copper soldering 1

[dkm0038]

Can I solder (with a regular butane or propane torch) copper and steel?

if so what kinda of flux and solder material is used.

 

[racookpe1978]

Well, solder joins two mettallic objects by melting the low-temp solder into the joint between the two items: For example, copper-copper pipe-type fittings "wick" the solder into a close-fitting gap between the two. Same with electric connections. Since you aren't melting either the copper nor the steel, the only question becomes joint shape and how the melting solder will "flow" in the gap between the two.

If the mass of steel and copper is too large, no propane torch will heat either enough to melt the solder through the whole joint.

Unlike welding - you can't realistically "buildup" a solder joint if there are even modest sized gaps between the two fittings.

Corrosion going to be a problem? What fluid?

What joint type? Joint shape? Solder strength? - compared to brazing materials, solders are weak.

 

[MiketheEngineer]

I believe steel and copper is mostly a NO-NO. You might get a bit of a joint - but it will not have much strength... Good lcuk...

 

[Adalius]

You'd be much better served brazing the joint if you can.

 

[tomwalz]

You can braze with Propane. It gets hot enough. How much heat you need might be a different thing. See

http://www.carbideprocessors.com/brazing-propane.htm

More info at:

http://www.carbideprocessors.com/brazing.htm

Probably best to use 56% Silver braze alloy and black flux.

Tom


Thomas J. Walz
Carbide Processors, Inc.

http://www.carbideprocessors.com

Good engineering starts with a Grainger Catalog.

 

[berkshire]

dkm0038
If you have to solder steel and copper together, it is advisable to tin the steel first, before attempting to solder the copper to it. A zinc chloride based flux is needed for the steel, and the copper would need to be cleaned with hydrochloric acid, before the addition of zinc chloride. There are some proprietary fluxes like "Stay clean" That contain a small amount of free acid to do this.

http://www.harrisproductsgroup.com/consumables/fluxes.asp

You are better off using a soldering iron, than an open torch, but a torch can be used.You can use tin/lead solder or lead free solder for this. Neutralise afterwards with baking soda.Do not use this flux for electrical work.
B.E.