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Soldering copper pipe without fittings?


#1

First, let me appologize. I know this is a jewelry list, and I am
asking a non-jewelry question, but you guys seem like the most likely
place for me to find an answer. I have searched the web until I am
too tired (almost) to continue and have as of yet found no answers. I
am currently nurturing my artistic side and want to make a garden
trellis or two and arbor out of common copper plumbers pipe (1/2",
3/4" and 1"), but I don’t like the look of the fittings. I am needing
90 deg and 45 deg joints as well as tees. Also, I’d like to make my
little girl some outdoor furnature…a table and chairs that will
need the same type joints. I have had success cutting the pieces in
the appropriate angles, but do not know how to join them. I currently
do not weld, so I was hoping I could solder the joints and they’d be
strong enough??? I’ve done some jewelry making in the past and
soldered copper for that with good success. I’ve read all the
threads on copper here, but have not found any directions for making
these type of joints. Any help here would be greatly appreciated. My
sincerest thanks in advance, Sarah


#2

Sarah, I really think you will be safest and maintain your sanity if
you go with fittings. Butt soldering, even with silver solder
(harder and stronger but needs much more heat than lead solder) and
even if you did weld (TIG) the butt welded joints, I don’t think,
are near strong enough for your purposes. Try TchTalk at
http://www.ArtMetal.com and see what that list comes up with.
Copper pipe is soft thus weak at best, butt weld just really equal
"weak" structure.

John Dach


#3

Sarah, I love the sound of your project.

My first thought is “Do you know any plumbers?” I think you will
have to use a plumber’s torch and solder. Clean the joints, fit them
together, stabilize or secure them with wire so they don’t move
around while you’re soldering, slather with flux, then fire up the
torch and feed the solder into the joint. If it’s lumpy or has an
unattractive texture, you can always smooth it out with a file or
sandpaper.

You’ll probably get many more detailed answers from the more
knowledgable on the list.

I’m looking forward to everyone else’s responses.

Christine in Littleton, Massachusetts


#4
and want to make a garden trellis or two and arbor out of common
copper plumbers pipe (1/2", 

Hi Sarah, A great book for your projects would be Black & Decker’s
"Building Garden Ornaments" ISBN#0-86573-590-5

Have fun! Marta Irvin


#5

I want to make a garden
trellis or two and darbor out of common copper plumbers pipe
(1/2", 3/4" and 1"), but I don’t like the look of the fittings. I
am needing 90 deg and 45 deg joints as well as tees.

G’day’; I believe you have two options, both of which will require
you to make a visit to your local welding supply shop. You can’t
really actually weld copper without special equipment and
experience.

1); Brazing. This is done using filler rod of a special brass
and is available in several thicknesses, but I suggest that 1/16th"
rod/.wire is what you need. You also need a flux. Now borax will
do, but the fluxes that are commercially available for brazing are
better. Copper is notorious for oxidizing on the surface when
strongly heated, and a good flux will dissolve the oxide as it is
formed and will keep the surfaces clean to obtain a good flow and a
strong joint. You will need a good torch with a very hot flame,
and I recommend oxygen/propane, though many plumbers use an
air/acetylene torch. Copper is a good conductor of heat; almost as
good as silver, so that is why a really good hot torch is
necessary. The pieces to be joined must be held together in some
manner (I use a chemistry ‘retort’ stand and clamps) but they
don’t need to be the perfect fit that silver solder demands; brazing
rod is a gap filling material, and part of it’s strength is obtained
by the joint having a build up of ‘fillet’ metal. The brazing rod is
applied as necessary to achieve a good joint, as in lead soldering.
The rod is heated then dipped into the particles of solid flux which
will adhere to the hot rod before being applied to the job. The
technique is not difficult, but a little practice will be necessary
for a newcomer to brazing. The metal needs to flow to a liquid, so
a technique of being able to control work temperature by moving the
torch about as necessary will soon be acquired with practice. Wish
I could show you! The main ‘secret’ is getting the job hot enough,
clean enough and keeping it hot enough for the metal to flow
easily, but only where it is wanted. Brazed joints are very strong,
but there is one small problem; to get the joint hot enough to do
the job will soften and anneal the copper at that point. When the
joint is completed, hot water and a stiff brush will get rid of
remaining flux. It may also be pickled in sodium bisulphate pickle
as used in silver soldering, to remove oxide. You will need to
braze a disc to the end of the pipes, but drill a tiny hole in the
pipe to let out expanded air and steam. I have made large aquariums
by brazing together a rectangular frame of angle iron , and they
seemed almost as good as welded ones for that purpose.

