I decided to post a few pictures and a bit of information on this really useful metal joining process
this is the flux I like to use
flux applied to 1/2 of the pieces I am joining
and here is flux on the other part I am joining
And a few minutes later here they are joined together
This process is used in lots of places (like hydraulic fittings for one). If you spend anytime looking at complicated metal objects you will see the telltale silvery coloured joint line
These parts are for a front disc brake assembly for a model T
Are you using oxi-acetylene, mapp gas or ?
I used oxy-acetylene. I'm sure MAPP would work well too
As long as I can get to about 1000-1100 F reasonably quickly
Ok guys, You need to pay attention as to the solder. Some is 2% some is 45% and some is 56%. The 2% melts at around 425 degrees and is mostly lead. The 45% is good stuff and as Les said melts at around 1025 degrees. I found out that you must clean with acetone apply the flux and then let the flux dry. Things will work out very well then. Let the part melt the solder not the flame. When the temp is right the solder will flow great. Good luck, Scott
To add. I prefer to only apply the solder on one side of the joint. This way I can see when I get "returns " on the other side of the joint. Then I can be satisfied that I likely have a complete bond in the joint
A big advantage of silver brazing is that folks can use it with just a propane torch. Works on steel, iron, sheet metal, stainless steel, brass and copper or any combination. It is quite strong.
Here is a copper scoop silver brazed to a steel mag post fitting.
This is a process that is VERY home shop "friendly ". You can achieve really strong joints with no distortion and little cleanup required
Fairly easy to learn. You can get a "full penetration " connection that is leak proof
With welding you have a tougher time getting a full penetration joint and will likely get more distortion
Yes welding has it's place, but so does this process
Just to add a little more info about silver soldering - You can purchase (as was noted by Scott) several variations of silver solder with different silver content resulting in increasingly higher melting points, from "Extra Easy" (56%, 1145* MP) through "Easy", "Medium", and "Hard", up to "IT" (80%, 1340* MP). These are typically what's used in jewelry fabrication and other silversmithing processes. The various content levels and melting points allow for multiple soldering operations on the same piece, using "Hard" for the first, "Medium" for the second, etc., with subsequently lower melting points.
Regarding the soldering operation itself; the sheet solder can be cut into very small squares and the squares then placed appropriately into the wet flux where the joint will be. Once the flux and solder is placed, allow the flux to dry, holding the solder squares in place. Then, as was noted, heat the surrounding area of the joint rather than the solder itself. If your solder "balls-up" rather than flowing, one of three things has occurred; either you're heating the solder and not the pieces to be joined, your flux isn't applied properly, or your pieces to be joined aren't cleaned appropriately.
Silver Soldering is highly dependent upon the specific application and type of metals being soldered.
Try this website Muggy Weld it has many different products (various tinsel strengths and flux types/methods) and excellent videos depicting the use of each product.
I use silver soldering to strengthen the commonly failed pinned filed winding buss bar to terminal bolt connection on the Model T starter.
Ron the Coilman
Muggy weld is a good source. Not as good for me, being Canadian. I did recently buy some from them that is specially formulated for work on cast iron, as I am working up a installation of port fuel injection on my '81 351 M powered F150. I need to install 8 injector "bosses" to a cast iron intake manifold.
I just buy my supplies at the local welding supply store. And yes it is the '45' wire.
A couple of years ago I used this process to assemble my auxillary radius rod as part of the front brakes on my '27 roadster.
I'll take some pictures
I have used lots of silver braze over the years. The one I like is the 45% silver. It is strong and will "wick" into the thinnest of joints. It works well on brass, steel, and stainless. I use an oxy/acet torch.
On a daily basis we silver braze Cu/Ni heat exchangers for the Maritime Industry. There are a couple of rules and precautions when silver brazing.
The joint gets it strength from it's capillary action and not a fillet.
Surface prep is critical. We wipe the parts with Acetone then either power wire brush with a SS wheel, or grind the surface with a ceramic coated disc. Brazing does not like oxides.
The roughness of the grinding does help with the "wetting" allowing a better capillary action. A small tight joint is stronger that a wide or thick joint (clamp tightly).
Fluxing is important. It prevents oxidation, absorbs and dissolves residual oxides and assists in the flow of the silver.
The precautions are that you can still buy silver braze with Cadmium in it. The health issues with cadmium are well documented. The flux will often have boric acid in it.
If you're doing a lot of brazing just do it in a well ventilated area.
Can you actually use a propane torch as mentioned in one of the posts?
A propane torch when used in open air can reach a temperature of approx. 3,623 Fahrenheit. MAPP a little higher @ 3,720 F.
The liquidus temperature (when the alloy is completely liquid) and the solidus (the highest temperature at which the alloy is solid) will vary with the alloy content. We use a 45% silver and it has a higher melting point than the 56%, but that is not always the case. It depends upon the manufacturer and what other elements are alloyed with the silver (generally copper and zinc). This range for us is between 1220 F and 1370 F. Harris welding has a very informational website.
My preference is very concentrated heat source (pencil shaped flame) the hottest spot is at the tip of the blue.
I generally prefer to localize the heating
However when I was building my radius rod "doubler" I was doing much larger areas , so heating larger areas
Best suggestion I can make is practice a bit
The stuff is not cheap. Probably $50-60 for a "starter kit" at the welding supply store, but well worth it in my opinion
Yes, you can use propane but I find it's only good when soldering small parts. Too big a heat sink and propane can't quite get it.
Many years ago I bought my "oxyacetylene " torch. I have never regretted owning it!!! Just the other day I was "dismembering " a T chassis. With "judicious " use of heat I was able to save a number of parts I would have destroyed otherwise!!!
I had better correct one thing. Once you have it you will have to learn the difference between friends and freeloaders!!
One will bring beer or at least a coffee from Tim Hortons!!!
The other, well you will learn
Try to take some lessons in the use of it. Well worth the money and time