and the moon is made of cheese:)
"This was my in reply, with a couple of grammar corrections, to a similar question that was asked in a different thread.
Hello Joe;
I read the other post where they were discussing "where does the water come from?" Interesting, very interesting.
The water is a byproduct of combustion. Whenever you burn a hydrocarbon, you produce water (H2O) and carbon dioxide (CO2). I don't care if you burn wood, natural gas, or acetylene; the end products include H2O and CO2. Sorry I can't make the numbers subscripts.
We did an experiment in Physics class once where we had to calculate the BTU (heat) content of natural gas. We placed a Bunsen burner in a dish and placed both under a boiler. We measured the flow of water and recorded the inlet temperature and the outlet temperature. We also measured the volume of gas being burned. Several of the students requested new boilers because their dishes were rapidly filling with water from their leaking boilers. The professor just laughed and turned to me; he called me "his little dummy welder", and said, "Tell all these smart people where the water is coming from."
They didn't believe all that water could possibly be coming from the combustion of the gas, but let me assure you, it did. 26 pounds of acetylene produces about 18 pounds of water that condenses on the cold surface during the combustion process. If you were to keep the base metal surface below the dew point, as we did with the boilers, you would not see the "wet spot" disappear. Think of the warm moisture laden air condensing on cold water pipes in the summer.
I don't know where you live, but here in New England, on cold winter mornings water runs out of the exhaust pipe of our cars and trucks until the exhaust system heats up. Every gallon of gasoline produces about a gallon of water when completely combusted.
So, now you tell me, is it a good idea to use a propane fired gas range to store low hydrogen coated electrodes on a field site? What is the burning fuel producing? Are the electrodes exposed to the gases produced by combustion? What's the difference between steam and water?
I was preheating a heavy column in the field in early February many years ago. Once the column was heated, I turned the flame down low so that I didn't overheat the column, but did maintain the preheat temperature. By the time I had the column welded, I had an icicle hanging down in the web that was about three foot long. The foreman accused me of melting the snow off the roof some five stories above my head. No one said you had to be the smartest man on the job to be the foreman.
How many times have you been told to drive the moisture out of the steel before welding? I've heard it many times. Then, once the part is heated, the welders go on coffee break or off to lunch and then resume welding without reheating the part. After all, they already drove the moisture out of the steel. Meanwhile, I get my butt chewed for wasting gas and time trying to "stay warm" as I maintained the required preheat temperature. I never told the foremen they were idiots or dumb as rocks. I just collected the overtime repairing everyone's cracked welds. The wheelbarrows were full and heavy, but the bank never once refused the money.
As for the steel absorbing moisture; think about it, how thick is a beer can? If the steel (or aluminum) was porous we would not be able to buy beer in cans. The beer would leak out. If steel was porous, you would never get me into a submarine. The water molecule is rather large. The pores in the steel would have to be large enough to accommodate them. We wouldn't need screens for our windows, we could use quarter inch thick plate! Ok, ok, I'm getting carried away, but you get the idea."
the above quote was from the last thread on this topic from 803056,
sorry to steal your thunder with your own thunder Al but this topic really gets to me how so few people are willing to accept science and insist on their voodoo approach. it scares me further to think of other topics that are equally simple yet equally 'controversial'.
even with this above quote there will still be fish for all you fishermen out there.
darren
Darren
I agree with you. I was amazed and dismayed at some of the answers during that last string!
I started out in this string, by asking Mr. Prassad; "I hope you are not referring to burning the moisture out of the pores in the metal with an oxy-fuel flame! Please tell us you are not saying that?!?!?! "
I then clarified my question.
"Do you believe that there are pores in metal that you can burn moisture out of, by heating with a torch? Do you believe that the water you see on a piece when you are preheating it with an oxygen fuel torch is the result of moisture being forced out of the metal?"
I still did not get a responsive answer. Instead, I got a private message; "cant believe ......... I thought you were a guru .... I dont think ur a qualified engineer"
Al Moores "Isn't it?" is a private joke. We were both at the Certification Committee meeting in Pittsburgh PA, when this string was running. I introduced a motion that asked that a fourth examination be added to the CWI exam, consisting of the following three questions; Question #1 "Do you believe that there is moisture in the pores of steel, that you can burn out with an Oxy - fuel torch?" Question #2 "Do you believe that there is moisture in the pores of steel, that you can burn out with an Oxy - fuel torch?" Question #3 "Do you believe that there is moisture in the pores of steel, that you can burn out with an Oxy - fuel torch?" If you get any one of these three questions wrong, you can never, never, never, never, never, never become a CWI. Al Moore Seconded the motion.
However, I am sure that there is someone out there who can prove that there is some cast iron, or HIPed metal that has pores in it. And - Of course there is always Ferromanureium and Unobtanium, which everyone knows is full of pores!