  1. ‘Silphos’ This an alloy rod containing a little silver, brass,
    and phosphorus which is applied to the joint as in brazing, except
    that it does not need quite such a high temperature, but almost so.
    Plumbers use this all the time in New Zealand when plumbing a house
    with copper pipes, but it isn’t as strong as brazing. It doesn’t
    need to be, as house plumbing doesn’t suffer the stresses that your
    furniture would. This material is also gap filling, but a
    negative thing about it is that the joint appears a dark, dirty
    grey. This doesn’t matter with plumbing as the pipes are usually
    hidden. Incidentally, modern houses are plumbed with black heavy duty
    polythene piping; copper has gone out of fashion.

For cutting the copper tubes, I suggest you get a cheap mitre box
from your local DIY store, and use a 'G" clamp to hold the pipe in
place whilst cutting with a fairly fine toothed hacksaw. Remember,
as with jewellers saws, at least two teeth must always be in contact
with the metal. Use a bit of candle as a lubricant on the saw.
If you need to file the copper, give the file a squirt of WD 40 or
CRC555 to stop it clogging. Even kerosene will work.

Please let us know how you get on.

Cheers for now,
John Burgess; @John_Burgess2 of Mapua, Nelson NZ


#6

http://www.handyharmancanada.com/TheBrazingBook/bbook.htm

Unfortunately your desire to join copper tubing with butt joints is
not very sound.

Copper is rather difficult to actually weld as is silver. As a
result they are usually joined by “brazing” which is joining with
a metal that melts at a lower temperature than the base metal.
This is often called silver “soldering” since alloys containing
silver are commonly used. “Soldering” is not really the correct
term for this since the term really applies to joining using
filler metals melting below 850 F ( 454 C) . The term
generally accepted for filler metals melting above this temperature
is “brazing”.

Butt brazing joints ( as you are wanting) are not very acceptable
because they are not very strong. As a result lap joints are used.
Copper fittings are designed for the use of “soft” solders that
are “solder” by definition and melt below 850 F. These are
generally lead or antimony based with tin being the minor
component. Fitting are designed with the joint clearance and lap
width to safely work with these “Solders” . These fitting are also
used for " Brazed joints using higher temperature filler metals, a
primary example being hospital oxygen piping systems.

Another problem with copper is that there are no good color
matching brazing alloys for copper. A material that is sometimes
used for jewelry work is old US one cent pieces. This alloy (
95% copper - 5% zinc) is also a called gilding metal. It works
but melts very close to the base copper metal. it is not sold as a
brazing alloy and is not commonly found in the US.

Copper softens (anneals) during brazing and the joint can bend
easily.

To end this on a decent note —for everything on copper tubing see:

http://www.copper.org/tubehdbk/book.html

and only because it is a neat site:

http://bubl.ac.uk/link/a/archaeometallurgy.htm

Jesse


#7

With all due respects to Christine, I don’t think that using the low
temp. solder that plumbers use will hold up to the stress of Sarah’s
project. You really need to use a harder silver solder and be aware
of the inherent problems in silver soldering copper that have been
discussed in previous post on soldering copper. Use a generous amount
of Prips flux and a large bushy flame. You need a lot of heat to
quickly bring the metal to temperature before the metal surface
begins to oxidize. A medium silver solder will give you a strong
joint but the pieces must fit together tightly, no gaps.

