[Alexa]

correct me if im wrong but isnt hydrogen highly unstable, the same reason why automobile companies wont use hydrogen to power the automobiles instead of gas. by compressing that into a gas cylinder would make the risk even higher if something was to happen inside of a shop? say if something happened to the compressed gas cylinder? im not saying the mixture wouldnt work i would just be concerned about having any form of hydrogen in or anywhere near our shop.

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Welderkid556.

Found this brief information concerning the safety of hydrogen on page 62 of the following link.
http://www.awssection.org/uploads/longi ... Manual.pdf

"... HYDROGEN DANGER

Hydrogen is a flammable gas. A mixture of hydrogen with oxygen or air in a confined area will explode if ignited by a spark,
flame, or other source of ignition. A hydrogen flame is virtually invisible in well-lighted areas. Hydrogen as a liquid or cold gas may cause severe frostbite to the eyes or skin. Do not touch frosted pipes or valves.

Always use a pressure-reducing regulator when withdrawing gaseous hydrogen from a cylinder or other high-pressure source.
Take every precaution against hydrogen leaks. Escaping hydrogen cannot be detected by sight, smell, or taste. Because of its lightness, it has a tendency to accumulate beneath roofs and in the upper portions of other confined areas.

Do not mix hydrogen with other gases from separate cylinders. Always purchase hydrogen blends ready-mixed. ..."

Alexa

[noddybrian]

In the UK hydrogen in cylinders is available & although it's not commonly used yet BOC are unable to provide acetylene here since both bottling plants suffered incidents they are having to buy in acetylene from Air Liquide in France & although their part of the same group they state they are going to phase out acetylene completely & it's suggested that hydrogen will replace it for oxy - fuel cutting / welding. This is not a new idea - a long time ago I'd used hydrogen for cutting underwater - don't think they still do as there is oxy arc / thermic lanse & probably other methods now.

Sorry to side track this post but when oxy / acet was easy to obtain & cheap a company made a thing called H2O-2000 ( or something like it ) basically just a big mains powered HHO generator which was grossly over priced & never caugh on - but with the supply issues & cost of gas now does anyone know if there is anything like it still around - if so has anyone tried it - was it any good - or better yet does anyone know how big the plate stack was in it as it would not be rocket science to make one.

[welderkid556]

i thought hydrogen was pretty flammable lol. ive used accetline for cutting but i use propane now and it works just fine for cutting steel, just today i cut a peice of 1/4 inch steel and it cut right through it with no problem, but im sure it would cut through half inch and possibly even 3/4 inch steel. i may have to try it but i know propane seems to get the steel pretty hot before you can blast through the steel. it seems with accetline its a more mellow way to cut steel and doesnt take half as much heat. over in the UK can you get ahold of propane or have they gotten rid of propane aswell as accetline?

[noddybrian]

Sure - you can get propane here - alot of people use it - more for heating than cutting - ir's obviously not as hot or concentrated a flame as with acetylene but is adequate for most free hand cutting - never seen a profiler use it though - cuts are never as clean - it's also alot slower getting initial heat into the job & you will use more oxygen per similar amount of cut. acetylene is currently still available but as it's having to be imported the price is awefull. not sure what maximum thickness for hand held cutting is - obvioulsy it's in proportion to nozzle size & cutting pressure, but I routinely cut upto 4" by hand - when cutting any amount over say 1" though I usually swap to a longer torch as the amount of hot metal & general heat from the job gets a bit much - depending on the job I use 12" necked torch for small odd jobs & easier control then I have 24" & 36" torches in regular 90degree 45 degree & a straight one I keep mostly for cuttting sheet piles in situe.

[Otto Nobedder]

I once worked at a plastics manufacturer, and used a hydrogen-oxygen torch on a regular basis.

I now work almost exclusively in the LIQUID hydrogen transport industry.

It's safer than you think.

