using nitogen when brazing

[jonc5553]

Never used nitrogen before while brazing.
Say you are replacing any part on a system and say you have two joints to make, do you just hook up nitrogen and let it feed in while brazing? And when you are making up that last joint where does the nitrogen blow the contaminates out of system. And how much pressure do you feed in? Explain in detail please, I'm a little slow LOL

[james10]

You should purge ofn at around 2psig when brazing letting the ofn go round the full system when it comes to the last joint open a schrader or service valve on the system if you only have one connection you can use a line tap valve or dont purge on the last connection, using ofn does not blow out contaminants out of the system it displaces oxygen and prevents oxidisation on the inner walls of the tube the difference is extreme cut open a purged joint and a non-purged joint you'll be suprised

[Makeit go Right]

Useful vid:

http://www.youtube.com/watch?v=3uP-eb8Zz08 (http://bluesplayer.co.uk/youtube_wow/video/3uP-eb8Zz08/Brazing-with-Nitrogen-vs-Brazing-without-Nitrogen.html)

[andychill]

OFN makes one hell of a difference to the internal surface of refrigeration grade copper when brazing, Jon. Not looked at the video link, but I've cut open an OFN joint, and a non-OFN joint after a test braze. The difference is staggering.

Don't be fooled by the techno's who'll have you believe that handling OFN needs a qualification in quantum physics. It's no more hazardous than a pub cellar CO2 system. Make sure you have the right guages (dedicated OFN set - NOT LINE GUAGES!!) and treat it with respect.

Using it will result in a super-clean system which will massively reduce the chances of premature comp failure, and outstanding strength / leak testing results that only a fool would ignore.

[RSTC]

I'm so glad someone else asked that question. Thanks

[jonc5553]

Watched video. Thanks alot for responses

[james10]

QUOTE FROM ANDYCHILLS POST!!!!!!!!!!!!
" Don't be fooled by the techno's who'll have you believe that handling OFN needs a qualification in quantum physics. It's no more hazardous than a pub cellar CO2 system. Make sure you have the right guages (dedicated OFN set - NOT LINE GUAGES!!) and treat it with respect."

People are often fooled by N2,if you breath in a single lung full of nitrogen you'll hit the floor stone dead, some of the larger companies including many petro chemical sites have banned it's use for purging etc,Also in some parts of the worl it is being considered to be used for exocutions replacing toxic gases and the leathal injection

[Spare Parts Man]

...also don't turn off the flow until the joint has cooled. Oh! and use a large flame rather than small one as excessive heat will likely result in a porous joint...

[Peter_1]

Never used nitrogen before while brazing.
Say you are replacing any part on a system and say you have two joints to make, do you just hook up nitrogen and let it feed in while brazing? And when you are making up that last joint where does the nitrogen blow the contaminates out of system. And how much pressure do you feed in? Explain in detail please, I'm a little slow LOL
The nitrogen doesn't blow out the contamination out of your tubes. It only prevents carbonizing the inner side of the tubes.
You don't need any pressure - in fact a pressure isn't allowed - you only need a steady flow, the lowest flow possible once the tubes are full of OFN.
You need a pressure regulator which regulates a flow and not a pressure (a flow of +/- 2 l/min is more than enough.
In the Belgium certification (En378/2008), you must prove that you can make solders (phosphor and silver brazings) without a black inner wall. If we find one black spot due to oxygen infiltration, you can come back for this part of the exams.
If you have a warranty case with Daikin compressors and they find carbon from soldering in the compressors, your warranty will be void

[old gas bottle]

thats a bit rich from dakin who make a crap product and blame a bit of carbon for making a rubbish compressor fall over. sorry peter.:D

i allways use nitro ,but care is needed not to over do it as it will make pin holes that can be a pain to rectify.

as peter says, flow over pressure.;)

[Fri3Oil System]

Hi,

In Spain, many companies now are welding without N2, and then, they flush with any gas, (R22 for instance) and eliminate all the debris and carbon.

It looks the results are quite good... maybe we'll have to make another video.

regards,

Nando.

[old gas bottle]

thats the old way, NOT ACCEPTABLE now,against the law and industry standard. why would you want to blow the crap out when you can stop it happening to start with?, plus once the pipework is carbonised theres no way of getting all of the contamination off the inner pipe surface and it will find its way arround the system and cause problems sooner or later.:eek:

[Fri3Oil System]

Well, I just said, companies are doing it... that's why We will have to study if it's a goo manner or not... they claim it's wonderful...

