Brazing Stainless Steel...
Patrick, Mon Mar 18 2013, 07:09PM( this is an entirely different purpose from my "soldering of nickel" thread. )
Im having trouble getting good wetting and flow from my nickel-silver brazing rods to the Stainless.
iM wondering if the loss of true mapp gas is a contributing factor? I now only have the "Map // Pro" crap now.
Im using alot of flux, its the right knind of rod and flux (HAR-14FC-18), im getting it clean, tight fit-up and shiny, then red-yellow hot, the rod melts but they are slow to flow and cappillary into the joint.
should i use OXy-acetylene?
Is there any advise for my circumstance? Id be grateful.
Re: Brazing Stainless Steel...
Platinum, Mon Mar 18 2013, 10:02PM
Do you have a TIG set you could use, this would save alot of trouble, or even a MIG set with SS filler (308L is the best, as this welds most grades of SS)
You can weld SS with oxyacetylene with SS Filler rods used in TIG welding. If everyone is using the TIG sets at work, I use this method. With acceptable results. Make sure you use flux with this method. If I remember alot more acetylene is used, with a neutral flame.
Platinum, Mon Mar 18 2013, 10:02PM
Do you have a TIG set you could use, this would save alot of trouble, or even a MIG set with SS filler (308L is the best, as this welds most grades of SS)
You can weld SS with oxyacetylene with SS Filler rods used in TIG welding. If everyone is using the TIG sets at work, I use this method. With acceptable results. Make sure you use flux with this method. If I remember alot more acetylene is used, with a neutral flame.
Re: Brazing Stainless Steel...
Ash Small, Mon Mar 18 2013, 10:32PM
You could try using pure copper for brazing stainless. It's a long time since I've done it, but I seem to remember it can be much easier. I can't remember what flux I used, but google should turn something up. If not, just try using what you have, or whatever is easily available. (I know I used to use borax and/or boric acid on occasions). It's probably 20 years or more (at least) since I last tried it.
Ash Small, Mon Mar 18 2013, 10:32PM
You could try using pure copper for brazing stainless. It's a long time since I've done it, but I seem to remember it can be much easier. I can't remember what flux I used, but google should turn something up. If not, just try using what you have, or whatever is easily available. (I know I used to use borax and/or boric acid on occasions). It's probably 20 years or more (at least) since I last tried it.
Re: Brazing Stainless Steel...
Patrick, Mon Mar 18 2013, 11:31PM
im trying to avoid thermal distortion, but i guess TIG'ing could do less heating too.
Patrick, Mon Mar 18 2013, 11:31PM
im trying to avoid thermal distortion, but i guess TIG'ing could do less heating too.
Re: Brazing Stainless Steel...
Hazmatt_(The Underdog), Tue Mar 19 2013, 12:09AM
You will probably have to TIG it.
Oxy-Acetylene will cause the stainless to catch fire.
A big problem with torching stainless, and exposing it to an oxygen atmosphere, is that the Nickle content oxidizes, which you cannot solder to, and the Chromium diffuses, causing the metal to become brittle and crack. Get it too hot, and it will combust.
I was researching how to repair one of my stainless vacuum traps and found that oxidation is avoided by industry during welding/soldering by the use of an ammonia or intert gas atmosphere, and intense heating, but who has that capability in their backyard!
Most of us dont.
But if you TIG your workpiece, you should be okay.
Hazmatt_(The Underdog), Tue Mar 19 2013, 12:09AM
You will probably have to TIG it.
Oxy-Acetylene will cause the stainless to catch fire.
A big problem with torching stainless, and exposing it to an oxygen atmosphere, is that the Nickle content oxidizes, which you cannot solder to, and the Chromium diffuses, causing the metal to become brittle and crack. Get it too hot, and it will combust.
I was researching how to repair one of my stainless vacuum traps and found that oxidation is avoided by industry during welding/soldering by the use of an ammonia or intert gas atmosphere, and intense heating, but who has that capability in their backyard!
Most of us dont.
But if you TIG your workpiece, you should be okay.
