Soldering Brass/Steel


New member
I've been trying to figure out how to solder brass to steel and I'm not having much luck.

I'm using a butane torch, silver solder and some flux originally intended for copper pipe. I've also tried some electronics flux and 60/40 solder.

The problem I'm having is the solder won't flow into the joint. EG: attempted to solder a set screw into the end of a piece of brass tube, solder would ball up outside the tube, on the screw and wouldn't flow in. Tried varying levels of heat, including getting the tube so hot it collapsed. I don't have this issue with other materials.

Any pointers or tutorials? Should I be using a solder paste instead?


not sure it is possible to solder 2 diff kinds of metal together. however if you are using actual silver solder it needs a very specific flux paste. the stuff I use is from a company called harris. I use the 45% silver solder on metal and 15% on brass.both use a different type of flux. the brass can be done with a soldering iron or butane torch, the 45% needs a lot hotter flame map gas or acetylene. to get steel hot enough for solder to stick the brass or copper is destroyed long before.

this is the products I use. mostly because they are easy to find.


New member
I've seen all kinds joined, even just running propane. Must be something really specific. I'll keep on trying until I get it done.


New member
Brazing won't work without FLUX. Trust me. I tried without and tried with general piping flux and neither works.
Get some of the Sta-Silv Flux and you'll see a massive difference.



New member
I slapped a few pieces together last night using the solder paste. Much closer to soldering than proper brazing. You hit the piece with heat for 3-5 seconds and it's done. Brass/brass, brass/copper was easy. Brass to steel/stainless steel is trickier. I used some fairly aggressive flux to get the steel into the mood, but the joints are weak.

In any case. I fabbed up a set of sliders and made mounting tabs out of brass flat stock. They seem pretty strong, but I miscalculated a little. They're sitting a little too low. It was a good first try in any case..