[NoNickName]

This is the first time I read that nitrogen kills. Building up 74% of our atmosphere, we would all be dead by now.
Take a full blow of nitrogen, and the worst that can happen is you getting paler and your heart beating faster for moving more oxygen around your body. It take more than a minute in pure nitrogen atmosphere for fainting.
Nitrogen blow, again, is the old legacy, inherited and all in all obsolete way of brazing. These days, gas fluxing is the way to go. There are liquid boron compounds to be mixed with torch gas that are much more effective in reducing the black spots around brazings, and don't need you to take heavy bottles of liquid nitrogen around.
The best of all is Fri3oil above, who flushes with R22: hope your kids don't grow with three legs or retarded...

[Fri3Oil System]

The best of all is Fri3oil above, who flushes with R22: hope your kids don't grow with three legs or retarded...

I must repeat I don't do that, but some of my clients. When I have children, I'll send you some pics... if they look like their mum, they'll be lovely as well. :)

Regards,

Nando.

[Peter_1]

...
Nitrogen blow, again, is the old legacy, inherited and all in all obsolete way of brazing. These days, gas fluxing is the way to go. There are liquid boron compounds to be mixed with torch gas that are much more effective in reducing the black spots around brazings, and don't need you to take heavy bottles of liquid nitrogen around....

You can't prevent carbonizing inside the tube with adding or mixing gases to your solder flame. It's in the inside it harms the system the most.
Only flushing with a neutral gas - not necessarily OFN - while soldering will prevents this.

[NoNickName]

Believe it or not, gasflux protects the inside of the pipe even when brazing from the outside. It probably has got some penetration capability through the swage. It worked for me so far.

[Tycho]

Useful vid:

http://www.youtube.com/watch?v=3uP-eb8Zz08 (http://bluesplayer.co.uk/youtube_wow/video/3uP-eb8Zz08/Brazing-with-Nitrogen-vs-Brazing-without-Nitrogen.html)

THIS!

Brazing without purging the pipe with N2 or any inert gas is just wrong

[Tycho]

Hi,

In Spain, many companies now are welding without N2, and then, they flush with any gas, (R22 for instance) and eliminate all the debris and carbon.

It looks the results are quite good... maybe we'll have to make another video.

regards,

Nando.

well that's against the law :)

[Tycho]

This is the first time I read that nitrogen kills. Building up 74% of our atmosphere, we would all be dead by now.
Take a full blow of nitrogen, and the worst that can happen is you getting paler and your heart beating faster for moving more oxygen around your body. It take more than a minute in pure nitrogen atmosphere for fainting.
Nitrogen blow, again, is the old legacy, inherited and all in all obsolete way of brazing. These days, gas fluxing is the way to go. There are liquid boron compounds to be mixed with torch gas that are much more effective in reducing the black spots around brazings, and don't need you to take heavy bottles of liquid nitrogen around.
The best of all is Fri3oil above, who flushes with R22: hope your kids don't grow with three legs or retarded...

Sorry mate, I don't care what you say or do, but no matter what gas you use, or what you mix in to the gas stream when you are brazing, it will not penetrate the overlaps on the copper pipes/fittings in any amount large enough to prevent the pipes from forming oxidation on the inside.

and reducing black spots around brazings sure, but what about the inside of the pipe?

[Tycho]

Believe it or not, gasflux protects the inside of the pipe even when brazing from the outside. It probably has got some penetration capability through the swage. It worked for me so far.

I'd like to see that, seriously.

can you send me the name of what you are using, and who supplies it?


if it works, I won't have to lug around the N2 bottle

[NoNickName]

http://www.gasflux.com/liquid.htm

[djbe]

Believe it or not, gasflux protects the inside of the pipe even when brazing from the outside. It probably has got some penetration capability through the swage. It worked for me so far.

HOW??

"It probably" is hardly precise.

Have looked at their website and it is not clear.

Until someone could provide me with photographic and scientific evidence that it works I think I will stick with Nitrogen thanks.

[raz5]

Using OFN for brazing and welding is all i know and will stick with it, leak testing the same but helium has its rewards :D

[Tycho]

http://www.gasflux.com/liquid.htm

No way that is going to eliminate oxidation on the inside of the pipe.

Working as a flux from the outside to make the silver/copper additive flow, and make the outside look better, sure, but preventing oxidation on the inside, nuhu, naha, not gonna happen.


