tech, he was in the first British wave, also another boy I knew in another village my parents moved to. They were in the same regiment but unsure if they knew each other. The both were wounded and brought back to UK as too early in France to treat. Each thought it fairly mild, and even years later seemed not to have been affected, in fact the one from the village said he landed with 200 French Francs and a packet of Condoms, (British call them French Letters) but he was laughing as he said walking ashore waist high in water everything was soaked. After the War he joined the London Metropolitan Police, then joined the Police in Kenya where he retired from. Aside from a little heavier, he hadn't changed at all, same smile, laughter, speech just as I first knew him at 72 years of age. If you can, or even find you can find it try and read about the American's D-Day, I did know of the heavy losses, but not for the reason it was.

 

[DJW]

I was working in the Geothermal steam field in Sonoma county California and there was a steam pipe coming out of the well and was vibrating, so I was told to find a steel plate and weld it to the pipe and to the outer casing to secure it. Was warned to not burn through as the steam was at 550 lbs. pressure and no way to turn it off. I weld it to the pipe first, by doing so could use my foot against plate to keep it firm against the live steam pipe, thus would not have the concern of weld parting from plate while still molten, so that welding to the casing was no problem. Just spend the time to figure out all the angles, that "Do it even if it's wrong" is shear Stupidity, but sadly the norm on many jobs.

 

[GHarman]

DJW, "Do it even if it is wrong", is , sadly still around to haunt us. It is usually ramrodded by a forman or manager that does not know or care about the work or the worker, just do it "so I can get the credit". Then go back under a maintainence work order and fix it over and over. I ran into that while working for the Gas Utility. Never mind the root pass, just butt'em up tight and weld'em so they dont leak. I said, "not me"!!! I'll do it right or I'll drag-up!



When I did leave that company in 1982, I had the satisfaction of knowing that all those people that thought it was so easy to be the Lead Weldor, bid on the job and could not pass the welding test. They had to bring in a weldor from the Denver Shops.



Yes, Steam could eat your lunch if you would have burnt through. I dont remember the temperature to pressure ratio, Id have to look it up in my "Frankland" book but it would have been around 600*F. @550#. Nothing to mess with. Uncontrolled Steam is not your friend!!!! I'll bet that shaking pipe gave you some built in oscillation:-laf. Congratulations on that weld!!



On the same note as your steam, I was asked to weld a hot tap on a gas well head so they could check pressure. I asked, "what is the historical pressure at this well head"? "I dont know", was the answer. How thick is the casing? "I dont know" was the answer! I said "Not me, Bud"! "My Mama had a Baby, Not a FOOL"!GregH

 

[GHarman]

Steam temperature vs Pressure

For those that are interested, here is a Steam Entropy discussion with the formula to calculate steam temperature at a known pressure. Charts are available elsewhere. This is for those of us that like the math:-laf. GregH

Steam Entropy



PS. Temperature is Absolute and in *K not *F. Ya got to do some conversions.



A correction to my reply to DJW. Steam @ 550# is approximately 477*F. According to steam tables. My SWAG was not correct, my memory flawed. GregH

 

[GHarman]

Steam Tables

Here is a real thorough rundown on steam. Hey Dave Valentine, what do you think of this? GregH

www.powerplantserviceinc.com/steamtable.pdf

 

[DJW]

GHarman, I was more concerned with burning through at the time, but knowing the temperature is essential for many industries. When going to Sea as a Coal Burning Fireman, (in the Dark Ages) I was in the engine room and the engineer was checking out all the gauges etc, and called out the temperature of the steam, I told him he was wrong as water boils at 220* F, he corrected me with At Sea Level, (not sure if 220 or 212 now). I was just thinking back to Physics. As you can sure Bet, I never Bet. (found it too costly at times)

 

[DJW]

GHarman, I believe the poor quality of foreman etc, Hurry-up hurry-up started during WW2, for instance if you had to maintain output and only had a certain group of men, who would you pick to keep time records, allot work, see to supplies etc. essentially the less skilled the obvious choice, plus the least productive. Plus the feeling of superiority over people of much more skill and value, that establishes a breed. I have noticed the most difficult welding inspectors are those welders who couldn't make it in the trade. The yo-yo kind, first to be laid off and the last to be rehired. Not all are like that but often the difficult ones are. In general that also goes for all the trades. Often where I worked if the job had a beef, (squawk sheet) and wouldn't be signed off I was often sent to correct it, seemed I got on well with the inspectors or whoever had the beef, as I found if one respects another's view things could be worked out, I had seen others in a shoving match and neither could find common ground.

 

[GHarman]

DJW, Humble is the tactic that always worked for me. I learned early on that there is always someone that can teach me a trick or two and as long as the LORD gives me breath, there is something to learn.

I have a Good Friend, in his late 60's that still works as a CWI. He is a hard nosed Cowboy. However, If you listen and try to follow his instructions, with no disrespectful attitude, he will teach the weldor a few things. This man has been welding since he was a teen. On His last job, he certified on all the processes being used before they found out that he was qualified to be a CWI. They transferred him over to that capacity Quick as a wink. He was instructing as well as Inspecting and one of the foremen challenged him, "your not qualified"! My bud said, "OH Yes I am", and showed him his Certs.

There was some jealousy there! This man could do what he required of everyone else. Matter of fact, two of the Senior inspectors had repeatedly taken the AWS, CWI exam and repeatedly failed it. Talk about politics and being promoted to their highest level of incompetence

I am also familiar with the "Good Ol' Boy" Clique. I was not in that group.

GregH

 

[DValentine]

As I was learning about steam in my apprenticeship I was amazed to find out that at 3206. 2 psig and above steam is so hot that it goes from liquid to gas instantly. I am not a math whiz so crunching numbers makes me numb. But the power of steam on a level such as a tea kettle compared to a super critical boiler (one running over 3206 psig) just makes my mind spin. The ones I have worked on a great deal are sub critical 750 megawatt boilers that produced 4,559,000 pounds of dry steam an hour. I didn't understand dry steam when I first heard it. How can steam, coming from water, be dry? You separate the water droplets and then heat it again.



DJW, I got a chuckle out your comments on weld inspectors. I agree.



edit..... Ok Greg, I don't want to sound like I am stereotyping. Ego is the downfall of many men, on all levels. When I start to get a big head... . the Old Man makes sure I see the errors of my ways.

DV