Talk:Brazing

message: Hi,
I just wanted to say that the example given, with Nitinol and Niobium, is a very bad one.
An excelent example for an eutectic alloy is Cusil (a Copper-Silver alloy) , which is a very common brazing filler metal. 
If indeed Nitinol and Niobium form an eutectic it is not a simple one and i wouldn't give it as an example. I would also like to say that I find it hard to believe that Nitinol is a material regulary being brazed. At brazing temperatures (above 450C) Nitinol goes through extensive heat treatment and a radical change in properties is observed.It is possible that in certain specific applications Nitinol brazing is done, but as i said, not regulary. Also for this reason i find it
a bad example for the introduction of "Brazing" .  —Preceding unsigned comment added by 79.177.128.185 (talk) 15:35, 24 November 2007 (UTC)
replies: text: Welding will often distort the original metal part, although the final (warped) item will have nearly uniform strength with the original metal part.  Brazing, on the other hand, causes no distortion of the original metal part, but is still roughly 1/3 as strong as if welded.  In many cases, this is strong enough, and the avoidance of distortion in the original metal parts is the key reason for using brazing instead of welding. Yaf 22:46, 8 February 2006 (UTC)

message: Under Silver Brasing, there is the line "Pretinning gets around the problem that hardmetals are hard to wet."   What does that mean?  Literally wet, with water?  Or does it mean whet, not wet?  Could somebody please clarify/explain?  Thanks. 24.78.106.209 (talk)  —Preceding comment was added at 05:23, 12 July 2008 (UTC)
thread_title:  "Hard to wet" 

message: Im going to be re-working the advantages section and adding references.
--Pocketpencil (talk) 17:33, 26 August 2009 (UTC)
thread_title:  Advantages 

message: I will be reworking the disadvantages and the processes section next.  After that i think the whole article needs more work, and additional references added.  Some of the examples used are poor and do not adequately describe or characterize brazing.  It also feels like very slanted towards torch brazing, with little insight into industrial brazing which occurs quite frequently.  I will also try to make the article more general with regards to the theory of brazing.  It seems there are many rules of thumb and anecdotal evidence given, many of which are incorrect.  Will update when completed --Pocketpencil (talk) 16:58, 28 August 2009 (UTC)
replies: text: Everything done except techniques section, should have time to get to that in a day or so. --Pocketpencil (talk) 21:34, 18 September 2009 (UTC)
replies: text: All finished...let me know if something needs editing/revising --Pocketpencil (talk) 14:25, 22 September 2009 (UTC)
replies: text: I have restored all of the "common technique" subsections that were deleted because those seem like legitimate brazing techniques to me, unless I'm missing something. I think the vacuum section needs to be merged into the vacuum furnace section to reduce redundancy, otherwise the rest only need references. I've also added a  and  template to the sections that need the respective clean-ups. Hope that helps. Wizard191 (talk) 20:27, 22 September 2009 (UTC)
replies: text: They are not legitimate brazing techniques.  They are all special types of torch brazing.  Vacuum brazing can be merged with the furnace section (though there is some incorrect info in there), but the other 3 techniques (braze welding, cast iron and silver) are all torch brazing with different substrates of fillers.  calling these brazing techniques is incorrect.  Perhaps a section could be created listing some special types or applications of torch brazing and then incorporate some of these there.  Not only that, but the sections seem to have a lot of anecdotal type statements which dont really contribute to an understanding of the brazing process. --Pocketpencil (talk) 22:24, 22 September 2009 (UTC)
replies: text: Also, the sections you added the expansion and cleanup templates to were already cleaned up by me.  There is not much else to go into there unless you want this article to be really long and drug out. --Pocketpencil (talk) 22:27, 22 September 2009 (UTC)
thread_title:  Further rework 

message: The mains points coming out are the higher temperatures in brazing compared to soldering. 
But this has the affect, from the operators point of view of greatly changing the tools used. In my experience hand brazing uses some form of gas torch that applies the flame directly to the work pieces. 
Soldering, especially for electronics, would almost always use a small (<5mm) tipped soldering iron. Usually electric, but sometimes the tip is heated by butane or similar gas. But the gas flame is NEVER (for cicuit board work anyway) applied directly to the surface. One exception might be where a steel chassis is having items soldered directly to it. Even that would be uncommon now days. The heat has to be applied very precisely, or your component or circuit board would be destroyed. 
--220.101.28.25 (talk) 10:21, 25 October 2009 (UTC)
thread_title:  Soldering vs Brazing 

message: In an otherwise useful article, no mention is made of the use of the oxy-acetylene process  commonly used with brazing. More specifically, what flame should be used, oxydising, nuetral or carburising?  —Preceding unsigned comment added by 212.93.199.154 (talk) 07:02, 19 January 2010 (UTC)
thread_title:  Heating 

message: In the most general way, it is not possible to give you specific recommendation on the flame adjustment to use.  This depends upon the base metal, filler metal and type of flux.
In the most theoretical way and to be safe, go for neutral to slightly oxidising.  Normally, oxidizing is the best.  Think of it this way - you use a flux in order to clean the oxides off the base metal.  If you use an oxidizing flame, you help the flux by also using the oxidizing flame.  In contrast, if you clean the surface with a flux and then keep getting it dirty with a carbarizing flame, well you are defeating the purpose of the flux.  
But this rule of thumb is not always true.  So to be on the safe side, go for neutral flame.  But when the base metal and filler metal support it, oxidizing is the best way to go.  —Preceding unsigned comment added by 178.198.133.52 (talk) 20:57, 12 October 2010 (UTC)
thread_title:  General advice on flame