I thought it might be a powder that you dipped the end of the pipes in, and that it would create a gas when it got heated up, so it would "purge" the oxygen from the within the pipe.

But a sole additive to the gas is'nt going to prevent oxidation inside the pipe

[NoNickName]

Don't know. Works for me and that's all. Stick with OFN if you're happy with it.

[chemi-cool]

Any inert gas will do the job, OFN is the cheapest choice.

When I weld SS coils, Argon is used.

[james10]

[quote=NoNickName;196412]This is the first time I read that nitrogen kills. Building up 74% of our atmosphere, we would all be dead by now.
A few links to read, many people are unaware of the dangers of nitrogen when in fact it is deadly,
http://en.wikipedia.org/wiki/Nitrogen_asphyxiation
http://www.csb.gov/assets/document/SB-Nitrogen-6-11-03.pdf
http://industrialplantsafety.com/dangers-of-nitrogen.html

[NoNickName]

Again, nitrogen is not deadly, as helium is not deadly, but oxygen is necessary for breathing. One does not need any licence or authorisation to handle nitrogen.
CO2 is toxic, nitrogen isn't.

[james10]

Again, nitrogen is not deadly, as helium is not deadly, but oxygen is necessary for breathing. One does not need any licence or authorisation to handle nitrogen.
CO2 is toxic, nitrogen isn't.
Question. if you took your gauge line and took a long deep breath of OFN what would happen.
Answer, You would drop dead on the spot.
Concluding that OFN is in fact deadly not toxic correct but is a suffocating gas and cannot be breathed,and causes over 8 deaths a year in the US alone

[NoNickName]

Question. if you took your gauge line and took a long deep breath of OFN what would happen.
Answer, You would drop dead on the spot.


No, you don't. Stop talking nonsense.

If you breathe nitrogen, you would in theory get 20 seconds after your lungs were pretty much deoxygenated (ie, down to 30% of normal oxygen content). BUT it takes some breaths to do that, since your functional residual lung capacity (what's in your lungs at the end of a normal expiration) is 4 or 5 times your "tidal volume" (what you breathe in a normal breath). So if you take your oxygen level down (say) 20% with each breath, your oxygen is (0.8)^5 = .32 = 32% of normal after 5 breaths, so at 5 seconds a breath it takes 25 seconds to get you functionally to the top of Everest or a ****pit at 28,000 ft. Add a few more seconds for ciculation time to the head, and 40 seconds total is a fair estimate for how long to pass out. Faster, of course, if you huff and puff.

http://yarchive.net/med/breathing_nitrogen.html
Newsgroups: sci.chem,sci.med Subject: Re: Nitrogen KILLS Date: 7 Oct 2004 11:00:48 -0700 Message-ID: <79cf0a8.0410071000.75787115@posting.google.com (http://groups.google.com/groups/search?as_umsgid=79cf0a8.0410071000.75787115%40posting.google.com)>

[NoNickName]

and c o c k pit is a perfectly legitimate word.

[Peter_1]

If inhalating helium should be deadly, then my kids and I should be death already a long time and many times when we did this when we wanted to speak like Donald Duck. You just becomes a little bit dizzy, that's all.

[Tycho]

Again, nitrogen is not deadly, as helium is not deadly, but oxygen is necessary for breathing. One does not need any licence or authorisation to handle nitrogen.
CO2 is toxic, nitrogen isn't.

Here's an experiment I suggest you don't try: go into a small walk in cooler, bring with you a hose connected to a bottle of OFN, close the door, have someone on the outside open the valve on said bottle... now stay in that room for an hour...

after an hour in there, leave the room, oh wait, you can't because you are dead...

why are you dead? because the Nitrogen displaced all the oxygen in the room, that's why...

[Tycho]

If inhalating helium should be deadly, then my kids and I should be death already a long time and many times when we did this when we wanted to speak like Donald Duck. You just becomes a little bit dizzy, that's all.

you know why you become dizzy now do you? right, right?

obviously you dont...

You get dizzy from asphyxia, your body is not getting the amount of oxygen you need, because you are breathing in large amounts of gas that the body cant use....


***** gas could be used to inflate balloons as well, they would drop to the ground tho, you could breath that gas in to alter your voice as well, it would get deeper, since it's a gas heavier than air... and you would get dizzy, because it displaces oxygen, and it is heavier than air, so it would be harder to get out of your lungs, and.