Joel Schwalb
@Joel_Schwalb
www.schwalbstudio.com


#8

Hi Sarah,

   am currently nurturing my artistic side and want to make a
garden trellis or two and arbor out of common copper plumbers pipe
(1/2", 3/4" and 1"), but I don't like the look of the fittings. I
am needing 90 deg and 45 deg joints as well as tees. Also, I'd like
to make my little girl some outdoor furnature...a table and chairs
that will 

Copper pipe on its own has very little strength and trying to solder
joints ‘end to end’ without any form of strengthening is doomed to
failure. I would suggest that you look for ‘End Feed Fittings’ at
your local plumbers supply and use these. They are simple formed tube
shapes which slip over the copper pipe and you apply soft solder to
the end of the fitting where it fills the joint by capillary action.
They do not have the unsightly bumps of solder ring fittings or the
chunky uglyness of compression fittings. So, whilst there will be a
visible joint at the corners, it will only be a short plain sleeve as
thick as the wall thickness of the tube. When you use these you MUST
make sure that your pipe and the inside of the fitting are very
clean, preferably by scouring them with a scotchbrite pad.

Best wishes,
Ian
Ian W. Wright
Sheffield, UK


#9

Well this may not help you, if you have already cut the pipe, but
how about making connectors like the tinker-toys(TM?) use? two disks
with half-round relief slots let into one surface, then bolted
together through the center to clamp the pipe ends in place?
whimsical in the garden and appropriate for children’s furniture?
just a passing thought, your intent may vary… Betsy


#10

I just saw this and don’t know what has been said. If you want to
solder copper pipe without using fittings, you need to get a
swedging tool. This tool looks somewhat like a tapered mandrel, and
is inserted into the tube opening. struck with a hammer, and simply
pulled out when finished. The result is a streched opening large
enough to insert tubing of the same size , and then solder. 3/4
into 3/4 1/2 into 1/2. I grew up in heating business. The swedge
came in handy if I ran out of couplings. I hope this helps. Regards,
David


#11

hi, if you don’t mind curves instead of sharp corners you can use
pre annealed copper tube. it’s available at any plumbing supply
house (read not home depot or lowes) . its pricey about $1.00 dollar
per foot and has to be bought in a fairly large coil - 50’ plus. as
far as intersecting joints you can drill holes in 3/4" to fit 1/2"
and solder the joints with easy flo silver solder. the seams can be
furthur hidden by copper plating but i don’t really think that
garden trellises need to be finished as much as fine jewelery as
they are by nature covered up with the plantings. also if you do
really sharp curves fill the tube with sand first to help maintain
your round copper form . hope this helps p.s. most jeweler torches of
the larger variety work fine on copper tube . just use a big
reducing flame

Talk to you later Dave Otto


#12

Another thought I have is to make or find straight fittings that
will make a tight fit on the INSIDE of the pipe where fittings are
needed then use a sweat solder connection (lower heat and less
softening) and a much stronger joint.

I would definitely nix the use of copper tubing, it is W A Y too
soft for this type of structural use. Even with pipe, I would tend
to go with a much larger diameter pipe in copper than in steel (I
would have to look up some specifications but I would imagine 2" or
3" copper would become my minimum choice.

John Dach


#13

Sarah, I’ll go with John Burgess’ advice. Just want to add – use
lots of brazing rod material so it sort of flow/drips out of and
around your joins. If it is lumpy or has texture, I think it would
give an artsy look to your project. In my opinion, the gold/red
(brass/copper) color contrast will look very nice. When it all
starts to corrode, you should still have interesting colors
appearing. Brazing does take LOTS of heat, though, as John said.
Good luck – Judy Bjorkman


#14

I think I have a solution. Swedge the end down of one piece of pipe
so it slips into the inside of another pipe. Try to make it so the
gap = between the full sized pipe end, and the original size of the
pipe at the top of the swedged portion fit close as possible. Then
solder or braze . I know plumbers have the tools to reduce the
end of pipes without causing damage to the pipe, you might try
asking one to help you out. If I figure this right it should give
you the look being smooth with not bulky joint fittings, and give
you more than enough strength.

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Daniel