Large Scale Central

Silver Solder

I am soldering brass rod. Mostly 1/16" diameter. presently I am using standard rosin core tin/lead solder. Would silver solder be more appropriate ? Is it stronger than common electronic solder ? Where would be a good source ?

Dan, It depends on your application. If you are looking for a bit more strength, you can switch to plumbers solder and still be able to solder at relatively the same temperature. This type of soldering is plenty strong for most things.

Silver soldering is a whole other animal and is a bit more involved. The brass will need to be heated until it is red hot (about 1000 deg.) in order to melt and flow the silver solder. This makes the brass very soft and you will have to quench it to re-harden it. The solder is actually 50% or more silver making it quite pricey. Also you will need special flux to go with it. I am lucky enough to be able to purchase both the solder and flux at a local welding store. One package of solder has lasted my entire ruby bash project with plenty to spare. You use it very sparingly. Here is a link to it that may help answer some more questions.

http://www.largescalecentral.com/forums/topic/22725/ruby-bash-1-20-3-0-4-0-build

Basically I use silver solder for boiler work. It can stand the 300+ degree temps that might start to soften regular solder, and has much more strength to contain the pressure. I also use it in areas that may be close to the boiler heat and soften. For all of the cab work and tender I have just used soft solder and it does fine. A few exceptions are where I will silver solder a big part that I know I’ll be doing a lot of other soldering around. This way I don’t have to worry about melting that doing the other things.

Please let me know if you have any other questions I didn’t cover.

Another item that should be considered is a resistance soldering outfit. They are pricey, but they heat control afforded is far superior to any torch or iron. Both the torch and iron take time to heat the elements, and must be applied to both parts. Resistance soldering applies the heat to both parts simultaneously by creating a short circuit, which generates the heat much faster, and therefor more locally and concentrated. I have a devil of a time with the search engine here, but look up the box cab build by either Jon Radder or Bruce Chandler (I forget which).

And when you get real good, you will be able to brass braze the parts together. I have often wondered why the steamies don’t use steel sheet and brass braze for the boilers in stead of the brass sheet and silver solder. I would think the steel/brass would be better for the boiler…and stronger allowing higher steam pressures.

Bob C.

Terms, please.

The plumbers solder with silver in it is referred to as Silver Bearing solder. 420-460 degrees F melting temps. Home Disappointment carries it.

Jewelry grade Silver Solders have melting points just below pure silver in the 1350 degree F range. Using these solders can result in annealing the metal, which may not be desirable. Use caution relying on shock quenching which can open pinholes. I use a hot pickle to quench and clean off the melted on flux and coatings I apply. Mixing powered boric acid in denatured alcohol to make a paste. Apply and burn off alcohol then using a soft flame melt the boric acid to your metal will prevent most discoloration. Powdered not granular BA is available at pharmacies.

However coating with Battern’s self pickling flux can protect the temper, if you are quick. (http://www.largescalecentral.com/externals/tinymce/plugins/emoticons/img/smiley-wink.gif)The solders I used were 80 -90% silver because I didn’t want visible seams in my silver work. The softer (lower temp) the solder the less silver and more non-silvery metal that can be seen. Solders tend to oxidize faster too.

My present source for supplies:

https://www.riogrande.com/

Silver bearing solders are stronger and much more suited for building than the rosin core electrical solders. Most electrical connections are arranged so that the joint does not support the connection.

Only boilers require Silver Solders for strength more than melting temp.

John

Bob “IA3R#7” Cope said:

Another item that should be considered is a resistance soldering outfit. They are pricey, but they heat control afforded is far superior to any torch or iron. Both the torch and iron take time to heat the elements, and must be applied to both parts. Resistance soldering applies the heat to both parts simultaneously by creating a short circuit, which generates the heat much faster, and therefor more locally and concentrated. I have a devil of a time with the search engine here, but look up the box cab build by either Jon Radder or Bruce Chandler (I forget which).

And when you get real good, you will be able to brass braze the parts together. I have often wondered why the steamies don’t use steel sheet and brass braze for the boilers in stead of the brass sheet and silver solder. I would think the steel/brass would be better for the boiler…and stronger allowing higher steam pressures.

Bob C.

Bruce Chandler did the Box cab. And do our models need to have higher steam pressures. It seems like overkill(http://www.largescalecentral.com/externals/tinymce/plugins/emoticons/img/smiley-cool.gif)

Bob “IA3R#7” Cope said:

Another item that should be considered is a resistance soldering outfit. They are pricey, but they heat control afforded is far superior to any torch or iron. Both the torch and iron take time to heat the elements, and must be applied to both parts. Resistance soldering applies the heat to both parts simultaneously by creating a short circuit, which generates the heat much faster, and therefor more locally and concentrated. I have a devil of a time with the search engine here, but look up the box cab build by either Jon Radder or Bruce Chandler (I forget which).

And when you get real good, you will be able to brass braze the parts together. I have often wondered why the steamies don’t use steel sheet and brass braze for the boilers in stead of the brass sheet and silver solder. I would think the steel/brass would be better for the boiler…and stronger allowing higher steam pressures.

Bob C.

Copper is better at conducting heat, and conducts it more evenly. Also copper will not rust like steel will. Some of the 1:1 locomotives used copper in their boilers, back in the early days. And the hard alloy of copper, can easily withstand the pressures used on scale steam locomotives.

Thanks all. The info was very helpful. I think I’'ll stick with regular solder, but I will try using the plumbers solder I have in my plumbing tool kit.

Dan, I use plumbers solder for mechanical joints, and electrical solder for electrical stuff.