I am not an expert on STMs and SEMs, but I would also ask the STM operator how he managed to look at a molecule of water in the high TORR vacuum of an STM. I also wonder how he managed to etch the hole in the 3MM Diameter target specimen. (However he is on the right track abouit the diameter of a water molecule versus the interstitial space dimensions in A-36 Steel.!)
This belief that you are burning the moisture out of the metal is very disturbing. What's next?????? I know!!!! - Flat Earth!! Well, at least where all 385 pounds of me stands!
When I was a little kid [2nd grade] I had an interest in chemistry. My dad set up an electrolisis of water experiment using a battery charger. [This breaks down water into hydrogen and water for anybody not familiar with the process] I knew that if You mixed them together You didn't get water, but that the mixture was explosive explosive. In 7th grade I asked the science teacher how You get the hydrogen and oxygen to combine into water. [never thought to ask Dad] The teacher's answer was "with a spark". DOH!
Joe,
Pls tell me when in all my post did I say there are pores in metal . In damp humid climates there is condensation of water . You dont have to be a rocket scientist at NASA to know this.
You are asking me this question ..........
Ok I will give a small example what i would give my daughter
Take a chilled beer doesnt matter whether its a can or glass bottle . In a place near the sea where the humidity is high what happens when you keep this chilled beer on your table . There is water condensing around it. where does this water come from. Is the can or glass porous Joe . Is it beer from inside the can/ bottle or ..... ? you can add this question to the CWI exam
Prassad
Here is what you said that set my alarm off;
"HSLA steel A572 Grade 50 has a yield strength of 50 ksi. As per ASM No preheating above 70F (20 C ) is required for plate thickness upto 1 1/2 inch(38mm) and yield strength upto 50 ksi when low hydrogen electrodes are used. If conventional electrodes are used the preheat is 150F.This is assuming the temperature of the base metal is at least 20 to 40 degrees centigrade. Good practise would require warming the surfaces of the work to drive off moisture especially in humid atmospheres.
Following completion of a low or medium alloy weld it is generally necessary to heat treat the weld to prevent crack formation.This is done by relieving stresses and by softening the weld metal and weld heat affected zones employing a stress relief or post weld treatment.The temperature for heat treatment and length of time at temperature depends largely on composition of the weld and base metals and section thickness. The preheat temperature and number of passes also affect postweld heating practise"
I wrote back and said;
"I hope you are not referring to burning the moisture out of the pores in the metal with an oxy-fuel flame! Please tell us you are not saying that?!?!?! "
This question was misconstrued by subsequent readers, so I clarified the question. I said; "I am refering to the removal of moisture from the metal. Do you believe that you are burning the moisture out of the pores in the metal? I am not refering to the removal of standing water on a piece of metal."
Again there was either confusion or obfuscation, so I again tried to clarify my position. I asked; "Do you believe that there are pores in metal that you can burn moisture out of by preheating with a torch? Do you believe that the water you see on a piece when you are preheating it with an oxygen fuel torch is the result of moisture being forced out of the metal?"
Now, You still have not answered my direct questions. ARE YOU GOING TO ANSWER THOSE DIRECT QUESTIONS????? DON'T GIVE ME AN EXAMPLE THAT YOU WOULD GIVE YOUR DAUGHTER. EITHER ANSWER THE QUESTIONS DIRECTLY AND SUCCINCTLY - - OR DON'T ANSWER IT.
FYI, I am not a GURU, I am not an Engineer. I am one of the few welders who doesn't say F---ing ot A---ole when I say the word Engineer. I am one of the few welders who has respect for Engineers. THERE ARE EXCEPTIONS, however.
Joe,
For the last time . I am not trying to be a smart a.. . I told you so many times the information is from ASM the references are there if you have a problem you can contact them and resolve it .
As for me I believe what they say and practise it . We always warm our plates in the morning before welding ( Dew formation ). And this has been done for donkeys years at our shop .
I gave the example of the chilled beer can because I feel it is simplest way to explain the phenomena of condensation because in this case you can actually see and feel the water which has formed from water vapour in the atmosphere .Thats how I teach my children trying to give examples which they can visualise . I did not mean to upset you or compare you to my 7 year old daughter .
