Silver Solder vs. Loctite Retaining Compound

[JRaut]

Thanks, that helps a bunch.

My drawings call for “Silver soldering” of the joint.

So perhaps I shouldn’t even be trying to braze it in the first place??

I had always just assumed that Silver Soldering = Hard Soldering = Silver Brazing

I guess not!

Time to buy some of that 4ish% silver solder and matching flux that you’re taking about. And switch back to propane.

Anyway, good experience learning how to silver braze. I’ve soldered a million times, so that shouldn’t be an issue at all.

 

[WCraig]

@JRaut Your thread has been very helpful since I have virtually no experience with anything beyond soldering plumbing pipes and electrical connections.

For more experienced people, I'm still a bit confused about brazing. If fluxed and heated properly, will braze wick between close fitting parts and join them? Or does the braze have to build a bead between the two parts?

Also, a local store lists three types of brazing rods -

Copper: "join copper to copper alloys", working temp 1,450 F

Bronze: "general welding purposes for steel, copper and galvanized steel", working temp 1,600 F

Silver: "join carbon and alloy steels", working temp 1,250 F to 1,750 F

Q's -

So the "Copper" rods would mostly be used brass or bronze work?

The description of the "Bronze" rods seems to suggest they are the most versatile. OTOH, everybody in this thread focused on silver. Why is that?

And just to round it out, why would there be a 500 degree F range for the working temp of the silver brazing rods? Different heats needed to work properly with different steels?

Finally, I'm almost afraid to ask but are there similar variants of "soft solder". IE copper, bronze, & silver soft solder?

Craig

 

[Flyinfool]

JRaut, Your thread has been very helpful since I have virtually no experience with anything beyond soldering plumbing pipes and electrical connections.

For more experienced people, I'm still a bit confused about brazing. If fluxed and heated properly, will braze wick between close fitting parts and join them? Or does the braze have to build a bead between the two parts?

The answer is maybe. Different alloys of brazing rods have different viscosity when melted, This will dictate the proper gap to fill. A low viscosity will not fill a large gap and a high viscosity will not flow into a narrow gap.

Also, a local store lists three types of brazing rods -

Copper: "join copper to copper alloys", working temp 1,450 F

Bronze: "general welding purposes for steel, copper and galvanized steel", working temp 1,600 F

Silver: "join carbon and alloy steels", working temp 1,250 F to 1,750 F

Q's -

So the "Copper" rods would mostly be used brass or bronze work?

Yes

The description of the "Bronze" rods seems to suggest they are the most versatile. OTOH, everybody in this thread focused on silver. Why is that?

The bronze will stick to most steels and copper alloys. Most, not all, Silver Brazing alloys have a fairly low viscosity when melted, This means they ar not good at forming a fillet and will use capillary action to flow into a close fitting joint. The bronze it better at making a nice fillet between to parts

And just to round it out, why would there be a 500 degree F range for the working temp of the silver brazing rods? Different heats needed to work properly with different steels?

You would have to look up the specific brand and part no of the one in question, All of the manufacturers have a lot of info on their websites so that you can pick the correct alloy for the fob at hand.

Finally, I'm almost afraid to ask but are there similar variants of "soft solder". IE copper, bronze, & silver soft solder?

Craig

Never be afraid to ask. The only dumb question is one you already know the answer to.

Yes there are many variants of solder, some "soft" and some "hard", with various melting temperatures and viscosity when melted and some for specific metals to be joined. Again the manufactures websites have a lot of into to help you select the best product for your job. In my basement I probably have at least 30 different kinds of solder and braze to pick from.

Yes there are general purpose solders and brazing alloys that will work OK on most things, These are the ones most people start out with and then expand as you run into special cases that need something better for the job than the general stuff.

 

[hman]

I think the "copper" brazing rod is mainly meant for plumbing (copper pipe, brass fittings).

Expanding a bit on the info that @Flyinfool posted, the various melting points for brazing alloys are due to the small differences in the alloys from various suppliers. I'd say that the preference for silver brazing rod is probably due to the lower working temperature.

Soft solders will generally all work for anything solderable.

The traditional solder for electronics is 60/40 (60% tin, 40% lead) and has a flux core. There's a similar alloy called "eutectic," I think 63/37, with a slightly lower melting point. Nowadays, there's a push to eliminate lead, so they're going to various lead free alloys, generally with higher melting points.

There's also (or at least was) an acid core solder, meant for other metals. The acid core is a more aggressive flux, but not really suitable for electronics.

Finally, there's silver-bearing soft solder. Stay-Brite is a very popular brand. It's solid wire (no flux core), so you need a separate flux. Stay-Clean, by the same company, is popular. I've used Stay-Brite/Stay-Clean for years for numerous purposes, and think it's wonderful. Silver bearing solders are lower melting than most others. As with silver brazing alloys, the disadvantage is the higher cost (due to the silver).