Steve S

[welderkid556]

i am slowly upgrading my equipment such as tanks and hoses that are longer and such. i found a torch that looks pretty heavy duty and its made for propane cutting, its made by smith equipment. its a very nice chrome plated torch and regulators. we used smith cutting tools at my last industrial shop i worked at, we used a big propane tank with 3 big oxygen tanks around it and i worked at that shop for around 2 years and we very rarely changed out the big propane tank because it ran out. the entire time i was there i think we changed the propane tank like 3 times. but the big oxygen tanks we changed them almost weekly with all of the cutting we did. we used it more than our accetline torch, we got good enough with propane we even forgot that we had an accetline torch, someone covered it with a welding blanket. i think eventually the foreman exchanged the accetline tank for an argon tank since we never used it. here in my neck of the woods(literly)woods lol, i have never even heard of hydrogen cutting, never knew such a thing existed, is it cleaner than propane and accetline cutting?

[Otto Nobedder]

Noddybrian,

I've never done it with with propane, but I've used a pipe beveler with oxy-natural gas. Not as smooth as acetylene, but smooth enough. It was a steel-mill shutdown, and there was natural gas and O2 piped everywhere, so it wasn't economical to use acetylene. It took me a "minute" to get used to starting the torch, but after that, the only issue I had was slower cuts with a little more dross to clean up.

@ welderkid,

I've never cut with H2/02, but I'd expect a very clean fast cut with a narrow heat-affected zone.
The problem with hydrogen is leakage. The only thing in nature smaller than a hydrogen molecule is a helium atom, and it will escape from any system that isn't nearly perfect. Hydrogen is explosive/combustible in air at concentrations as low as 4%

Steve S

[Braehill]

There's an interesting site called weldreality.com I believe on the subject of welding gases for Mig. I can't speak to subject of spray transfer first hand. I just bought my first Mig welder this year and have a total of about 24" of experience. I can add a little bit to the conversation about Hydrogen though.

You can add up to 4% Hydrogen to argon and safely weld with it. It has a LEL of 4% and a HEL of 75% (Lower & Higher Explosive Limit, respectively). This is not something you should do with the gas mixer you have in your weld shop though. All the piping should be socket welded s/s or high pressure s/s compression fittings to try to be 100% leak free.

You would be suprised to know where all Hydrogen is used in industry. Because of the tiny size of it's molecules it can flux out impurities in metals and semiconducters and such. This small size also poses the problem of keeping it in a piping system and remain leak free. It's easy on Steve's end of the spectrum because @ -424F there is not alot of space left in between the grain struture in a s/s pipe for it to escape. Pump it up to 2700 lbs @ atm, and you find leaks everywhere.

Len

[Otto Nobedder]

Len,

You'd be stunned at what we found when rehabbing two "extreme-pressure" pumpers, modified to pump gas at 5000+ PSI to fill CG tubes.

The modifier was supposedly held to x-ray, at 10% random. After the first two turds we found, we called in a radiography crew, and 95% of the high-pressure piping (sch. 160) FAILED HORRIBLY. We cut out every inch and reworked it. It was stunning that none of those "welds" failed.... Most were flat-butted pipe with a crown weld.

The films went to HQ. Those folk are not likely to be doing modifications like this for this company any time soon.

Steve S

[sunppeli]

I'm interested in trying out spray transfer migging. I have an older 315amp Esab MIG/MAG and using 100% CO2 atm. I guess the way to start is to up the current, lower the wire feed and try to keep a tight arc to up the voltage? Will I have any luck with 100% CO2? I also have 100% argon for my tig? I guess that's no good either.

Thanks for any tips!!

[rake]

I'm interested in trying out spray transfer migging. I have an older 315amp Esab MIG/MAG and using 100% CO2 atm. I guess the way to start is to up the current, lower the wire feed and try to keep a tight arc to up the voltage? Will I have any luck with 100% CO2? I also have 100% argon for my tig? I guess that's no good either.

Thanks for any tips!!

If you up the current and lower the wire speed all you're gonna do is fry tips.
Up both. With the high current you'll need high wire speeds to keep up to it.
Most times on carbon steel we ran 90-10 ar-CO2.

Jack the voltage up and crank the wire up so it shunts and spatters like crazy.
now lower the speed slowly till you get a smooth hissing sound. Once you get to the
hissing you're in the sweet spot.