Re: Brazing Stainless Steel...
doctor electrons, Tue Mar 19 2013, 12:47AM
Use a low temperature silver solder and the appropriate flux and you'll be fine. When in doubt, tig it!
doctor electrons, Tue Mar 19 2013, 12:47AM
Use a low temperature silver solder and the appropriate flux and you'll be fine. When in doubt, tig it!
Re: Brazing Stainless Steel...
Carl A. Willis, Tue Mar 19 2013, 06:27AM
Brazing of stainless steel with silver alloys is usually pretty straightforward. I do quite a bit of it.
Flux is important. It is sold in two varieties: "white" (suitable for small, delicate work) and "black" (suitable for heavy-duty jobs). Look for suitable flux by these names. It is inexpensive and probably available locally in a welding supply store. If not, eBay is a great source.
Temperature is important. You must be able to reach a uniform, cherry-red color or the braze alloy won't melt. MAPP gas is fine. Acetylene is fine. Propane is fine. (All are typically combined with oxygen in a premix blowpipe torch). A slightly reducing flame is recommended, but it doesn't matter too much as long as you don't overheat the metal.
Cleanup is important. First, get the hardened flux off the finished joint by dropping the still-hot part into hot water. Pickling improves the surface appearance and restores the protective "stainless" properties to the alloy. To pickle 304 stainless after brazing or welding, obtain some Whink (hydrofluoric acid) from WalMart or other business with a well-stocked cleaning aisle, and some 70% nitric acid (can usually be obtained by the gallon jug from a metal plating shop; expect to pay about $50 cash for the privilege). Mix the Whink, the nitric acid, and some warm tap water in about a 1:1:1 ratio and drop the part in it. Lift it out every few minutes to wipe off the surfaces with a sponge (black junk often comes loose). Be sure to wear gloves. Dilute HF is not a problem usually, but in the presence of dilute nitric acid it becomes much more corrosive to tissues and it causes very annoying delayed burns under the fingernails. Parts are usually suitably pickled in under a couple hours and come out looking great. The pickling solution can be stored and reused.
-Carl
Carl A. Willis, Tue Mar 19 2013, 06:27AM
Brazing of stainless steel with silver alloys is usually pretty straightforward. I do quite a bit of it.
Flux is important. It is sold in two varieties: "white" (suitable for small, delicate work) and "black" (suitable for heavy-duty jobs). Look for suitable flux by these names. It is inexpensive and probably available locally in a welding supply store. If not, eBay is a great source.
Temperature is important. You must be able to reach a uniform, cherry-red color or the braze alloy won't melt. MAPP gas is fine. Acetylene is fine. Propane is fine. (All are typically combined with oxygen in a premix blowpipe torch). A slightly reducing flame is recommended, but it doesn't matter too much as long as you don't overheat the metal.
Cleanup is important. First, get the hardened flux off the finished joint by dropping the still-hot part into hot water. Pickling improves the surface appearance and restores the protective "stainless" properties to the alloy. To pickle 304 stainless after brazing or welding, obtain some Whink (hydrofluoric acid) from WalMart or other business with a well-stocked cleaning aisle, and some 70% nitric acid (can usually be obtained by the gallon jug from a metal plating shop; expect to pay about $50 cash for the privilege). Mix the Whink, the nitric acid, and some warm tap water in about a 1:1:1 ratio and drop the part in it. Lift it out every few minutes to wipe off the surfaces with a sponge (black junk often comes loose). Be sure to wear gloves. Dilute HF is not a problem usually, but in the presence of dilute nitric acid it becomes much more corrosive to tissues and it causes very annoying delayed burns under the fingernails. Parts are usually suitably pickled in under a couple hours and come out looking great. The pickling solution can be stored and reused.
-Carl
Re: Brazing Stainless Steel...
Ash Small, Tue Mar 19 2013, 09:47AM
Here's an example of stainless steel refrigeration equipment brazed using copper:
Ash Small, Tue Mar 19 2013, 09:47AM
Here's an example of stainless steel refrigeration equipment brazed using copper:
Re: Brazing Stainless Steel...
Hazmatt_(The Underdog), Tue Mar 19 2013, 07:23PM
I'd always recommend staying away from even dilute HF. It really is nasty stuff, and can cost you your fingers, or worse.
