Nearly ivisible joint for splicing primary copper tubing

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "Scott Hanson by way of Terry Fritz <teslalist-at-qwest-dot-net>" <huil888-at-surfside-dot-net>

A spliced joint in 1/4" or 3/8" copper tubing can be easily made that is
literally almost invisible, and doesn't affect the bend radius of the
primary. If modern non-lead plumbing solder is used (almost 100% tin), the
joint will be stronger than if lead-based solder is used, but this is really
not necessary as this is a non-structural joint.

1. First, ream the ID of the ends of the pieces of tubing to remove the burr
left by the tubing cutter. Just remove the burr, don't bore out the actual
ID of the tubing. A long, thin tapered chassis reamer works great.

2. Next, use a fine file to square up the ends of the tubing. Depending how
carefully this is done, the finished joint can be almost invisible. The ends
of the tubing must butt together squarely without any gap.

3. Find a copper or brass conductor (brass rod, brass screw shank, heavy
solid copper wire, or heavy stranded copper wire) that is a slight
interference fit, or at least a close slip fit in the ID of the tubing.
Because the actual ID of refrigeration tubing varies from manufacturer to
manufacturer, you will have to select a conductor that gives the optimum fit
in your particular tubing. Actually, stranded wire may be easiest as you can
add or subtract individual wires to get the best fit. A tight fit will
ensure that the two pieces of tubing will be perfectly aligned after they
are soldered.

4. Cut the conductor to be about 1" long for 1/4" tubing, and about 1 1/2"
long for 3/8" tubing.

5. Apply non-corrosive flux to the ID of the tubing ends and the OD of the
conductor.

6. Insert the conductor half-way into the end of one of the pieces of
tubing, and work the other piece of tubing over the projecting end of the
conductor.

7. Gently heat both ends of the tubing using a propane torch, allowing the
flux to melt and penetrate the joint. Every few seconds, touch the end of
the solder to the joint to determine when the metal is just hot enough to
melt the solder. DO NOT heat the metal red hot, this will only oxidize the
surface and make it unsolderable.

8. As soon as the tubing is hot enough to melt the solder, remove the flame
and flow solder into the joint. Capillary action will pull the liquid solder
into the joint. If there is any separation of the joint, push the ends of
tubing back together. The heat in the metal will keep the solder liquid for
some time, so do not disturb the joint until the solder has cooled.

9. Wash off any flux residue, and use a fine file to remove any excess
solder on the OD of the tubing. Finally, finish the joint with 400 grit
wet-or-dry abrasive paper. If the tubing was prepped carefully, the solder
line will be as thin as a piece of paper and almost invisible.

Regards,
Scott Hanson




----- Original Message -----
From: "Tesla list" <tesla-at-pupman-dot-com>
To: <tesla-at-pupman-dot-com>
Sent: Wednesday, February 05, 2003 6:59 AM
Subject: Splicing Primary Copper Tubing


 > Original poster: "Mccauley, Daniel H by way of Terry Fritz
<teslalist-at-qwest-dot-net>" <daniel.h.mccauley-at-lmco-dot-com>
 >
 >
 > My primary tubing is a bit short (only comes in 100ft lengths), and I need
 > to splice on a few more turns with additiona.
 > tubing.  Not being a plumber, I have no clue how to splice copper tubing?
 >
 > Anyone have a brief description how this is done?  I guess its done with a
 > blowtorch, plumber's solder, and some flux.
 >
 > Any help appreciated.
 >
 > Thanks
 >
 > Dan
 >
 >
 > ---
 > [This E-mail scanned for viruses by SURFSIDE INTERNET]
 >
 >

---
[This E-mail scanned for viruses by SURFSIDE INTERNET]