brazing question

[mendozer]

I've been watching videos on silver soldering (or brazing) copper to stainless. I've read that it can be tricky or that it's finicky. However I'm watching these videos and it doesn't look that hard, unless I'm missing something.

Put flux on, heat it up, maybe more flux, silver solder, then let cool.

I'm not getting why it's that much more difficult than regular soldering.

[pythonshine]

The diffrant materials heat at diffrant rates. Get the flux hot enough to burn...gotta start over. Propper flux. Prepwork. It is easy once you have the basics and have done it a few times.

[skow69]

Playing the cello looks easy when you watch Yo-yo Ma do it.

[mendozer]

oh ok so if using the right flux (I've seen harris stay silv a lot of places) and heating stainless first, then it should be doable.

Also:
1) I assume it'll be easy to test the final product by either torquing the joint or seeing for liquid leakage
2) to save on supplies, can I use copper to stainless silver soldering specific solder and flux for regular copper to copper soldering? and stainless to stainless soldering?

[mendozer]

Playing the cello looks easy when you watch Yo-yo Ma do it.

Hah true. I'm a quick study so I'll try my hand at this. Think I'll try MAP gas instead of propane too.

[pythonshine]

Map works well harris liquid flux is your best bet. What are you using for solder?

[Swedish Pride]

oh ok so if using the right flux (I've seen harris stay silv a lot of places) and heating stainless first, then it should be doable.

Also:
1) I assume it'll be easy to test the final product by either torquing the joint or seeing for liquid leakage
2) to save on supplies, can I use copper to stainless silver soldering specific solder and flux for regular copper to copper soldering? and stainless to stainless soldering?

What are you going to braze?
I went with just silver solder, we don't need braze for most applications in the stilling building.

No experience brazing, not sure if there is one rod that can do it all.
I would just get harris stay clean flux and some lead free solder or 5%silversolder, that will cover SS to copper , copper to copper, ss to ss
If you are doing SS to copper it's better to heat the copper only and let the copper heat the ss.

[pythonshine]

Its copper to Ss there SwedishPride. I also think he means soldering.

[mendozer]

I don't have supplies yet, have any recommendation? brazing rod, solder?

harris stay brite #8?

[pythonshine]

The stay bright #8 will serve you well. The problem with brazing is the high temp. For example harris stay silv 5 becomes liquidus at 1500·f. IMHO i would stick with the stay brite 8. Cheers...good luck and keep on keepin. Let me know if you have any questions.

[Hound Dog]

The stay bright #8 will serve you well. The problem with brazing is the high temp. For example harris stay silv 5 becomes liquidus at 1500·f. IMHO i would stick with the stay brite 8. Cheers...good luck and keep on keepin. Let me know if you have any questions.

+1. I solder stainless to copper or stainless using Staybrite8 and liquid flux. I find the trick is to not heat it too much. I turn my torch down very low and gently heat so I don't burn the flux. Once it is hot enough to melt the solder, I douse it with more flux and it etches really good. I continue heating and melt solder in the joint. Works like a charm. Oh yea, prep is vital. I prep mine with sanding disks on a die grinder so it scuffs the hell out of the stainless.

[mendozer]

k so flux, heat slowly then once solder collapses and melts into the joint, squirt or brush on more flux to finish? good deal

[Hound Dog]

Squirt flux for sure. Use liquid flux, not paste flux.

[pfshine]

Remember copper takes more heat than ss. Stainless is greedy and keeps all the heat you give it, copper wants to give it all away.

[Yummyrum]

Mendozer.
Brazing is where you heat the metal to RED hot , use a borax based flux and use a HARD rod .
You DO NOT WANT to do this .It will scorch your stainless ferrules.

What you need to be doing is SOFT SOLDERING using a low heat ,a zinc chloride based flux and lead free soft solder which usually contains a small amount of silver but not always .

Low gental heat is betyer and concentrate on heating the copper not the staino .
The staino must be imaculately clean.

[mendozer]

Silver soldering occurs under 800 F right? I have an infrared thermo gun I can use if I have a target temp for this. If this helps identifying when the metals ready.

So heat stainless first since it's greedy then hit the copper? Or hit the copper first and let it heat stainless. I've seen both methods.

[pfshine]

Copper first. Keep the heat moving all around, heat the copper mostly and dip into the ss. Do a couple trial pieces first.

[Yummyrum]

+1
Heat the copper first and mostly. Don't worry about thermometers. The trick is to watch the flux.
The flux will start to splutter and boil at about the right tempas the heat at the copper/ staino jnction is right .At this point , brush on more flux and wipe the solder on the joint.If it wont instantly melt on contact , you need a bit more heat.
Once the solder starts to flow into the joint , apply only the bearest amount of heat to keep the joint warm..
A big fluffy gentle flame is the go.A roaring pin point flame is hopeless.
I use my Mapp toch on my propane bottle because the Mapp is too hot but the propane toch is too focused.

[corene1]

Silver brazing and silver soldering are 2 completely different animals. Silver braze is typically at a high silver content most are around 45% silver give or take a bit and flow at 1125 plus degrees. These require a high temp flux usually a paste flux that is active from 800 to 1800 degrees. A liquid flux such as Harris stay clean will burn at those temps. While silver soldering is usually done with a solder with a very low silver content, Stay Brite 8 has 6% silver and flows at 525 degrees so it will work well with the Harris stay clean liquid flux. As was said before the copper will need more of the heat than the stainless since the stainless will hold onto the heat while the copper is dissipating it, heat distribution is critical. Cleanliness is crucial also. make sure all your joints are clean and even rough the surface a bit on the stainless I typically use a clean file to prep the stainless as it leaves no residue like and emery cloth or a contaminated wire brush will.

[mendozer]

awesome thanks for all the help folks. I won't have any stainless to practice with really. I'll just do it and if it's not nice or done well I'll try to re-melt the solder or just cut the copper off and get another stainless TC flange.