Carl, if you have been burned by HF, you should talk to a physician. HF targets the Calcium in your bones and causes irreversible damage over time.
Something to think about.
Hazmatt_(The Underdog), Tue Mar 19 2013, 07:23PM
I'd always recommend staying away from even dilute HF. It really is nasty stuff, and can cost you your fingers, or worse.
Carl, if you have been burned by HF, you should talk to a physician. HF targets the Calcium in your bones and causes irreversible damage over time.
Something to think about.
Re: Brazing Stainless Steel...
Carl A. Willis, Tue Mar 19 2013, 09:23PM
Sure, abstinence is the only 100% effective protection. However: poisonous, corrosive fluorides are practically unavoidable if you get into brazing. They are in the flux (the name of the element itself attests to this use). They are in the pickle bath. They are hazardous materials and a wealth of relevant MSDSs are available online to deliver the canonical safety admonitions about handling them. It goes without saying that this information--whether for Whink, or flux, or whatever--should be the reference of first recourse for anyone unfamiliar with the products. If these kinds of warnings are one's only frame of reference, however, it is easy to conjure up scary scenarios that have little grounding in reality because the nuances are not discussed. HF at the ~2-3M concentration found in Whink, and recommended for use removing rust stains from clothing, is practically edible (used to taste like lemon juice, but they have put a bitterant in it now), whereas 40% reagent HF (which is not easy to obtain) will flay a man, eat his bones, AND ruin the glaze on his bathroom sink before he can say "calcium gluconate injection". I don't always wear gloves when I use Whink, but when I do, it's because there is nitric acid added to that Whink, giving it an appetite for live cuticle. And you know, come to think of it, goggles might not be a bad idea either! Safety first!
-Carl
Carl A. Willis, Tue Mar 19 2013, 09:23PM
Hazmatt_(The Underdog) wrote ...
I'd always recommend staying away from even dilute HF. It really is nasty stuff, and can cost you your fingers, or worse.
I'd always recommend staying away from even dilute HF. It really is nasty stuff, and can cost you your fingers, or worse.
Sure, abstinence is the only 100% effective protection. However: poisonous, corrosive fluorides are practically unavoidable if you get into brazing. They are in the flux (the name of the element itself attests to this use). They are in the pickle bath. They are hazardous materials and a wealth of relevant MSDSs are available online to deliver the canonical safety admonitions about handling them. It goes without saying that this information--whether for Whink, or flux, or whatever--should be the reference of first recourse for anyone unfamiliar with the products. If these kinds of warnings are one's only frame of reference, however, it is easy to conjure up scary scenarios that have little grounding in reality because the nuances are not discussed. HF at the ~2-3M concentration found in Whink, and recommended for use removing rust stains from clothing, is practically edible (used to taste like lemon juice, but they have put a bitterant in it now), whereas 40% reagent HF (which is not easy to obtain) will flay a man, eat his bones, AND ruin the glaze on his bathroom sink before he can say "calcium gluconate injection". I don't always wear gloves when I use Whink, but when I do, it's because there is nitric acid added to that Whink, giving it an appetite for live cuticle. And you know, come to think of it, goggles might not be a bad idea either! Safety first!
-Carl
Re: Brazing Stainless Steel...
Hazmatt_(The Underdog), Wed Mar 20 2013, 01:43AM
Carl,
I work with, on occasion, a One-Eyed Electroplater, who has been handling everything under the Sun for more than 60 years. He was careless, like not using rubber gloves rated for HF, which is important by the way.
I work with chemicals a lot as well, as I am an avid Inorganic Chemistry fan, take what you will from what I say, or Ignore it completely, I was just trying to say that I think you're being careless and might want to consider the risks you're taking, and that you might be causing harm to yourself and don't realize it.
We're not indestructable, accidents happen, but remember "An ounce of prevention, is worth a pound of cure."
Hazmatt_(The Underdog), Wed Mar 20 2013, 01:43AM
Carl,
I work with, on occasion, a One-Eyed Electroplater, who has been handling everything under the Sun for more than 60 years. He was careless, like not using rubber gloves rated for HF, which is important by the way.
