Just had something that was bugging me with all these newbie welding stuff and MIG welding and that sort of thing.

It's not a big thing, but it is just like a small irritation beneath my skin.

I am a big fan of Oxy-Acetelyne welding and took some night classes. Not just 'artistic' welding, but real ones that were meant for people who were aiming for professional welding and that sort of thing. (this is a very good thing and not that expensive. Very useful stuff to learn). The reason I like it because it's just so useful for all sorts of different things. I can weld, I can heat bends, I can cut holes, I can cut metal. All sorts of fun stuff. Vaporizing a line through a 1/4 inch plate steel then cleaning up with a hand file is cheap and very quick and beats trying to do it with a hack saw.

Now I see people running around with Mig welders left and right and I absolutely understand the attractiveness of it. It's cheap, it's relatively easy, and very fast way to weld steel. I am not knocking it one bit. It's great stuff.

But one thing I think that people are missing is something called 'Bronze Welding' and also called 'Braze Welding' or 'Brazing' by a lot of welders.

Now it's not really accurate to call it 'brazing'. It's fine and is what a lot of people call it, but bronze welding and brazing are two different things. Related, but different.

With Gas techniques you have a great deal of flexibility. The flame allows a lot of temperature control and you can actually pretty easily gauge the temp of the gas flame by simply looking at it. It's kinda difficult to describe, but any decent welding book will have pictures that explain it. It's kinda cool.

So there are a few different 'joining techniques':

From colder/weaker to hotter/stronger

1. Soldering. Using lead/tin or some other mixture of stuff that melts at a low temperature. This works by having the soft metal flow into the joints and crevices of the different materials and, when it cools, it bonds them together like glue.

Soldering happens at temperatures less then 400 °C (752 °F).

2. Brazing. Very similar to soldering, but the difference is that it happens at over 450 °C. It can be done with copper alloys, gold, nickel alloy and other things of that nature. The basic idea is that your using flux and liquifed metal with heated surface metal to 'suck' the filler material in between the joints of metal through capillary action (or 'wicking' or whatever).

Now brazing can be surprisingly strong, but the key of making good joints is to have very clean material and very tight tolerances in fitting metal. Not too tight to restrict flowing, but pretty damn tight to. Like 0.003 inches tight for best strength. The metal flows in, rapidly cools, and locks the two pieces of base metal together. The looser the joint and the strength kinda falls off fairly rapidly, which may or may not be a bad thing depending on what you are wanting to do it with it. Still much stronger then soldering, typically.


3. Braze Welding. This happens at over 850 °C.

This is different. The major difference between this and brazing is that it is twice as hot and your actually doing welding of a sort. What happens is that your heating the base material up to a dull red glow. Not to the melting point, but still pretty hot. Then you start adding your bronze alloy.

This does _NOT_ depend on capillary action like regular brazing does. What is happening is that the bronze is flowing and mixing with the surface of the base metal to create a new alloy. So there is really no very abrupt stop from were the steel ends and the bronze starts... instead there is some small amount of surface mixing going on there. The nice thing that since it does not depend on capillary action then you joints do not have to be nearly as exact when compared to regular brazing. So it's much quicker process.

Then that steel-to-bronze-alloy-to-bronze-to-bronze-alloy-to-steel is a fairly solid hunk of metal that joins the two objects that need some of that 'oneness'.


4. Gas Welding. Happens at over 1600 °C for mild steel.

This is what is traditionally thought of as welding and is the art/science of taking two pieces of steel and make them one piece of steel. Ideally when you do your job right you can take something like a butt weld, cut it through the center and not be able to tell exactly were the joint is at... because there is no joint any more. One of the nice things about Oxy-Acel welding (and one of the bad things) is that it heats up the surrounding metal so hot that the crystal structure of the metal flows into one another making one of the strongest types of joints possible. Of course this has the tendency to distort everything to hell, so it's not really the most popular thing to do anymore. :)


NOW HERE IS THE KICKER:

Bronze has a high tensile strength.

To understand why you have to know a bit of metalurgy: The reason we use steel for everything is not because it's super-strong (it is), but because it is relatively LIGHT WEIGHT for it's strength (and price). But it's not necessarily the strongest.


(side note:)
It's like the debate between DOM tubing vs. EWR tubing vs. Chromoly vs. Poop Pipe.