By the way are you actually involved in CWI certification activity ...... You do not belive in pre heating / warming of plates in humid atmospheres , Why vaccum pack electrodes , pre heat electrodes for that matter . If there was no moisture in air there is no no need for any of this . I am surprised Joe . Who hired you for AWS committee work ? If this is the standard of people setting the AWS exam I will never renew my AWS membership.
maybe we should bring up fundamental creationism vs evolution to get some really entertaining responses. oops i guess i just did.
i think that prasad is unreachable but does provide a very good example for us to remember when dealing with the world. if an "educated" person is so argumentative and resistant to a provable and repeatable scientific truth then we must develop strategies to get around such obstacles to get the job done correctly. no disrespect intended prasad as it is a fundamental axiom of free speech that we have the right to be wrong.
i think that the question of where the water comes from is a great litmus test for applicants for any position within our industry and i will forthwith ask it of every person i deal with within the industry so as to gauge how to treat the other opinions they render.
darren
p.s. i can only imagine how frustrating it must be for qualified and intelligent engineers to have to try and get the truths of science actualized in manufacturing.
Not to change the topic, [but maybee We should] I think I recall reading that aluminum oxide is porous, and can trap moisture, another good reason to be sure it is all removed [before welding aluminum].
Prassad
I don't believe you are in India. I don't believe you are an Engineer, or that you have a child. I think your obfuscating answers point to you being an incumbent politician in
Washington DC.
Hey Joe Bob......Nice....!
i knew that where ever the pot was being stirred you would show up sourdough. real welder instincts attracted to the heat.
how is your court battle going?
darren
My dear friend Joe ,
Contact me on this number 0091 9820084001
I am not sure what any one is trying to say in this string anymore but I would like to point out that when resistance heating pads are used to preheat work we have seen moisture form on the surface as the temp raises. I guesss it came from the plant where the electricty was generated. Unless it was nuke then what?
Copper wire is rich in pores. :>)
I want joe to speak to me
You didn't answer my questions Yes / or / No. How do I know you are not telling me to call the Bollywood equivalent of a $100.00 a minute Sex talk line? I asked specific questions, and asked you to answer them succintly. If you do not want to answer the questions, which is your privelage, So Be It!
You have already made it quite clear what you think of me. What could I possibly gain by calling you?
You would get one heck of a phone bill for one thing Joe.
Once again, I do believe the differences in culture and language are clouding the lines of communication.
Simple chemistry tells us that the combustion of a hydrocarbon produces CO2 and water and heat. The moisture condenses on the cold surface as water. It doesn't matter if the cold surface is glass, copper, or steel. If the surface temperature is below the dew point, moisture will form.
As for the electric resistance heater, I haven't seen moisture form on the surface during use. If my memory seves me correcly, I have seen moisture form on the surface of a bridge girder using gas fired radient heaters that were in intimate contact with the component being heated. Once again, I attributed it to the by-products of combustion.
In the case of aluminum hydrate, I believe you would have to do more than heat the surface of the aluminum to a typical preheat temperature to break the chemical bonds of the hydrate atoms. By the way, why are you preheating aluminum?
When I'm teaching class of welders, engineers, or inspectors, I always try to give practical demonstration. It isn't always possible, but it is fun when you can.
I would like to try "p's" beer can experiment with a sensitive scale to prove that the moisture on the outside surface of the "beer" can is from condensation of the moisture ladden air by detecting an increase in the weight. If the moisture was truely from the can's content, the weight would be unchanged until the outside moisture from the "leakage" evaporated. If I read "p's" response correctly, that is what he did, without the benefit of scale, when performing his magic trick for his daughter.
If any one is "fishing" while dancing, I believe "p's" holding the pole while he's doing the jig and we're the fish.
Thanks for reminding me of my college physics experiment.
Gotta go.
Best regards - Al
803056 If You were refering to My mention of aluminum oxide being porous, I made no mention of preheating aluminum, and never bothered too Myself, but I understand that it is aplicable on heavy sections at times. What I did say is "another good reason to be sure it is all removed [before welding aluminum]" refering to the oxide layer.
Hello Dave;
You mentioned aluminum oxide, I mentioned aluminum hydrate as another potential surface contaminant. Call it free flow thought or what ever you want. I added the mention of preheating aluminum because I've heard other welders talk about removing moisture from the hydrate by preheating the aluminum member. I am simply stating that if hydrates are present, preheating isn't sufficient to break the chemical bonds.
I asked why are "you" preheating aluminum, the "you" being welders in general. The point being that heat treatable aluminum alloys are time at temperature sensitive, that is, they over age when held at elevated temperatures. This affects the mechanical properties in bad way.
Don't believe for a minute that I am "attacking" anyone or taking issue with a response or respondent that takes the time and effort to reply to a question. I may not always agree with the position taken, but I don't believe it serves a useful purpose to degradate the response. (OK, maybe mild "jab" here and there) We all have our opinons that are the result of our experience, training, and readings. They may be right or wrong, but it's only through open discussion that we all learn. I am freely admitting that I may not always be right, but I offer my opinion for what it's worth. Since no one is paying for the advice given, I guess that is about what my advice is worth.
Best regard - Al