I work with chemicals a lot as well, as I am an avid Inorganic Chemistry fan, take what you will from what I say, or Ignore it completely, I was just trying to say that I think you're being careless and might want to consider the risks you're taking, and that you might be causing harm to yourself and don't realize it.
We're not indestructable, accidents happen, but remember "An ounce of prevention, is worth a pound of cure."
Re: Brazing Stainless Steel...
Carl A. Willis, Wed Mar 20 2013, 06:03AM
So kind of you to draw attention to my carelessness (and remind other readers that you're looking out for me). Ah, if only my close friends and neighbors and my dear mother were so attuned to the situational risk decisions in my life, I might never need to think for myself. Shoot, if my tastes in safety were really downmarket, I could even crowdsource the ol' judgment thing to people online whose names or backgrounds I didn't even know, and get them to do it for free. La vie facile!
Earlier in this thread I dispensed some gratuitous safety advice myself (about wearing gloves now and then, and maybe even goggles, blah blah blah). I offer analogous platitudes more frequently in the context of someone getting ready to leave my place, when I will tell that person to "Drive Safely." I mean it, I really do! Nothing kills like road hazards. And yet for some reason nobody pays much heed to my admonition: they peel out of there like nothing had just been said about safety. I wonder why that is. I'm shocked to see those people return alive, again and again. You'd almost think that something besides my smarmy expression of concern for life and vehicle was responsible for keeping them alive. Maybe Jesus.
-Carl
Carl A. Willis, Wed Mar 20 2013, 06:03AM
So kind of you to draw attention to my carelessness (and remind other readers that you're looking out for me). Ah, if only my close friends and neighbors and my dear mother were so attuned to the situational risk decisions in my life, I might never need to think for myself. Shoot, if my tastes in safety were really downmarket, I could even crowdsource the ol' judgment thing to people online whose names or backgrounds I didn't even know, and get them to do it for free. La vie facile!
Earlier in this thread I dispensed some gratuitous safety advice myself (about wearing gloves now and then, and maybe even goggles, blah blah blah). I offer analogous platitudes more frequently in the context of someone getting ready to leave my place, when I will tell that person to "Drive Safely." I mean it, I really do! Nothing kills like road hazards. And yet for some reason nobody pays much heed to my admonition: they peel out of there like nothing had just been said about safety. I wonder why that is. I'm shocked to see those people return alive, again and again. You'd almost think that something besides my smarmy expression of concern for life and vehicle was responsible for keeping them alive. Maybe Jesus.
-Carl
Re: Brazing Stainless Steel...
klugesmith, Wed Mar 20 2013, 07:07AM
Continuing our drift away from the thread topic,
I respectfully think that conservative safety admonitions do belong here. Many readers are young and smart, and (like most teens) think they are indestructible.
Better to point out risks that would never occur to them. And occasionally offer firsthand examples of life-changing injuries or very close calls, just from bad luck during some ill-advised procedure that is harmless 99% of the time.
On the other hand, dumbing things down too much is like crying wolf.
Old timers who know and understand the risks should be careful not to project a cavalier attitude toward safety. A noob might repeat the experiment with an apparently inocuous change, that turns something truly safe into something with 1% chance of biting really hard, or creating a latent injury. "Proud Mary" thinks we are collectively too eager to help when kids want to make x-rays at home. Is it right to just say, "online forums are part of today's environment for Darwinian selection"?
One of my favorite examples is a website of one John DeArmond, "Neon John", whom some of our plasma globe makers might know, or be. Check out the picture at upper left of , which I have reproduced below.
That thing on the table is an energized magnetron from a MWO. Shall we cry out in horror? At lower left of the page, John states that it's a safe demo, that he knows what he's doing, and enjoys the hand-warming aspect (aka diathermy). I believe him, but need to repeat: "Professional driver on closed course. Do not try this at home."
klugesmith, Wed Mar 20 2013, 07:07AM
Continuing our drift away from the thread topic,
I respectfully think that conservative safety admonitions do belong here. Many readers are young and smart, and (like most teens) think they are indestructible.
Better to point out risks that would never occur to them. And occasionally offer firsthand examples of life-changing injuries or very close calls, just from bad luck during some ill-advised procedure that is harmless 99% of the time.
On the other hand, dumbing things down too much is like crying wolf.
