soldering giving me problems ...

[tbb2]

I've soldered a few small jobs in the past but now am having problems.

I feel I am missing something basic that did not come into play on my previous work.
I'm assembling 3/4 and 1/2 copper supply pipes for a new bathroom.

Maybe someone can clarify and/or answer some of these questions:

1) I suspect the problem has something to do with even heating of the pipe.
- Is there an optimal distance to hold the torch (propane) off the pipe and joint?
- I am heating the pipe first and then the joint. Is it the reverse? Does it matter?
- There seems to be a small window of time that the pipe is hot enough to melt the solder but I still get solder running around a horizontal joint and dripping out the bottom without being carried into the joint (I'm only using a thin coat of flux).

2) I am trying to assemble the major sections of pipe on a sheet of plywood. This helps keep a long assembly of pipe with angles square.
- Should I be putting something under the pipe to separate it from the wood?

3) If I have several joints in close proximity should I place and solder each one separately or assemble the group and move from one to the next?

4) My understanding is that the soldering process works by heating the pipe so it melts the solder and once liquified it is draw by capillary action into the joint.
- Is there something else going on?

Yes ... I'm feeling like a beginner.

Thank you.

[Tom Sawyer]

Clean clean and clean some more. Inside the fitting, outside the pipe. Ream the inside of the pipe. Flux outside the pipe and inside the fitting. A light coat, not a snot ball. Assemble the joint. Heat the fitting not the pipe. when flux bubbles apply solder to the joint. 1/2" fittings need a 1/2" of solder, 3/4 -3/4 and so on until you get to 1-1/4" and larger which take more solder. Let cool naturally. Wipe the excess flux off the joint. If the fitting turns black when heating it's too hot. Disassemble it, re-clean it and start over.

[Hairyhosebib]

Heat the pipe too. It is as much of the sweat joint as the fitting is. This is very important when sweating larger copper pipe assemblies. I was trained to move the torch in a figure 8 pattern from fitting to pipe for even heating.

[jadnashua]

The fitting is the heavier (usually) component, so normally, if you heat it, when it's hot enough (since it's in contact with the pipe), the pipe will be hot enough as well.

[Tom Sawyer]

Never heat the pipe. Size the flame to the size of the work and there is no need to heat the pipe or use a figure 8 pattern. Apply the flame to the center of the fitting and move it to where the flame wraps around the fitting.

[Terry]

Laying the pipe on plywood and soldering it there is a mistake.
If you want to "prefab" the pipe, at least block it off the ground. Heating the fitting and pipe evenly is very important. That means getting heat to all sides of the fitting.

[Hairyhosebib]

Never heat the pipe. Size the flame to the size of the work and there is no need to heat the pipe or use a figure 8 pattern. Apply the flame to the center of the fitting and move it to where the flame wraps around the fitting.

If I'm working with 4" copper, where will I get a torch that big?

[bluebinky]

If I'm working with 4" copper, where will I get a torch that big?

You can afford 4" copper?

Obviously, what works at one scale doesn't necessarily work at another...

[Hairyhosebib]

I work at a university. Occasionally we work on water mains and sump pump piping.

[jimbo]

If you are working 1" and less, then heating the fitting usually is adequate to also bring the pipe up to temp. Nothing wrong with briefly hitting the pipe with the flame. On the flame, there is an inner, very bright blue area. The end of that bright blue is the hottest part of the flame.

A pipe of say 3/4" size should be at temp in less than a minute. If you are heating longer , then you may burn the flux.

[Hackneyplumbing]

Do not direct your flame into the face of the fitting. Do not burn your flux...(over heating)

[Tom Sawyer]

4" copper, it's time to get out either the Turbo T8 tip or go with acetylene.

[WorthFlorida]

You mentioned your using 1/2 and 3/4 then later on 4" pipe? if your using 4" copper waste lines then you'll need an acetylene torch for the 4". Copper is the second best conductor of electricity and one of the best conductors of heat. If it is the 4" pipe giving you problems it is because a propane cannot heat such a large area and you may get cold solder joints (leaks). On a 1/2 and 3/4 pipe your leaving the torch on the pipe too long and over heating it thereby allowing the solder to remain a liquid and run out if the joint.

How to solder a joint, as mention earlier is clean copper at all joints. You must use flux on all joints and a just smear is good enough. What flux does as it is heated it actually cleans the copper and prevents the copper from oxidizing, therefore do not over heat the joint, Solder travels from cold to hot, as the pipe gets to temp apply the solder furthest from the flame but the flame should be removed almost immediately. Once you see the bead of solder to go around the pipe pull the solder & heat away.

When soldering on a vertical section of pipe, always start at the lowest connections. Heat also travel up the pipe faster than it travels down. If you start at the top and work down, the heat will rise and kept the connection soft and the solder may run out of the joint above.

For info on solder go to http://en.wikipedia.org/wiki/Solder

[Hairyhosebib]

http://www.copper.org/

I personally don't have a problem with copper but this might be of some help. There are some videos here. They have a training program, they will come to you and do a hands on seminar. Not sure if it costs anything. There is a product called COOL GEL. It is a great aid for doing this kind of work too.

http://www.laco.com/productDetail15.aspx

You can spray this stuff on cardboard and put a turbo torch to it with mapp gas and it won't burn. AWESOME PRODUCT. ACE sells something similar.

[hj]

quote; Heat the pipe too

The solder flows TO the hottest area of the joint so you heat the fitting where the end of the pipe is. As for 4" copper, you borrow my 4 burner staghorn acetylene tip, (I also have a smaller one for 2" copper).