It is probably possible to make a Poop Pipe roll cage for a truck that is every bit as strong as a Chrome-Moly tubing... it's just that it would be massive, stupid and expensive. It's just that the poop pipe would be so heavy that nobody would be able to have a competitive truck using it.

So that also why you'd use DOM tubing over EWR for a roll cage... not so much because just because DOM is stronger, but because DOM will be much lighter and cheaper for the same tensile strength as if you used EWR. Right? To reach the same target strength with EWR would require bigger and heavier tubes then if you used DOM tubing.

But DOM is much cheaper then Chromoly so it's worth using DOM for the majority of applications. The trade-off is not really strength per $$... the trade off is _weight_. You have to use bigger/thicker DOM tubes to reach the same strength. If you do your not losing anything in safety by using DOM, your losing out on _performance_ as your DOM-using truck will weigh more.

That is, of course, if you do your design correctly.
(end side note)


Ok.....

Now back to Braze Welding. Braze welding kicks-ass because the tensile strength of the joint is very high. With braze welding on mild steel the joint is will actually have a higher strength then the steel if you can believe that.


Here is the comparison:

Mild Steel (something like 1018-1020 used in EWR) has a ultimate tensile strength of about 60,000 to 80,000 psi.

Brazing, the ~450 °C process with capillary action, has a tensile strength of about 40,000 to 60,000 psi if you do a good job on the joint.

Braze Welding has a tensile strength of 50,000 to 70,000 psi! :laughing:

Brazing and Braze Welding has been used in racing car chassis building for decades. Of course with TIG and more exotic materials it's largely been displaced. But for poorer and lesser skilled people Braze still kicks ass.

And you don't need oxy-acetylene to do this either!

Even though I never have used one you can pick up a Propane/Mapp-Air torch kit for less then a hundred dollars and you can get Mapp or Propane gas at most hardware stores. This should get you hot enough to do brazing properly.

For braze welding you can probably pick up a oxy-mapp kit for not much more. And you can cut metal with that combination, also. Maybe something like this:
[(edit: *deleted* link)

Although do keep in mind that I have no experience with Mapp or propane torches. Just Oxy-Acetylene.


Sooooo.....


Advantages to Braze Welding:

* Cheaper -- uses less gas then welding and you can probably get by with cheaper rig.

* Faster -- less prep then brazing or gas welding. You don't need to heat the metal up to melting point to join them. (You still need to have pretty clean metal to work with, of course. So don't expect it to 'cut' through crusty stuff like you can with electric welding.) The metal does not oxidize that fast so there is little scale to clean up and that sort of thing. Smoother, too.

* Easier -- there is very little chance you'll burn through the metal. If your slow you'll probably distort thin metal and cause problems (metal that starts to melt won't braze properly.. it causes the bronze filler rod to splatter and spit). But it's pretty simple to get a decent joint. It's kinda easy to do a visual inspection.

* Works with cast iron -- It's very difficult to properly weld cast iron. However braze welding works with cast iron very well. So much so that it can be used for repairing things like broken bits off of engine blocks or fixing exhaust manifolds (with proper cleaning).

I suppose it's like a ghetto-TIG welding. Not nearly as strong, of course, but different techniques can be used with different materials... like some Aluminum stuff. (although I have no experience with anything like that). It works best with steel and cast iron, though.

Here is a example of a man repairing a broken cast iron bandsaw bracket with brazing: YouTube - brazing repair of cast iron band saw bracket (http://www.youtube.com/watch?v=WE1wIpG0KnE)


------------------------

Personally I would use braze welding for most anything. I would avoid using it in especially critical areas like roll cages or suspension links... but stuff that would be difficult to weld properly and/or have more surface area to join would probably work out pretty well. I figure a proper braze weld that is easier to do right is better then a poorly done mig weld that was done too shallow because I was scared of burning through some metal.

Some things I think of off the top of my head maybe things like spare tire mounts. Non-critical 'cages' like 'exo cages' that are intended to protect your sheet metal and not main parts to protect lives. Stuff in metal dash boards. Brazing together metal to replace cut-out sections of bed or floor for rust repair. Adding on light brackets to cages. Repairing body mounts. That sort of thing. Anything were mild steel-level strength was plenty.