Old timers who know and understand the risks should be careful not to project a cavalier attitude toward safety. A noob might repeat the experiment with an apparently inocuous change, that turns something truly safe into something with 1% chance of biting really hard, or creating a latent injury. "Proud Mary" thinks we are collectively too eager to help when kids want to make x-rays at home. Is it right to just say, "online forums are part of today's environment for Darwinian selection"?
One of my favorite examples is a website of one John DeArmond, "Neon John", whom some of our plasma globe makers might know, or be. Check out the picture at upper left of
, which I have reproduced below.
That thing on the table is an energized magnetron from a MWO. Shall we cry out in horror? At lower left of the page, John states that it's a safe demo, that he knows what he's doing, and enjoys the hand-warming aspect (aka diathermy). I believe him, but need to repeat: "Professional driver on closed course. Do not try this at home."
Re: Brazing Stainless Steel...
johnf, Wed Mar 20 2013, 08:12AM
Okay Guys
From 40 years experience in working with stainless
Hard solders should be avoided they will eventually let go --usually at the most inappropriate time.
The welds look good but a bit of thermal cycling will fracture the weld leaving a perfectly clean surface on one or the other surfaces --proof of non compatibility.
your options are
soft solder 60:40 is ok but you need a good acid flux -killed spirits of salts (ZnCl) works well with clean stainless. --do not over heat while using this otherwise you have to re-clean the SS.
Soft solder with added silver also good same flux as above but wash it very carefully after soldering.
do not use lead free solders these are worse than hard solders as far as joint strength stickability goes
Stick welding with 316L arc rods is good but you need a good welder to use 1.6mm arc rods --I have used these for UHV work.
MIG welding for heavier sections works well pays to use a bit of shielding gas on the inside to minimise oxidization.
Tig the preferred option this again needs a good welder capable of running down to 2-5 amps with HF start (especially good for very thin stuff like bellows) again use some of the shielding gas on the inside to minimise oxidisation.
If you cannot do any of these things wel,l two pot epoxy is good.
johnf, Wed Mar 20 2013, 08:12AM
Okay Guys
From 40 years experience in working with stainless
Hard solders should be avoided they will eventually let go --usually at the most inappropriate time.
The welds look good but a bit of thermal cycling will fracture the weld leaving a perfectly clean surface on one or the other surfaces --proof of non compatibility.
your options are
soft solder 60:40 is ok but you need a good acid flux -killed spirits of salts (ZnCl) works well with clean stainless. --do not over heat while using this otherwise you have to re-clean the SS.
Soft solder with added silver also good same flux as above but wash it very carefully after soldering.
do not use lead free solders these are worse than hard solders as far as joint strength stickability goes
Stick welding with 316L arc rods is good but you need a good welder to use 1.6mm arc rods --I have used these for UHV work.
MIG welding for heavier sections works well pays to use a bit of shielding gas on the inside to minimise oxidization.
Tig the preferred option this again needs a good welder capable of running down to 2-5 amps with HF start (especially good for very thin stuff like bellows) again use some of the shielding gas on the inside to minimise oxidisation.
If you cannot do any of these things wel,l two pot epoxy is good.
Re: Brazing Stainless Steel...
Ash Small, Wed Mar 20 2013, 10:29AM
I've found a paper here on brazing stainless steel using copper:
While, in this instance, a vacuum furnace is used, it is possible using other methods.
The paper goes into some detail regarding why using copper is the preffered method in critical applications. I'm surprised no-one else has come accross this method of joining stainless, and it's quite possibly not required in this instance, but using copper to braze stainless is the preffered option in critical applications.
Regarding the OT posts in this thread, if you don't know what you are doing with HF, a splash on your hand often results in amputation of the whole arm. Calcium glutonate injections (even if given immediately, and how many of us have a syringe of it on the bench?) doesn't always prevent amputation.
As far as I'm aware, the only substances resistant to HF are guttapercha (natural rubber) and polythene (polyethylene). I usually put polythene bags over my hands when using it, even when very dilute.
Ash Small, Wed Mar 20 2013, 10:29AM
I've found a paper here on brazing stainless steel using copper:
While, in this instance, a vacuum furnace is used, it is possible using other methods.