I watched a show on TV 10-15 years ago where a ref guy used ***** to inflate an air mattress, the air mattress was in a tent, and he almost lost two of his kids because the mattress was leaking.


Don't be stupid and inhale things people are not supposed to inhale

[Koopy]

when welding in R410A systems it is even more improtant as when the oil and refrigerant mix they form an abrasive, so with the velocity of the refrigerant pumping through your pipes it polishes the insides of your pipe work.
So if any carbonisation is present, you will pump this through the system to be caught up in all your components.

Can only equal disasters.

Good practice is to always use nitro!

[Peter_1]

you know why you become dizzy now do you? right, right?

obviously you dont...

...
Yes I did Tycho - this is in fact one of the courses I give for PPL where I explain how the body reacts with changing heights and pressures and the phenomenas associating with this - but the point is that we replied to a post of James10 where he said that you will be dead with one (!!!) inhalation of OFN and this isn't true.
You're speaking of a whole room filled with OFN and you stay in there for an hour. That's an apple/pear comparison you're making now.

[NoNickName]

FWIW, a room filled with anything else that air would cause me to die sooner or later.

[Peter_1]

Even with pure oxygen ;)

[monkey spanners]

Even with pure oxygen ;)

There was a guy i read about a few years ago, he was in an oxygen tent in hospital when he decided he needed a cigarette...

I guess thats one way to quit smoking :rolleyes:

[imran ansari]

well that's against the law :)
R-22 is harmful for ozone. How they recover after flushing with R-22?

[gazza666]

Can you use carbon dioxide for brazing?
If you can then hook up a pipe to someone’s mouth wile they blow down the pipe
Reduce the end of the pipe to produce a steady flow should be able to braze the joint if they are quick before you run out of breath LOL

[Makeit go Right]

Hard to do the braze with your mounth over the end of the pipe, though.

[Contactor]

No special flame or flux will prevent oxide formation.

Nitrogen is not toxic.

[Iceberg1138]

I've tried CO2; it effectively stops carbon from forming in the tubing. However, CO2 can contain water where nitrogen cannot. Everyone reading this should already know that moisture is an enemy to refrigeration. So unless you want to buy medical grade anhydrous CO2 (very expensive), don't use it. I found out the hard way on this one, it took two days and triple evacuation to correct the moisture I inadvertently introduced into a ten ton split A/C system with CO2. If it were cheaper, anhydrous CO2 would be ideal. The tanks are much smaller and lighter (if you get aluminum tanks) for the same cubic feet of gas, as it is a liquid in the tank and at a much lower pressure than a full nitrogen tank is.

[casstrig]

Nitrogen is used as it is an inert gas which means it does not react and copper when heated is reactive with oxygen.Also dry nitrogen is used for pressure testing but for brazing any inert gas will do such as co2.Nitrogen is not dangerous as long as there is sufficient air to breath so us in a well ventilated space.

[hvac01453]

We use nitrogen all the time but I must admit once in a while you get that fitting that just wont close, and you chase that one joint around for an hour using up all the nitro trying to get it to close. Ive found if you get your gauge down to barely leak out and go through your manifold gauges with the hose off and connect up ffor a few minutes till it flows out an open schraeder, youll be OK but sometimes through all this when Im done it either stopped flowing or the pressure is racing. I wish the had a special set of gauges that made adjustments down to 1 or 2 PSI,... If they're out there, I haven't seen them. Nitrogen isn't harmful... you breathe it all day long...CO2 I have used in a pinch because the bottle lasts 6 times longer than Nitrogen and has much higher pressure to blow out a condenser coil of dirt. The only downfall is the bottle frosts up and looses pressure after a while till it boils off inside the bottle from resting or a handy propane torch...Nitrogen is also dry so it helps dry the system. CO2 cools the pipe a bit and this MAY cause condensation inside the piping if it were cold enough...

[Contactor]

It's possible for Nitrogen to cool larger joints if the pressure is too high, it helps to braze on a bit of capillary at the other end to keep the flow down, all you need is 1 or 2 psi but that won't be enough if you have a long run in big pipe with the end open

[Fri3Oil System]

well that's against the law :)
Hi Tycho,

I might not explained myself clearly. R-22 is not released to the ambient, it "re-circulates" and brings all the debris out the circuit, but no R-22 is released. And that is quite legal :)

Regards,

Nando.