I imagine that having a mobile braze welding kit handy would be kick-ass for doing emergency repairs. Stuff like broken shock mounts, broken frames, broken suspension mounts. Broken-pretty-much-anything steel or cast iron. That sort of thing.

Like if a old jeep broke a section of it's frame. A half hour-to-a-hour repair with a stiff metal brush, a piece of leaf spring, and a couple metal clamps combined with braze welding will make something like that drivable again. Not safe enough to head down 75mph on the interstate or anything like that, but good enough so that it can get back home all nice-and-easy so that a proper repair can be done.

Of course carrying compressed oxygen around may not be the brightest idea, but if your going to do cook-outs with propane then a small propane torch and alone would probably be good for some ghetto-fab brazing.

Just watch out for gas leaks and gas lines and that sort of thing. Having stuff explode next to you would make for a VERY bad rest-of-your-life (however long that would be).


Just food for thought, that is all.

I am no expert. Just took some classes, did a (very) non critical part time job that involved some welding and that sort of thing. Nothing special, nothing that makes me a expert.

Nice community you guys got here, btw. Lots of useful stuff.

There is a ton of useful information in your post, if you hadn't included a web link to that torch kit I wouldn't suspect that you are a spammer pimping for toolfetch

There is a ton of useful information in your post, if you hadn't included a web link to that torch kit I wouldn't suspect that you are a spammer...

I don't know why the hell you would of thought that. But I deleted the link anyways. It's just something that looked like a reasonable example through google shopping.

If it really was faster, easier, and cheaper everyone would be doing it. So...Fail. If you have to use brazing, such as joining dissimilar metals or joining alloys that are damaged by high heat then it rules. Even for trailside repairs you'd be far better off with an alt welder in stick mode and without any of the danger of compressed flameable gas tanks sitting around. I love silver and bronze brazing as it's a real art to make them look perfect but the idea that I would chose to use it over using my TIG or MIG machines because it's a better process is absurd.

BTW, try brazing anything that weighs more than a pound or two with a Mapp/air torch and you'd better hope it's a very hot day or you'll be there all day doing it.

And what the hell kind of first post is that?

If it really was faster, easier, and cheaper everyone would be doing it. So...Fail.

It's pretty common, but there is a perception problem that it's a weak process. But it does get used all over the place depending on what your looking at and popularity is not much of a measure of technical prowess. It's something that is standardized by the 'american welding society' and all that sort of thing.


If you have to use brazing, such as joining dissimilar metals or joining alloys that are damaged by high heat then it rules. Even for trailside repairs you'd be far better off with an alt welder in stick mode and without any of the danger of compressed flameable gas tanks sitting around.

That is probably right.


I love silver and bronze brazing as it's a real art to make them look perfect but the idea that I would chose to use it over using my TIG or MIG machines because it's a better process is absurd.


I never said it was a better process then TIG welding. If you look at my post I said it's obviously weaker then TIG. I also said it's not suitable for critical parts like roll cages or suspension joints.

What I did say is that it's superior to poorly done MIG welding, or probably even average MIG welding from a lot of people with little experience, but if you are doing MIG right then MIG is going to have superior strength since it's actually joining the base materials. Braze welding is also fast and fairly cheap if you have the rig. As long as the surface is clean and your using flux then it's easy to get right and you don't have to worry about burning through the base materials and the strength is up there with mild steel.


BTW, try brazing anything that weighs more than a pound or two with a Mapp/air torch and you'd better hope it's a very hot day or you'll be there all day doing it.

Maybe. Like I tried to hint at Mapp/air is probably not hot enough for true braze welding, but it may work in a pinch. Mapp/Oxy would be hot enough for braze welding a lot of things; but my personal experience is with only Oxyacetylene welding and brazing.

And what the hell kind of first post is that?

It's a start? I like this forum and it has lots of useful information in it. I expected my post to be picked apart, which is perfectly OK.

Like I said I am not a expert and there are people here who are, so I expect it to be taken with the weight that it deserves.

"It's a start"

A better start would be posting about something you are an expert at or just asking questions.

Welcome to Pirate4X4.

Brazing is a dieing art, I can remember when every Auto Body repair man used IT. Damn,I getting old! Welcome to Pirate4x4. and Merry Christmas.:D

I hear the body guys are going to have to relearn to braze due to the odd alloys carmakers are using for body panels.