The paper goes into some detail regarding why using copper is the preffered method in critical applications. I'm surprised no-one else has come accross this method of joining stainless, and it's quite possibly not required in this instance, but using copper to braze stainless is the preffered option in critical applications.
Regarding the OT posts in this thread, if you don't know what you are doing with HF, a splash on your hand often results in amputation of the whole arm. Calcium glutonate injections (even if given immediately, and how many of us have a syringe of it on the bench?) doesn't always prevent amputation.
As far as I'm aware, the only substances resistant to HF are guttapercha (natural rubber) and polythene (polyethylene). I usually put polythene bags over my hands when using it, even when very dilute.
Re: Brazing Stainless Steel...
macona, Thu Mar 21 2013, 09:12AM
I am sorry, but this is utter BS. Stainless is silver brazed all the time. Done it many, many times at work and I have also worked in the welding industry (I was a Miller certified tech). I have never, ever heard of stainless combusting.
Ammonia as a purge gas? You have got to be kidding. We use anhydrous ammonia for refrigeration at work and you dont want to be anywhere near that stuff. You can back purge with any inert gas. The simplest thing to do is put a splitter on the argon line if you are tigging and run a line to the inside of the pipe you are welding.
The main thing is dont overheat your metal, thats when you can sugar the stainless, this happens with tig as well. The best way is to preflux your parts. Cut silver brazing strips and set the up along the joint. Heat the parts evenly and the metal will flow. The braze will follow the torch though the joint as you make a good bond.
Use oxy-acet or oxy-propane. Either will do fine. I like the white flux, some people use the black flux, it is better for stainless. Stainless is very easy to solder braze. The right tools will help. If you dont have an oxy-fuel setup look on craigslist. There are people selling them all the time. I have two, One with a medium size acet bottle and a 150cu ft O2 bottle and a little portlable set with a MC and a 20cuft O2 bottle.
Bit of acetylene trivia, the two smallest bottles are called MC and B bottles. MC being the smallest. The name came from what they were used on as a source of lighting, MC was used for motorcycles, B bottles were used on buses. This is the reason for the angled valve as well on the MC, they were intended to be run with the bottle at an incline.
macona, Thu Mar 21 2013, 09:12AM
Hazmatt_(The Underdog) wrote ...
You will probably have to TIG it.
Oxy-Acetylene will cause the stainless to catch fire.
A big problem with torching stainless, and exposing it to an oxygen atmosphere, is that the Nickle content oxidizes, which you cannot solder to, and the Chromium diffuses, causing the metal to become brittle and crack. Get it too hot, and it will combust.
I was researching how to repair one of my stainless vacuum traps and found that oxidation is avoided by industry during welding/soldering by the use of an ammonia or intert gas atmosphere, and intense heating, but who has that capability in their backyard!
Most of us dont.
But if you TIG your workpiece, you should be okay.
You will probably have to TIG it.
Oxy-Acetylene will cause the stainless to catch fire.
A big problem with torching stainless, and exposing it to an oxygen atmosphere, is that the Nickle content oxidizes, which you cannot solder to, and the Chromium diffuses, causing the metal to become brittle and crack. Get it too hot, and it will combust.
I was researching how to repair one of my stainless vacuum traps and found that oxidation is avoided by industry during welding/soldering by the use of an ammonia or intert gas atmosphere, and intense heating, but who has that capability in their backyard!
Most of us dont.
But if you TIG your workpiece, you should be okay.
I am sorry, but this is utter BS. Stainless is silver brazed all the time. Done it many, many times at work and I have also worked in the welding industry (I was a Miller certified tech). I have never, ever heard of stainless combusting.
Ammonia as a purge gas? You have got to be kidding. We use anhydrous ammonia for refrigeration at work and you dont want to be anywhere near that stuff. You can back purge with any inert gas. The simplest thing to do is put a splitter on the argon line if you are tigging and run a line to the inside of the pipe you are welding.
The main thing is dont overheat your metal, thats when you can sugar the stainless, this happens with tig as well. The best way is to preflux your parts. Cut silver brazing strips and set the up along the joint. Heat the parts evenly and the metal will flow. The braze will follow the torch though the joint as you make a good bond.
