The Home Machinist!

I have a question regarding the appropriate solder for use on piping (steam or water) out side of the boiler, can regular plumbers solder be used or does it have to be silver solder?
Thanks, John

I only use silver solder (easy flow 45 ) on all my plumbing on my steamers. soft solder (lead base) just will not hold up when it comes to tightening fittings on the end of lines ,or when you hit a line or bend a line during moving the engine.
Joe

What exactly are you soldering, as far as materials and size?
I would lean towards silver solder personally.

If it sees steam, use silver solder
If it sees water use soft solder

My .02 cents worth

JOHN B

I'd use silver solder...dad didn't on Caribou I, and I've had to re-attach bits on more than one occasion. Kind of a pain on the track, to pull out the blowtorch and soft solder bits back together to get water into the boiler !

The cost of the amount of silver solder for fittings is going to be basically 0 in comparison to the brass involved, or the time...

James

Hi Joe! Glad to hear from you.

I'm re-piping my 1" Atlantic, 3/16" and 1/4" copper tubing is the size and material involved. I'm wrestling with all threaded connections, or a combination of threaded and soldered connections, brass fittings regardless of method.

Joe, silver soldering discouraged me from completing the Raritan, I burned up more parts than I finished. Hence, I'm reluctant to silver solder unless I have no other choice. That being said, I also find that the threads I cut in the copper tubing are weak and tend to break along the helix of the thread. I'm trying to settle on the best method to pipe the engine that will be secure and serviceable.

John

I also recommend silver solder. The problems with soft solder, besides not holding up to the heat of steam, is that the mechanical strength is much lower and the joint is more likely to be be broken, and that once a joint has been soft soldered, it is nearly impossible to clean off so that it can be silver soldered. I usually have no trouble getting a good joint with silver solder. The key is clean metal, plenty of heat but not too high a temperature. I get good results with air/propane or air/acetylene. I flux the joint, heat to a dull red/orange before putting the solder on. Then it melts and pulls into the joint.

Looks like it's going to be silver solder, thanks and Happy New Year to you all. John

jscarmozza wrote:Hi Joe! Glad to hear from you.

I'm re-piping my 1" Atlantic, 3/16" and 1/4" copper tubing is the size and material involved. I'm wrestling with all threaded connections, or a combination of threaded and soldered connections, brass fittings regardless of method.

Joe, silver soldering discouraged me from completing the Raritan, I burned up more parts than I finished. Hence, I'm reluctant to silver solder unless I have no other choice. That being said, I also find that the threads I cut in the copper tubing are weak and tend to break along the helix of the thread. I'm trying to settle on the best method to pipe the engine that will be secure and serviceable.

John

John:
Use the black flux and the cadmium alloy solder which you can get from McMaster. With common sense the cad will not be a problem. This stuff flows better than the cad free. Then set the parts on a 1/8-inch thick piece of steel and heat the steel from the underside, letting the workpiece soak up the heat. Be patient. Don't play the flame directly on the solder. (Contrary to common advice, I use an O/A torch with a long feather on the flame.) A tiny bit of solder placed on the part before heating will then suddenly melt and get sucked into the joint. As to threads, use a 40 t.p.i., which should leave more wall thickness than coarser threads. Since you're soldering the joints, you don't need the tapered threads. You can get 40 t.p.i. taps and dies in almost any size you can imagine at a reasonable cost from Victor Machinery in New York.

Greg's way is one way, the other way is a reasonably appropriate sized propane torch. I find I can do 3/16 _tubing_ with a Turbo Torch burning propane, but anything bigger than that (1/4" tube) needs more heat than that. O/A has the disadvantage of being hot enough to make brass go away, propane is enough colder that it is hard (but not impossible) to wash away brass. Next bit I would add is use some refractory (firebrick) as a hearth to work in, if you can. It will make the work easier. Also, work in subdued natural light- I haven't tried LED's, but flourescent lights are not condusive to seeing the heat of the work. I generally did the work downstairs at dad's, or in the shed, because that was the easiest way to see what was happening. You do need ventilation, the fumes are not something you want to breath deliberately, but as John said ^, it's not going to kill you in 1 small breath either. I didn't use indirect heat, but it sounds like a sensible enough way if you are using O/A.

James Powell wrote:...
O/A has the disadvantage of being hot enough to make brass go away, propane is enough colder that it is hard (but not impossible) to wash away brass. ...

O/A works for me because I use it indirectly and I go slow, letting the parts come up just to the temp needed to melt the solder, and then pulling the torch back as soon as the solder melts. The black flux works well with this extended heating time. I use O/A because it's convenient for me, but it does take practice. And somehow the propane always runs out at an inconvenient time!

Although I did some parts that were about the size of a Hostess Twinkie and I used a propane weed burner for those. (Hmmm... I wonder what would happen if I took the weed burner to a Twinkie....)

Practice with the brass strips like Kozo suggests in the first Shay book. You can do it!