What I did say is that it's superior to poorly done MIG welding, or probably even average MIG welding from a lot of people with little experience

Not that I disagree with this, but what are the chances that someone who is poor at wire feed (since not all are MIG) is going to be proficient at braze welding?

Chances are they are poor at either process and where does that leave you?

If your such a big fan of oxy-acetelyne and somewhat obscure processes why didn't you include aluminum welding in there? Is that a bit too obscure?

Gus

I hear the body guys are going to have to relearn to braze due to the odd alloys carmakers are using for body panels.

Brazing is still dead. Most of the OEM as spec adhesives for joining panels these days.

Its a cool skill, but I think its been religated to novel trick status. Its great when you have dissimiliar metals and an old time who can do it. However, QA on brazing is difficult so it really is dying as an industrial method of joining. Most people will go an entire career and not need to braze something. Hard to say that about arc welding

Not that I disagree with this, but what are the chances that someone who is poor at wire feed (since not all are MIG) is going to be proficient at braze welding?


Well braze welding is just really easy. That's all.

You heat up the metal till it glows red a bit then melt the bronze into it. (I like to coat mine in flux or buy the stuff with flux on it)

If you mess up by doing it too cold and it globs up on you then just hit it again with some heat and flux and re-flow it. If you heat it up too hot and the base metal begins to melt the bronze with spit and smoke and you just back off till it cools down a bit and you go again. It's very forgiving. Worst case is you'd have to hit it with a wire brush and some more flux to clean the metal up to get rid of carbon build up or something like that.

Not much to master. I remember the instructor spent about 10 minutes talking about it and showed a example and pretty much everyone in the class got it on the first try.

Now if your doing something like sheet metal repair like at a autobody place then that would certainly take a lot of knowledge to master. Simply because the gas process spreads around so much heat that it'll be difficult to avoid warping and that sort of thing. But if your doing stuff with any thickness then your fine.

Also you don't have to be so careful about mixing and matching metals and that sort of thing. Like you can just take a random steel bolt from the hardware store and braze it another piece of metal to make a special tool and it'll be plenty strong as long as you clean it right. Or cut up a old wrench in half with a chop saw and add a extension or use some flat steel to make a special purpose tool for putting something together. Any mechanic probably has quite a few tools that are only really useful for one or two things and recycling saves money. If you want a common example of were it's used you can look at drill bits they'll use brazing/braze welding to attach a carbide bit to the end of a drill bit.



Chances are they are poor at either process and where does that leave you?

Well then that leaves you having to hire somebody who knows what they are doing!

If your such a big fan of oxy-acetelyne and somewhat obscure processes why didn't you include aluminum welding in there? Is that a bit too obscure?

Gus

Well I mentioned in the first post that it's possible to do some sort of aluminum brazing, but as far as really doing gas welding aluminum it only works for certain alloys and seems so difficult that you'd probably just be better off farming it out or learning how to use TIG and do it properly.

If you know how to do it, its a good process. I did it bare handed in school and it taught me to be a MUCH better TIG welder. Like was said, if you cant get the hang of MIG, no way in hell you are going to be able to gas weld. If you cant read the puddle in MIG, you wont get it with gas welding. Im sorry but heating the shit out of anything and adding filler IS NOT the "easier" way to do it.
It has its place, but in the offroad industry where the thickness of steel is .125-.750 in some cases, it just isnt the most proficient or logical.

I think the title should be "God of Braze Welding (For all those that don't know)" :flipoff2:

I hear the body guys are going to have to relearn to braze due to the odd alloys carmakers are using for body panels.
Just took the I-CAR class a week back, the new Toyotas are brazed at the qtr to parcel tray and at the rear body.:grinpimp:

Brazing is still dead. Most of the OEM as spec adhesives for joining panels these days.

Its a cool skill, but I think its been religated to novel trick status. Its great when you have dissimiliar metals and an old time who can do it. However, QA on brazing is difficult so it really is dying as an industrial method of joining. Most people will go an entire career and not need to braze something. Hard to say that about arc welding


Read above. Automakers are using body panels as structural members and replacement needs to be repaired and reassembled the way they build them. Not that a lot of panels are not glued but brazing is making a comeback. MIG brazing even.

Brazing is still dead. Most of the OEM as spec adhesives for joining panels these days.