Use oxy-acet or oxy-propane. Either will do fine. I like the white flux, some people use the black flux, it is better for stainless. Stainless is very easy to solder braze. The right tools will help. If you dont have an oxy-fuel setup look on craigslist. There are people selling them all the time. I have two, One with a medium size acet bottle and a 150cu ft O2 bottle and a little portlable set with a MC and a 20cuft O2 bottle.
Bit of acetylene trivia, the two smallest bottles are called MC and B bottles. MC being the smallest. The name came from what they were used on as a source of lighting, MC was used for motorcycles, B bottles were used on buses. This is the reason for the angled valve as well on the MC, they were intended to be run with the bottle at an incline.
Re: Brazing Stainless Steel...
Hazmatt_(The Underdog), Fri Mar 22 2013, 01:16AM
I wanted to see if my stainless steel mesh "Chicken Wire" could be brazed, its 304 stainless, and as I used Oxy-propane, it burst into flames, much like overheating a Cerium "flint" striker. So yea, it can ignite, try it for yourself.
The Ammonia gas atmosphere is used on high production intense heating oven assembly lines as a purge gas. Not sure how they managed, but when I was looking at a company profile, that's what they said they did for their process. If that's not true, then that's fine, it's the way they did things.
And they could have chosen any gas I guess, its what they used.
I've also used the white Sodium Flouride flux and silver bearing solder to try to fix my SS condensation trap, and it was garbage.
Bought it from Cameron welding supply, brand new, never worked. As soon as it got hot, the Boric Acid in the mix became all gummy and prevented brazing.
Phosphoric Acid worked for me, with 60/40.
Hazmatt_(The Underdog), Fri Mar 22 2013, 01:16AM
I wanted to see if my stainless steel mesh "Chicken Wire" could be brazed, its 304 stainless, and as I used Oxy-propane, it burst into flames, much like overheating a Cerium "flint" striker. So yea, it can ignite, try it for yourself.
The Ammonia gas atmosphere is used on high production intense heating oven assembly lines as a purge gas. Not sure how they managed, but when I was looking at a company profile, that's what they said they did for their process. If that's not true, then that's fine, it's the way they did things.
And they could have chosen any gas I guess, its what they used.
I've also used the white Sodium Flouride flux and silver bearing solder to try to fix my SS condensation trap, and it was garbage.
Bought it from Cameron welding supply, brand new, never worked. As soon as it got hot, the Boric Acid in the mix became all gummy and prevented brazing.
Phosphoric Acid worked for me, with 60/40.
Re: Brazing Stainless Steel...
Ash Small, Fri Mar 22 2013, 04:09PM
Boric acid does require hotter temperatures, but it does clean very well, due to it being more aggressive (and gets thicker as it does it's job).
I used to use a borax/boric acid mix, and just keep adding more borax as it thickened, or wiped it off and added more boric acid, but at the time I had a 50 kilo sack of each, and I used to use a carbon arc flame. Boric acid, once it's full of oxides, etc. does tend to come off as flying glass as the workpiece cools, though.
I think, when I was brazing copper to stainless, it was so that I could then solder to the copper, I do remember that it was surprisingly easy to get the copper to flow and stick, though.
Ash Small, Fri Mar 22 2013, 04:09PM
Hazmatt_(The Underdog) wrote ...
I wanted to see if my stainless steel mesh "Chicken Wire" could be brazed, its 304 stainless, and as I used Oxy-propane, it burst into flames, much like overheating a Cerium "flint" striker. So yea, it can ignite, try it for yourself.
The Ammonia gas atmosphere is used on high production intense heating oven assembly lines as a purge gas. Not sure how they managed, but when I was looking at a company profile, that's what they said they did for their process. If that's not true, then that's fine, it's the way they did things.
And they could have chosen any gas I guess, its what they used.
I've also used the white Sodium Flouride flux and silver bearing solder to try to fix my SS condensation trap, and it was garbage.
Bought it from Cameron welding supply, brand new, never worked. As soon as it got hot, the Boric Acid in the mix became all gummy and prevented brazing.
Phosphoric Acid worked for me, with 60/40.
