Silver Soldering Leaf Springs

[daves1459]

The silver solder you want is "Easyflo-45". It is available at all welding shops and you can probably find a troy ounce on Ebay. Easyflo-45 has the lowest melting temperature of all of the readily available silver solders at 1130 degrees F plus high fluidity and joint penetration. It has cadmium in it so have ventilation and don't breath the fumes.

The modulus of elasticity of carbon steel is 30,000,000 for all alloys regardless of hardness. That means the spring rate is the same for all steel parts of the same section regardless of hardness. What hardness does is increase the yield strength and wear resistance. But, wear is generally not a factor with springs. Hardened and tempered spring steel will usually have a hardness in the Rockwell "C" scale of 50 to 55 which means a high yield strength. Which means it can be bent a lot and will return or "spring" back to it's original shape. Where as the same spring steel not heat treated will deflect the same amount for the same load but will stay bent, I. E.: not spring back, at a much lower load.

For an elliptical spring like the example of this thread the longest leaf is called the "main leaf" and considered an attachment devise and lot a load carrier. To back up the main leaf usually two leaves of the same length under it are used to carry the load just like in the example. So you'll be fine for your model.

Dave

[gwrdriver]

All good advice, but to elaborate on an earlier post, "roughing-up" is a good start but may not get the job done. Like everything else you've ever read about soldering (of any type) the work must be as clean as possible of contaminates (like oxides), and blueing is an oxide, so removing every trace of blue in the area you want solder to stay, and want or need a fillet, is a must. I usually file it off, to insure I'm soldering to base metal.

[michaellynn2]

Wow, all the good advice. Let me explain the process I used that has lasted for thirty years to be more "clear". I cut and punched my springs. On my top spring I roughed it up. When I roughed it up all the blueing was "GONE" in the joint area and I had a clean metal to use my 45% silver soldier. I cleaned the spring of all the oils. I applied a flux and was ready. When the joint was good and evenly to temp the silver flowed into the joint. To be "clear", I heated from under the area to be soldiered. I did not put the flame on the area to be silver soldiered. The spring area no longer had any SPRING after the soldering to it, but there is three springs of equal length under this top spring to do the job. All of this is on a LE Pacific. I hope this clears up my earlier post.