Its a cool skill, but I think its been religated to novel trick status. Its great when you have dissimiliar metals and an old time who can do it. However, QA on brazing is difficult so it really is dying as an industrial method of joining. Most people will go an entire career and not need to braze something. Hard to say that about arc welding

x2 I agree.

Im still not really sure what the original poster was trying to get at/achieve with this post......? :confused:

x2 I agree.

Im still not really sure what the original poster was trying to get at/achieve with this post......? :confused:


Just informational. I say something, you say something. I learn. That's all. You can take away what you want.

-----------

Before I forget. If anybody does decide to try oxyacetylene; take a class on it first. Acetylene is extremely volatile and unless handled correctly it will explode on you. Not fun. Tanks suck and they are dangerous and how you handle them is important. Plus you need to be able to maintain your equipment; they have serviceable parts and need to be examined and properly taken care of. That sort of thing. Those aspects are not your friends.

To me doing gas welding is fun and I forget to mention stuff like that.

--------------


I found this:
http://www.aws.org/w/a/wj/2000/09/0015/index.html

Interesting and some of it applies to automotive-related things. Not everything in off road trucks is welding frames and suspension bits together. :)

I think the title should be "God of Braze Welding (For all those that don't know)" :flipoff2:I thought the same thing.

took some night classes.

I probably fire up the oxy-acetelyene torch to braze something at least once a month. In a farm shop there's usually something made out of cast iron that breaks and needs repaired. I have also used it many times to join pipe fittings to stiff steel lines to replace a section of harline with a rubber hose... Stuff like brazing steel barbed fittings to steel power steering lines to replace a bad section with powersteering hose. Or to patch pinholes in steel lines there is nothing better. It is definately not a dead art. I'm 24 and have been doing it since I was 16 or so and I'll definately teach my little boy how to do it one of these days. :D

I'll be 51 in 2 days.
Used to be the way a feller learned welding was to start oxy/acet. then stick, then mig.
I am now in a position I have to help hire mechanics.
If a mechanic tells me, "I can MIG weld fine, but I'm not too good at stick" that really means, "I can't weld worth a fuck".
If someone can't stick weld, they aren't going to understand what the hell is going on with a mig welder.
And you learn what is going on in a weld puddle really well with oxy/acet.
I have seen damn few body men that can weld worth a shit either.
Maybe 2 out of the 50 plus that I know.
And every one of them thinks they weld just fine.:shaking:

This whole post reminds me of the Henrob torch. (http://www.cutlikeplasma.com/). That little bugger is impressive. I have Mig, Tig, Stick, Plasma and a propane torch but I still think having one of those Henrobs would be cool. (maybe I'll find one in a yardsale or something 1 day).

There is an almost cultish following on those things and their usefullness for various tasks. Watching some of the videos is educational of the potential the tool has to offer.

I'll be 51 in 2 days.
Used to be the way a feller learned welding was to start oxy/acet. then stick, then mig.
I am now in a position I have to help hire mechanics.
If a mechanic tells me, "I can MIG weld fine, but I'm not too good at stick" that really means, "I can't weld worth a fuck".
If someone can't stick weld, they aren't going to understand what the hell is going on with a mig welder.
And you learn what is going on in a weld puddle really well with oxy/acet.
I have seen damn few body men that can weld worth a shit either.
Maybe 2 out of the 50 plus that I know.
And every one of them thinks they weld just fine.:shaking:

Thats how the local community college is. 1st class is oxy/fuel and stick. This is the pre requisite for ANY other classes.
I learned gas, stick, mig, tig and I consider myself good at all of them.

Yeah that was what it was like for the school I took classes at. Although my main goal was just to learn gas.

The people that impressed me the most were ones that were training for the top arc welding classes. Doing stuff that was required for welding together big gas transport pipes. One of the big tests they had to do was weld together these two massive pieces of metal. Thicker then the palm of my hand was wide. They had to cut them so that the join was at 45 degree angles and they would spend a huge amount of time stuck in a little booth just overlapping their welds one after another to fill up the gap. Just dozens and dozens of overlapping welds. Then the instructor would cut the completed object lengthwise across the weld. If there was any slag or voids in their welds then they failed. That seemed godlike at the time.

Yeah that was what it was like for the school I took classes at. Although my main goal was just to learn gas.