I wanted to see if my stainless steel mesh "Chicken Wire" could be brazed, its 304 stainless, and as I used Oxy-propane, it burst into flames, much like overheating a Cerium "flint" striker. So yea, it can ignite, try it for yourself.
The Ammonia gas atmosphere is used on high production intense heating oven assembly lines as a purge gas. Not sure how they managed, but when I was looking at a company profile, that's what they said they did for their process. If that's not true, then that's fine, it's the way they did things.
And they could have chosen any gas I guess, its what they used.
I've also used the white Sodium Flouride flux and silver bearing solder to try to fix my SS condensation trap, and it was garbage.
Bought it from Cameron welding supply, brand new, never worked. As soon as it got hot, the Boric Acid in the mix became all gummy and prevented brazing.
Phosphoric Acid worked for me, with 60/40.
Boric acid does require hotter temperatures, but it does clean very well, due to it being more aggressive (and gets thicker as it does it's job).
I used to use a borax/boric acid mix, and just keep adding more borax as it thickened, or wiped it off and added more boric acid, but at the time I had a 50 kilo sack of each, and I used to use a carbon arc flame. Boric acid, once it's full of oxides, etc. does tend to come off as flying glass as the workpiece cools, though.
I think, when I was brazing copper to stainless, it was so that I could then solder to the copper, I do remember that it was surprisingly easy to get the copper to flow and stick, though.
Re: Brazing Stainless Steel...
macona, Sun Mar 24 2013, 11:28PM
Just about any metal will burn at high temps when it is chicken wire size. It will overshoot brazing temperature quickly and start vaporizing unless you are very careful.
Ammonia might be used in something like a massive welding furnace. To fill something like that with argon would cost a small fortune. It is also possible they are going for a specific reaction with the metal since ammonia is definitely reactive.
macona, Sun Mar 24 2013, 11:28PM
Hazmatt_(The Underdog) wrote ...
I wanted to see if my stainless steel mesh "Chicken Wire" could be brazed, its 304 stainless, and as I used Oxy-propane, it burst into flames, much like overheating a Cerium "flint" striker. So yea, it can ignite, try it for yourself.
The Ammonia gas atmosphere is used on high production intense heating oven assembly lines as a purge gas. Not sure how they managed, but when I was looking at a company profile, that's what they said they did for their process. If that's not true, then that's fine, it's the way they did things.
And they could have chosen any gas I guess, its what they used.
I wanted to see if my stainless steel mesh "Chicken Wire" could be brazed, its 304 stainless, and as I used Oxy-propane, it burst into flames, much like overheating a Cerium "flint" striker. So yea, it can ignite, try it for yourself.
The Ammonia gas atmosphere is used on high production intense heating oven assembly lines as a purge gas. Not sure how they managed, but when I was looking at a company profile, that's what they said they did for their process. If that's not true, then that's fine, it's the way they did things.
And they could have chosen any gas I guess, its what they used.
Just about any metal will burn at high temps when it is chicken wire size. It will overshoot brazing temperature quickly and start vaporizing unless you are very careful.
Ammonia might be used in something like a massive welding furnace. To fill something like that with argon would cost a small fortune. It is also possible they are going for a specific reaction with the metal since ammonia is definitely reactive.
Re: Brazing Stainless Steel...
Ash Small, Mon Mar 25 2013, 12:26PM
Ammonia can be used in some heat treating of steels, ie nitriding.
Ash Small, Mon Mar 25 2013, 12:26PM
Ammonia can be used in some heat treating of steels, ie nitriding.
Re: Brazing Stainless Steel...
Patrick, Sat Apr 06 2013, 04:14PM
im using mild, low carbon, and common steel, brazed with alloy bolts (80k psi), brazed with the bronze, which is super easy.
ill continue to try with nickel-silver, on SS, but MAPP pro just seems to weak to get good flow on a part with more than 1 inch surface area.
Patrick, Sat Apr 06 2013, 04:14PM
im using mild, low carbon, and common steel, brazed with alloy bolts (80k psi), brazed with the bronze, which is super easy.
ill continue to try with nickel-silver, on SS, but MAPP pro just seems to weak to get good flow on a part with more than 1 inch surface area.
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