[Otto Nobedder]

I accidentally achieved spray-arc with 75/25 gas, much to my surprise.

My goal was high heat input with little metal transfer, as I was removing bearing races. The goal was to induce shrinkage in the races with the minimum of spatter, yet not roasting tips.

I wound up at 31V and 380 ipm (.035 E70S-6), and the arc went silent (earplugs in). Since I was welding 3G (minus the groove, just on the face) a lot of droplets fell out of the puddle, but it was not spatter and stuck nowhere. The heat input and shrinkage were perfect, as I was able to "drive" the races out by tapping them with a drift punch, no hammer required.

I rarely weld carbon steel in a flat position, but I'll remember these settings... I'd think a 1G done this way would look slick! I also have the option of 100% argon, and might try it with tri-mix just for the hell of it.

Steve S

[Oddjob83]

ok so, when i was taking my course for MIG flat, our teacher had told us that our root welds were spray transfer and the rest globular. I practiced between classes at work and i had basic 75/25, and got the same results as at school, even had the same machines too, so it was very easy to get in extra plate practice.

Now with my gas mixture and using 25v and 475wfs we got what he told use was spray transfer, very clean and highly penetrating welds, sounded like static on your TV when you get no signal.

Before he actually got around to showing me how to do it right(i was 2 hours late cause of daylight savings) I had my contact tip 1/8 beyond my nozzle and was practicing on scrap. I was blown away at how i was getting such a beautiful highly penetrating bead and was like pouring glass out of the gun and no more noise than TIG on SS. then after 12" my contact tip turned grey and wilted like a rotten banana or a flaccid member it was pretty embarrassing especially after it happened a 3rd time and he couldn't tell me what i was doing wrong. he blamed my torched tips on the fact that that day i was on a LE 256 that had extra featured like 2T/4T enabled and crap. I found out what my real issue was though (contact tip out too far and too close)

anyways sorry for the bore story but this is my only real experience with spray, and by the sounds of other testimonials I couldn't properly achieve spray unless I am using a higher quality gas mixture than 75/25. My teacher wasn't the most, um, "all there" so maybe he was telling use one thing and meaning another. Like when he makes a statement of "anything above 24v is spray transfer"

so was what i was experiencing before my tip melted what Spray supposed to be?

[Otto Nobedder]

Your description of "static on an empty frequency" sounds like globular transfer. It does have some noise.

Spray-arc literally sounds like a gas leak... It hisses, quietly.

I commented because I've been told you can't achieve spray-arc on 75-25. Most MIG sources aren't capable of 32V at 300A, though.

I found, at 3/4" stickout, the wire would "vaporize" about 3/8" from the surface, and I worked this way for almost two hours without melting a tip.

Steve S

[Oddjob83]

yea that was the weird part about my gas mixture confusion too, as, from the same teacher in a intro welding course had told me that spray arc was not usable unless you were using a premium gas and his example "Mison". but then when i was taking my ticket courses, he tells us that it is not necessary at all and say that i am wrong in suggesting so, and gave me a "are you daft" look. embarrassed me quite a bit as i got 99.9% in both classes and took notes meticulously. Perhaps he felt like taking me down a peg or something, i personally think he hasn't learned anything new in the last 15 years as far as welding goes.

[Otto Nobedder]

yea that was the weird part about my gas mixture confusion too, as, from the same teacher in a intro welding course had told me that spray arc was not usable unless you were using a premium gas and his example "Mison". but then when i was taking my ticket courses, he tells us that it is not necessary at all and say that i am wrong in suggesting so, and gave me a "are you daft" look. embarrassed me quite a bit as i got 99.9% in both classes and took notes meticulously. Perhaps he felt like taking me down a peg or something, i personally think he hasn't learned anything new in the last 15 years as far as welding goes.

Remember, from "Peanuts",

"Those who can't "do", teach..."



Steve S

[Oddjob83]

Funny enough, a few of us other "baffled" students said the same thing after a particularly arduous eye-rolling session.