The people that impressed me the most were ones that were training for the top arc welding classes. Doing stuff that was required for welding together big gas transport pipes. One of the big tests they had to do was weld together these two massive pieces of metal. Thicker then the palm of my hand was wide. They had to cut them so that the join was at 45 degree angles and they would spend a huge amount of time stuck in a little booth just overlapping their welds one after another to fill up the gap. Just dozens and dozens of overlapping welds. Then the instructor would cut the completed object lengthwise across the weld. If there was any slag or voids in their welds then they failed. That seemed godlike at the time.

Generally you would perform a single U weld to avoid that much filler but for a test it would be fun

In hard spots we will oxy weld the tubes in D type water boiler's, but for most things we just use stick and mig

Oxy is good however you are putting in a massive ammount of heat which can affect the job, generally you have the largest HAZ with oxy then arc, mig, tig and so on

The first two jobs I had that required me to be able to weld were all gas. The first one was making oil fill tubes for Harvester trucks, the second, repairing airplane motor mounts.

Now, the gas axe is only used as an axe! There are better tools today.

Now, the gas axe is only used as an axe! There are better tools today.

Well the reasoning at the time was that with gas I can do pretty much anything. I can cut and weld and heat metal and do all sorts of different things with it.

For example.. I live in the rust belt so when working on something under the car it's bolts are usually rusted up pretty badly. So if I can't get a bolt off I can heat it up pretty hot and it'll usually come off. Or if I round a nut by mistake I can quickly braze on piece of something that I can get my vice grips around. I can cut off a bolt or use it to 'predrill' a hole so I don't have to waste a bunch of small drill bits.

Just things like that. So it's a nice 'multitool' and while it's not superior at lots of things it can still do lots of things.

Now if I was serious about being a professional or something like that then I would of put more time into it and learned how to stick weld really well. I understand that time is money and there are quicker and more efficient ways to get stuff done. But I did not pursue that as a carreer path. The way things are right now I'd rather just use something like a hacksaw and a file instead of putting a big investment in more expensive more specific purpose stuff.

Well the reasoning at the time was that with gas I can do pretty much anything. I can cut and weld and heat metal and do all sorts of different things with it.

For example.. I live in the rust belt so when working on something under the car it's bolts are usually rusted up pretty badly. So if I can't get a bolt off I can heat it up pretty hot and it'll usually come off. Or if I round a nut by mistake I can quickly braze on piece of something that I can get my vice grips around. I can cut off a bolt or use it to 'predrill' a hole so I don't have to waste a bunch of small drill bits.

Just things like that. So it's a nice 'multitool' and while it's not superior at lots of things it can still do lots of things.

Now if I was serious about being a professional or something like that then I would of put more time into it and learned how to stick weld really well. I understand that time is money and there are quicker and more efficient ways to get stuff done. But I did not pursue that as a carreer path. The way things are right now I'd rather just use something like a hacksaw and a file instead of putting a big investment in more expensive more specific purpose stuff.

Buddy why don't you start a thread in the appropiate forum and tell us about your truck this is getting pretty stale:rolleyes:

Well the reasoning at the time was that with gas I can do pretty much anything. I can cut and weld and heat metal and do all sorts of different things with it.

I understand that time is money and there are quicker and more efficient ways to get stuff done. But I did not pursue that as a carreer path. The way things are right now I'd rather just use something like a hacksaw and a file instead of putting a big investment in more expensive more specific purpose stuff.

LOFL, what are you 12? You type as though you just discovered your dick and wanted to tell everybody about it. What you're saying in this thread, I'd bet every one of us knew the second time we picked up a torch.

As for career path, that path is long and winding, you never know where it will take you, however, if you act and talk like this at work, you'll do fine asking if orders should be super-sized.

I was willing to give you some support, but perhaps you should lurk around here some more.

I'll lurk around some more and I'll definitely show my truck when I got something to show for it. It's been a few years since I last did 4x4 stuff recreationally and I recently acquired a old SamuraI that I am intent on fixing up. Right now it's very uninteresting since finances are low and I have been putting most of my effort into just putting it back into proper working order.

I don't need anybody's support though. It's not really a big deal either way to me what people think of this thread. It's just a way to pass the time and get feedback from people that are much more experienced then me.

Thanks though. Actually thanks to everybody. Don't think I am not listening to what is being said.