need massive info dump on solder/brazing

[drysdam]

I want to attach metal together. Generally small pieces of brass, aluminum and steel. I don't want to use glue. At least some of these connections may be heated to some degree.

I keep reading about brazing, soldering, silver soldering and other terms but everyone seems to using these words very loosely with no particular indication of what materials or torch types they are using ("propane isn't hot enough" doesn't educate me very far and "an ordinary blowlamp" is hard to shop for where the rubber meets the road). It doesn't help that even when speaking more strictly the terms seem to differ on opposite sides of the pond and from different historical periods.

What I need is a comprehensive source of information that will tell me more than I need to know, starting at the beginning, in modern US terminology. With a firm foundation, I will then be able to ask intelligent questions and be able to tell when the answerer doesn't know anything either. Does anything like this exist?

(I don't think I'm interested in welding, but it may be that the information I'm looking for would be part of a curriculum that included welding. That's fine.)

 

[Troutsqueezer]

Getting information that is tailored specifically to one's education, experience and level of intelligence is something we all would like access to. Unfortunately, the world doesn't work that way. You're off to a good start by accessing this forum. Use the search tool here and use Google in general and cull the information as it applies to what you are seeking.

Folks here are always happy to answer specific questions.

 

[mklotz]

And to add to what Trout said...

Describe your particular application here and you'll get expert advice from the membership. Do that several times and you'll have lots of material from which to generalize.

Also, don't dismiss other methods of joining two pieces. Loctite adhesives are a boon and interference fits are often the way to go.

 

[drysdam]

I'm a little skeptical that this information only exists as folklore. Also, I'm still too ignorant to even ask a question (e.g. to know what is even relevant). Is there at least a starter kit of info somewhere? I've tried the "Soldering and Brazing" book by Tubal Cain but it is either too old or too "foreign" (or both) to impart any information to me.

Basically, I'm looking for a "for Dummies" level intro to get me up the level where I can bootstrap myself farther.

 

[rhitee93]

Very generally:

Soldering or soft solder uses a filler material that melts in the 400-500 degree F range. This can be done with an electric iron, small torch, or a variety of other heat sources.

Silver Solder uses a filler material that melts at a much higher temp. 1000 deg F or more. As such it requires a bigger torch. It is a stronger filler material, and produces a stronger joint that is also more temperature resistant.

This link might help you a bit:
http://en.wikipedia.org/wiki/Soldering

Brazing is more like silver soldering, but I usually think of it as an even higher temperature operation. I don't braze often, so I won't speculate any more than what I have already. However, going to the same source as above may be helpful:
http://en.wikipedia.org/wiki/Brazing

One thing is that aluminum generally doesn't solder or braze at all. There are probably some exceptions for certain alloys and filler materials, but in general it isn't an option.

 

[drysdam]

Is glue or fasteners the only option for (most) Al then?

 

[Blogwitch]

There is no such book as soldering for dummies, purely because as already mentioned, every job is different, and I for one wouldn't like to teach a dummy to silver solder.

Just knowing where you come from helps, as US English and terminology is , when it comes to soldering, totally different to UK English.

In the US they say silver soldering, and it is a very soft solder like plumbers use, whereas we in the UK we would call it soft soldering, and it is also common in the US to call our silver soldering, silver brazing, a hard soldering process that usually uses butane torches to reach the temperatures required.

To write a complete topic on the differences of solders and techniques is not a thing I would relish, I could be there for weeks.

As already mentioned, do a search for "silver solder", in quotes, as I have put it, and you should come up with a lot of articles on this site describing the technique. I know for a fact that I have described techniques many times.


John

 

[Rayanth]

MIG welding is another option if you really feel you need a metal bond (Aluminum-Aluminum)... but it's not really a do-it-yourself hobbyist option as far as I'm aware.

- Ryan

 

[drysdam]

I'm looking at brass/aluminum for my current project. Parts around the diameter of a pencil and mostly smaller.

<i>In the US they say silver soldering, and it is a very soft solder like plumbers use, whereas we in the UK we would call it soft soldering, and it is also common in the US to call our silver soldering, silver brazing, a hard soldering process that usually uses butane torches to reach the temperatures required.
...
As already mentioned, do a search for "silver solder", in quotes, as I have put it, and you should come up with a lot of articles on this site describing the technique</i>

It sounds like I'd find articles describing at least two techniques. On a hard process in the UK and one a soft one in the US. Which one are you intending me to find and how do I distinguish them? Text doesn't always have an accent...

 

[sunworksco]

Here is my friend Ken, "The Tin Man".
Watch his video hard soldering aluminum.


[ame]http://www.youtube.com/watch?v=RRWmpSE-hXk&feature=youtube_gdata_player[/ame]

 

[rhitee93]

Is glue or fasteners the only option for (most) Al then?

There are many mechanical methods. Fasteners of all kinds, or interference fits as Marv mentioned. Regarding adhesives, some of the epoxies out there are amazing!

I'm looking at brass/aluminum for my current project. Parts around the diameter of a pencil and mostly smaller.

There is no metallurgical way to bond brass and aluminum that I know of. If this is what you are needing to do then I thik you are stuck with mechanical connections or adhesives.

 

[steamer]

Under 300F I wouldn't worry too much about model parts held together with Loctite.

On the other hand.....I wouldn't loctite a boiler together!.....

There is no substitute for good engineering judgement!

What is the application?


