I am a general contractor but it has been years since I sweated copper.
I cut the pipe with a pipe cutter tool. I clean both the pipe end (male) and
the fitting (female) thoroughly. It is shiny clean. I coat both with paste
flux (the brown stuff). I put the two pieces together until the pipe seats
all the way into the fitting. My torch is one of these where you just push
the button and the gas comes on and it lights. The flame is not a pin-point,
it is pretty open. I hold it about an inch from the fitting and heat it up.
I have to stay on one side of the fitting since I am blocked by things in
the way. the flame is on it about 8-10 seconds. I apply solder and it melts
but it doesn't go into the fitting, it just balls up and runs off without
being sucked into the fitting. What am I doing wrong?
I had this problem when using the flux that came with my torch kit. The
flux was white and I couldn't believe it was the problem, but after
several joints did just as you describe, I decided to try different
flux. I bought some Oatey brand which looks a little like grease. It
is brownish in color, but somewhat translucent whereas the white flux
that came with my torch was completely opaque and looked a little like
With the Oatey flux, the solder behaved just as it should and the joint
sucked it in like a sponge. I suspect the flux in the torch may have
been old or a bad batch or something, but it was unlike any other flux
I'd seen before. I guess that alone should have made me suspicious sooner.
So bad flux is one possibility. Also, are you sure you have solid
plumbing solder and not solder with rosin or acid core as used for
Lastly, if you overheat a joint you will burn off the flux and oxidize
the copper and then the solder will behave as you describe. I wouldn't
think 8-10 seconds would do that, but if you have a MAPP torch this is
possible. I wouldn't think propane would overheat that quickly. The
way to avoid this is to hold the flame farther away to give the heat
time to work around the fitting before the flame side gets too hot.
Also, keep touching the solder to the joint every second or two as the
fitting heats up. That way as soon as the solder begins to melt briskly
when touched to the fitting, you know you have enough heat and can
remove the torch and feed 1/2" or so of solder into the joint (for 1/2"
tubing - 3/4" or so for 3/4" tubing).
And definitely remove the torch as you feed the solder as you will have
plenty of heat at that point and don't need any more assuming you are
feeding the solder into the joint at a point roughly opposite where you
are applying the hear.
I was just over at the Depot and looked at fluxes. One was a "tinning flux"
and the other was "regular flux". The regular flux was the translucent brown
stuff and the tinning flux looked like a light green toothpaste.
The brown stuff is what I have been using. The solder is correct, right off
the shelf next to the wire brushes and the flux. I am using propane, not
MAPP gas. I am pretty close to the fitting, maybe just an inch or so. If the
flux burns off, will the solder still work? Most of the instructional videos
I see for sweating copper, the flame tip comes to a point. My flame tip is
pretty broad. Maybe that is better in that it heats the entire area, not
just at the flame tip. Any thoughts?
I'm not a professional plumber, but I did add a bathroom to my basement
last year and got to sweat a fair number of joints and also had to "T"
into my main 3/4" home lines (that was a little nerve racking). I did a
few practice joints and once I got the right flux it worked well.
Yes, you can definitely burn off the flux and, no, the solder won't take
when that happens. If you start to see a lot of smoke, you are too hot.
Again, an experienced plumber can tell when the temp is right simply
by the time taken and watching the flux begin to bubble and the copper
change color. Amateurs like us should use the technique of continually
(every 1-2 seconds) touching the solder to the joint. It will first
start to "stick" a little to the fitting and that tells you that you are
ALMOST up to temp. Probably a touch or two later will cause the solder
to almost instantly melt when you touch the joint and that is when you
want to IMMEDIATELY remove the torch and then promptly feed in enough
solder to form a small partial droplet on the low part of the joint.
Wipe quickly with a damp (not wet as you don't want to shock cool the
joint!) rag and you are done.
Not a lot of difference unless you're talking of really large diameter pipe.
The thing sounds to me is you're not heating the fittings hot enough --
as someone else says, you've got to heat the fittings enough to melt the
solder, not using the flame to do so.
If you haven't soldered for a while, go get a few practice fittings and
practice until you get the hang of it.
Heat the fitting (not the pipe into the fitting) at the base of the
fitting from the rear and touch the solder to the joint on the near
side. When it gets hot enough, it will melt and flow in w/ capillary
OH? do tell...... and lets not cite that government bullshit about lead
leaching into the water and getting consumed.. doesn't hold up... millions
of us grew up drinking tap water from real solder sweated copper plumbed
On Mon, 20 Oct 2008 19:25:15 -0500, "Steve Barker DLT"
Agreed, I too grew up in houses with lead soldered pipes. I don't
think it caused my Drain Bamage, but can't be sure. <bg>
The issue is that later, when selling the house, if the buyer finds
lead solder in a house where there should not be any, the seller may
(well after the fact, too) be required to set it straight. Selling a
property in today's world is very complex, and leaves the seller
holding the bag, so to speak, for extended periods of time.
Since it wasn't until the 1980's that lead free began to be
required .....there are a whole lot of homes in the US with lead based
Lead paint was phased out in the 70's.
So what % of US homes have some lead paint & lead based solder?
yeah, lead free solder might be a good idea but I'd like to see the
data showing how much personal lead loading is due to residential use
of lead based solder.....
fyi only 50% of ingested lead is absorbed...90% of inhaled lead is
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