message: wish I could easily give appropriate references.  Maybe I can email offline with the author of this article and revise the main text.  I am not sure how this process works.  Wish I could sign it also so you could contact me, but I am not sure how to do this.
There are alot of references in the text and I am 100% sure that some of them must contain required info.  Any brazing book with its weight in peanuts will give the famous graph of tensile strength as a function of the brazed joint.  They all have this !  It readily shows for large gaps, the strength of the joint will drop down to the tensile strength of the brazing filler metal.  While these are often soft (soft solders, silver alloys, pure copper), they must not be. Think of Ni-base braze where strength is rather high and alloys are brittle.
Anyhow, this is common knowledge of anyone with practice in brazing.  Take really any combination of materials, and do a proper braze joint. Do a tensile test and you see easily that you break in the base metal.  Always.
I have been out of academic studies 20 years and no longer have access to my text books or library.  But my PhD in metallurgy gives me good reason to believe that I make no mistake here.  The explanation for this is also pretty easy to find.  You get any sophmore level book on mechanics of dislocations.  When you look at the influence of the stress state on deformation, you see that when you constrain deformation to two dimensions you get infinitely increasing strength.  A narrow brazed gap has the same effect and creates this two-dimensional stress state within the braze material.  
So theory readily explains what is empirically observed and it all makes sense.
BRAZING gives the highest strength joining technique that we know (compared to welding, gluing, rivets, etc).  —Preceding unsigned comment added by 178.198.133.52 (talk) 21:07, 12 October 2010 (UTC)
thread_title: References on strength

message: I can probably provide some references for brazed joint strength:
Design_and_strength_brazed_joints
see fig 7 and associated paras for showing that silver-copper (the most widely used brazing alloy) can exceed both the UTS of Silver, coppper AND steel.  There are other reasons for this other than just "because it is brazed not welded".  Firstly it involves triaxial stresses associated with brazed joints; in a very narrow joint gap the filler metal will be prevented from necking, which if you study your fracture mechanics is an important part of the fracture mechanism.
A whole host of our literature is available here:
JM_literature
If anyone is interested in further reading.
Here is a slide taken from a presentation I have given:
slide
NOTE: these are NOT test results, I have mocked this data up from test results (just quickly from a presentation).  I just thought it was a nic graphical way to articulate the effect I am trying to describe.
I can be contacted directly at will.clark@matthey.com if more sources/source verification is required.
Regards,
Will
E4xit (talk) 11:23, 27 January 2012 (UTC)
thread_title: References for brazed joint strength

message: I suppose the temperature difference may be the "accepted" dividing line, however there are fundamental differences between soldering, brazing, and welding with regards to the ways those techniques are used. In traditional soldering, a physical connection is first created between the 2 pieces to be joined (two wires twisted together to make an electrical contact, a component attached to a circuit board by its leads, copper plumbing and a tight fitting). Then the work to be joined is heated to a temperature above the solder's melting point and solder is brought into contact with the work. The solder stabilizes the existing physical bond and prevents oxide from forming and the conductor-conductor contact point remains highly conductive. (Note that modern electronics uses very low currents so the higher resistance of conduction through solder or high resistance circuit traces are less relevant. Most manufacturing uses solder paste adhesive or silver epoxy for physical contact and conduction.)  Brazing is used to create a strong physical bond between two pieces to be joined and it is the braze that is heated to melting and not the pieces to be joined. (Hence your confusion in calling some brazes "high temperature solder".) Welding. Construction welding e.g. 8" steel beam to 6" thick 6' diameter steel tube uses filler metal similar to the pieces to be joined and melts both the filler metal and the surfaces of the metals to be joined. Thinner pieces can be melted/joined without filler metal. Indeed metals will weld when held against each other under pressure at well below their melting point: like spot welds or picking up a 1000°C Platinum crucible with Iron tongs. I spent some years working at an Industrial Testing Laboratory doing failure analysis for legal cases. The distinction between soldering and brazing was important for a deposition I did. The Testing Lab had subscriptions to ASME and ASTM documentation, and non-web NIST or ANSI information was free. These Standards agencies now charge several hundred dollars for information. (I note that a majority of citations here come from "Industrial brazing practice - Google Books. Books.google.com. 2004. . http://books.google.com/?id=LHOsJGu9WUAC&pg=PA272&dq=brazing+alloys+types&cd=1#v=onepage&q=brazing%20alloys%20types" which is NOT in the public domain and refer to pages not even displayed by Google.) Very good information about brazing et al can be obtained from Copper.org, most documents being free/gratis or a token $1
Shjacks45 (talk) 21:04, 1 November 2010 (UTC)
thread_title:  Side note re soldering vs brazing 

message: Hi,
I've rewritten the lead and will be back in a week or so to remove the flag. In addition added proper names and links to the various filler materials for clarity.
Marc — Preceding unsigned comment added by 80.219.53.103 (talk) 10:26, 9 May 2015 (UTC)
thread_title: lead

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message: As far as I know, retort furnaces cannot be used "semi-continuously" due to the nature of the retort -- it must be run in a batch. I don't have any citations to back this up, but it seems obvious to me from my experience and reading of the article.65.24.142.205 (talk) 13:55, 1 December 2021 (UTC)
thread_title:  Dubious 

message: This article has no history. I wanted to know the history of brazing, but there is nothing significant in the article. It would be good if someone who knows anything about this topic could add a history section.
Lkingscott (talk) 12:42, 7 April 2023 (UTC)
thread_title:  No History