Dave

 

[pkastagehand]

My experience with US terms is that silver soldering (or silver brazing) are not related to soft soldering (lead and modern lead-free substitutes) used for electronics and plumbing.

Silver soldering is technically a "brazing" process because it happens at a higher temperature than soft soldering. I don't know those temps offhand but brass/bronze and silver brazing materials melt in the range of 1600 degrees F to 2200 deg. F. So unless the part is small you need something that has first off a high enough temperature and second puts out enough BTUs so that the parts heat faster than they conduct the heat away.

That is why a small plumbers propane torch often doesn't work. It will get hot enough to melt silver solder, but if the parts are very big they conduct the heat away too rapidly to get the base metal up to temperature.

I mostly use the oxygen-acetylene torch for silver brazing because that is what I have.

Some folks have bought Turbo(TM) torches or similar that use propane as fuel but design allows them to put out more BTUs than the little hand helds. They generally hook to a larger tank and use a hose.

Aluminum can be brazed, but like welding it, it can be a trickier project for two reasons. Aluminum oxidizes almost instantly. So you clean it but before you get the torch lit it has a skin of oxidation on it already. So fluxes, etc. are very important (as they are in all metals but maybe more so). Also, aluminum doesn't change color just before it melts like many other materials do.

Welder's Handbook by Richard Finch is a nice source of info for basic welding information and includes soldering brazing info.

Welding by Robert O'Con is another book.

Paul

PS I should also have mentioned that Kozo Hiroaka in his A3 book and possibly the others as well has a section devoted to explaining the mysteries of silver brazing.

 

[rhitee93]

Here is my friend Ken, "The Tin Man".
Watch his video hard soldering aluminum.

That was impressive! I've tried the "Flea market special" stuff he mentions and it is utter crap.
Your friend makes it look easy :bow:

 

[steamer]

My experience with US terms is that silver soldering (or silver brazing) are not related to soft soldering (lead and modern lead-free substitutes) used for electronics and plumbing.

Silver soldering is technically a "brazing" process because it happens at a higher temperature than soft soldering. I don't know those temps offhand but brass/bronze and silver brazing materials melt in the range of 1600 degrees F to 2200 deg. F. So unless the part is small you need something that has first off a high enough temperature and second puts out enough BTUs so that the parts heat faster than they conduct the heat away.

That is why a small plumbers propane torch often doesn't work. It will get hot enough to melt silver solder, but if the parts are very big they conduct the heat away too rapidly to get the base metal up to temperature.

I mostly use the oxygen-acetylene torch for silver brazing because that is what I have.

Some folks have bought Turbo(TM) torches or similar that use propane as fuel but design allows them to put out more BTUs than the little hand helds. They generally hook to a larger tank and use a hose.

Aluminum can be brazed, but like welding it, it can be a trickier project for two reasons. Aluminum oxidizes almost instantly. So you clean it but before you get the torch lit it has a skin of oxidation on it already. So fluxes, etc. are very important (as they are in all metals but maybe more so). Also, aluminum doesn't change color just before it melts like many other materials do.

Welder's Handbook by Richard Finch is a nice source of info for basic welding information and includes soldering brazing info.

Welding by Robert O'Con is another book.

Paul

PS I should also have mentioned that Kozo Hiroaka in his A3 book and possibly the others as well has a section devoted to explaining the mysteries of silver brazing.

Above 800F is technically the dividing line between "soldering" and "brazing"......In the US Silver Soldering is called that regardless....and I've seen heated arguments about the name....but lets not..... :

Dave

 

[drysdam]

I'm not <i>worried</i> about parts glued together. I just don't want to use it. I'm sure it's easier but if I were looking to ease my workload I wouldn't be in the hobby in the first place. Doing the hard way when it seems more "right" to me is fine.

But you guys can already see what I'm talking about in this thread and we're not even 20 posts in. "You can't braze Al" vs "Here's how you braze Al" vs "the term for this is X" vs "the term is actually Y under circumstance Z".

I'd really rather avoid wading through hundreds of (apparently?) contradictory posts without any way to tell who actually knows what they are talking about. I need modern, US-oriented, definitive source.

 

[steamer]

Here ya go!

http://www.aws.org/w/a/

Dave

 

[clivel]

The latest flyer I received from Camden Miniature steam advertises a book called "Welding Know-How" by Frank Marlow.

Quoting from the sales blurb "here is one book which covers every aspect of soldering, brazing, welding and cutting by electrical, gas and combined means" it would seem to answer most of your questions.

More info from Camden http://www.camdenmin.co.uk/new-items-after-booklist-65/welding-know-how-p-3556.html
Or if you are in the US directly from the publishers http://www.metalartspress.com/wkh.html

 

[drysdam]

Thanks, I'm getting a book similar to that from the library. It looks like only a chapter is devoted to things that aren't strictly welding, but maybe that will be enough.

The AWS website was a good idea, but I don't see anything there that isn't about welding.

 

[Bustedbricks]

It's much easier to state a specific application and work from there. What method you use to join metals depends a lot on what it is you want to achieve.

Alu can be MIG, TIG and MMA welded with the right equipment. You can also solder alu with specialised flux and solder. However you cannot join it with other metals using these metals as has already been mentioned.

Brass, copper and steel can be soft soldered, silver soldered, bronze brazed etc. The method selected depends on desired strength, temp resistance, assembly sequence etc. There are so many variables.