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HVACR316 - Piping

Soldering

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Soldering Copper Tubing

• The most common method of joining copper tubing in hydronic heating systems is soft soldering using a 95/5 (95% tin/5% antimony) solder.

• The maximum working pressure rating for of 95/5 solder is approximately 300 psi.

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95/5 Solder

The alloy content of all solders are listed in this area.

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95/5 Melting Range

• The melting temperature range for 95/5 solder is 452° – 464°F.

• The narrow melting temperature range of 95/5 also means the joint will solidify very quickly when heat is removed.

• In other words, a fine balance of heating is needed when soldering.

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Proper Soldering Procedure

• Proper soldering results in clean, neat and water-tight joints.

• Sloppy joints, even if water tight, indicate poor craftsmanship.

• With a little practice, making good solder joints will become second nature.

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Soldering

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Soldering: Step by Step Procedure• Step 1. Be sure the tube is cut

square; use a wheel cutter. Avoid using a hack saw whenever possible.

• Step 2. To remove any burrs, ream the end of the tube with the blade of the cutter wheel, a rounded file or another type of de-burring tool.

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Wheel cutter De-burring tool

Wheel Cutter and De-burring Tool

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Soldering: Step by Step Procedure• Step 3. Assemble the joint and

check it for proper fit and alignment.– In most cases, there will be no

problem with the fit. – However, sometimes a fitting may

be damaged or defective.– If the fitting wobbles noticeably on

the pipe, it should be replaced.

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Soldering: Step by Step Procedure• Step 4. Clean the socket of the

fitting with a properly sized fitting brush. – Be sure to remove any pieces of the

steel brush bristles remaining in the fitting after cleaning.

– These small pieces of steel can create galvanic corrosion that could eventually cause a leak in the fitting.

– When cleaning a large number of fittings, a cleaning brush can be adapted to fit in the chuck of a cordless drill.

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Cleaning Brushes

Hand cleaning brush Cleaning brush adapted to fit in a drill

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Soldering: Step by Step Procedure• Step 5. Clean the outside of the

pipe with an emery cloth. – All oxidation, scale, dirt or paint

should be removed from the tubing surface at least ½” inch further back than the edge of the fitting socket.

– The tube should appear bright following cleaning. Be sure to clean all the way around the perimeter of the pipe.

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Cleaning Copper Pipe

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Soldering: Step by Step Procedure• Step 6. Apply paste flux to the

fitting socket and the portion of the pipe that fits inside the socket. – The flux chemically cleans the surface

of the copper and helps prevent oxidation of the surfaces when heat is applied.

– Always use a flux brush, not your fingers, to apply the flux.

– Do not apply excessive amounts of flux. Only a thin film is needed.

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Soldering: Step by Step Procedure• Step 6, cont’d.

– After fluxing, slide the tube into the fitting and, whenever possible, rotate the fitting once or twice to further spread the flux.

– Finally, wipe the excessive flux off with a clean rag prior to applying heat.

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Applying Flux to the Fitting and Pipe

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Soldering: Step by Step Procedure• Step 7. Apply heat to the outside

of the fitting socket using a torch. – Keep the blue tip of the flame just

above the surface of the socket. – Move the tip of the torch around the

fitting to promote even heating.

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Applying Heat to a Fitting

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Soldering: Step by Step Procedure• Heating times differ considerably

with the type of torch and gas being used, as well as the pipe size, ambient temperature and type of solder. – When the flux begins to sizzle or

turn very clear, test the joint by applying the tip of the solder to the edge of the joint.

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Soldering: Step by Step Procedure

– If it sticks but does not melt apply more heat.

– If the solder immediately melts, the joint is ready to draw in the molten solder by capillary action.

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Soldering: step by step procedure

– Once the solder begins to flow, it can be continually fed into the joint. Only a small amount of solder is needed.

– An experienced pipe fitter knows by sight how much solder to feed into a joint.

– An inexperienced person often feeds excessive solder into the joint.

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Soldering: step by step procedure– The excessive solder can solidify

into small loose particles inside the pipe.

– These can be carried around the system by the fast moving fluid and become lodged in valves or circulators.

– A good rule of thumb is to use an approximate length of solder that is equal to the diameter of the pipe.

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Soldering: Step by Step Procedure• Step 8. After the solder is

applied, remove the torch and if necessary, carefully wipe the perimeter of the joint with a clean cloth to remove any excess solder or flux.– The joint should be allowed be

allowed to cool naturally before being handled or stressed.

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Soldering: Step by Step Procedure• Step 8, Cont’d.

− After the joint has cooled, one last wipe of the pipe with a damp rag will remove any remaining flux.

− This is an important step because flux residue left on the joint eventually causes unsightly surface oxidation.

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Soldering: Step by Step Procedure• Be a professional and always clean

every joint.

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Additional Soldering Tips

• Its best to create piping assemblies on a horizontal working surface.– The solder flow is more controllable.

• When soldering has to take place next to a combustible material, place a noncombustible material, such as sheet metal, between the torch and the material you are protecting.

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Additional Soldering Tips

• Measure all tubing carefully before cutting.

• Allow for the amount of pipe that will fit into the fitting socket.

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Additional Soldering Tips

• Whenever possible, attempt to keep all piping plumb (vertically and horizontally).

• Install temporary piping support if necessary to hold the pipe in proper alignment for soldering.

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Additional Soldering Tips

• When soldering valves, open the valve to allow heat to exit, so no valve damage occurs. (This is especially true for zone valves.)

• Always read the installation instructions from the valve manufacturer.

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Additional Soldering Tips

• On fittings that have both soldered and threaded fittings, assemble the soldered joint first.

• This prevents discoloration or burning of Teflon tape or joint compound during soldering.

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Additional Soldering Tips

• Always keep one end of the pipe open when soldering.

• If this is not done, pressure can build up in the pipe due the heat and cause pinholes to form in the solder.

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Additional Soldering Tips

• Finally, take a few extra minutes to clean up excessive flux and solder.

• Your customers will notice it!

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Some More Advice….

• If at first you don’t succeed, then skydiving isn’t for you.