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Same old, same old

Soldering basics still apply to lead free pipe, valves and fittings.


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May 1, 2015 by STEVE GOLDIE

Soldering is one of the essential skills a good plumber needs to master and it is one of the things I really enjoyed doing in the years I spent on the tools. As a child I was fascinated by the “B” tank my father had as part of his tool kit. I was probably only 11 or 12 years old when he first taught me how to use it. He employed my new found skills to reclaim fittings from the scrap copper he would bring home from jobsites.

Years later, while apprenticing under my father, I remember how satisfied I felt when he finally had enough faith in my abilities to allow me to take the torch and solder all the joints on my own. Soldering a good clean joint with no leaks was something I always took pride in. When I started reading and hearing that the new lead free brass fittings were proving difficult to solder successfully, I was curious and decided to have a closer look.

WHY HAS THIS BECOME AN ISSUE?

Stricter safe drinking water legislation in both Canada and the U.S. led to an update of standards ASME A112.18.1-2012/CSA B125.1-12 and CSA B125.3-12. The allowable content of lead in fittings used in potable water systems was reduced from eight per cent to a weighted average of less than 0.25 per cent. This is why we are seeing lead free versions of everything from bronze pump bodies, to backflow preventers and all the brass fittings and such. This dramatic reduction in allowable lead content affects the chemical composition of the brasses and bronze alloys that are widely used in our industry.

When I started researching this article I did find quite a lot of chatter on some of the industry online chat forums regarding this issue. Some people were indeed finding the new fittings difficult or even impossible to solder without leaks. Many theories were floated. Some blamed overheating or overly aggressive cleaning of the joints with wire brushes, while others seemed to believe that the flux was the culprit.

Flux manufacturers are capitalizing on this with the introduction of specialty “tinning” fluxes designed to make soldering these new components easier. The question is, are new materials and methods really necessary?

I asked local plumbers if they had experienced any issues. The majority had not, although some did say the new fittings seemed to take longer to heat up. With no clear consensus emerging, I decided I had better take things into my own hands. I dusted off the old tools, grabbed a few of the new lead free fittings and some pipe, ranging from ¾ in. to 1 ¼ in. in diameter and headed off to my garage to play.

Now keep in mind it has been almost 14 years since I laid the tools down to cross over to the “dark side” and work in wholesale, but I am happy to say I still have it. The lessons my dad gave me in this same garage more than 40 years ago seem to have stuck. I had no problem whatsoever in soldering the new valves and fittings, even the ones using an old tub of solder paste that has been in that garage since I quit.

The only detail I noticed was that the newer fittings do indeed take a little bit longer to heat up. This is a result of the lower lead content, which does reduce the thermal conductivity somewhat. This could lead some installers to use larger tips and possibly overheat the joints causing some of the issues of failure.

My conclusion is that the newer lead free fittings may be a bit less forgiving of what I will call operator error; they do not require any special products or methods. As long as good practice is followed: pipe and fittings are properly cleaned, the flux is properly applied and the joint is thoroughly and evenly heated, then solder is going to flow as it always has and successful joints are easily achievable. In other words, the way my dad taught me many years ago still works. Clean both the pipe and fitting and avoid touching it once it has been cleaned, apply heat to the pipe first before moving onto and around the fitting to evenly heat the joint and avoid concentrating the flame at one spot and letting the entire assembly heat up from there, as this can cause overheating in spots which can burn out the flux resulting in inferior and possibly leaky connections.

The only other detail I noticed in researching this is that as a result of the different composition, some of the newer fittings do oxidize faster than the old ones. Therefore, it is best to clean immediately before assembly and soldering. Some issues may occur if fittings are cleaned in bulk hours or even days before they are actually assembled and soldered.

If you have experienced any issues in soldering the new lead free components, it is probably a good idea to have a closer review of ASTM B828, which has been the standard for more than 50 years (see bleow). It is tried and true and it will continue to be the standard as long as we are using copper and brass in plumbing systems.  <>

Steve Goldie learned his trade from his father while working as plumber in the family business. After 21 years in the field, he joined the wholesale side of the business in 2002. His expertise is frequently called on to troubleshoot systems and advise contractors. He can be reached at sgoldie@nextsupply.ca. See Steve at Modern Hydronics – Summit 2015 in Mississauga, ON, on September 10.

Tried and true soldering
ASTM International has written the standard for good soldering practice. That standard is ASTM B828- Standard Practice for Making Capillary Joints by Soldering of Copper and Copper Alloy Tube and Fittings. ASTM B828 outlines proven practices required to ensure the fabrication of consistent and repeatable high-quality soldered joints between copper and copper alloy tube, fittings and components.
The standard lists several steps that must be completed for every soldered joint:
1. Measuring and cutting.
2. Reaming (burr removal from I.D. and O.D.)
3. Cleaning (oxide removal from surfaces to be soldered)
4. Fluxing (thin even film of an approved flux applied to surfaces to be soldered)
5. Assembly and support (ensure equal capillary space around the circumference of the joint)
6. Heating (heating of tube, fitting and capillary space to bring each joint element up to soldering temperature)
7. Application of solder (to displace flux from the joint and fill the joint with solder)
8. Cooling & cleaning (uniform natural cooling and removal of excess flux following completion of soldering process, never quick quench)

A more thorough review can be found at: www.copper.org/publications/pub_list/pdf/A4108-NoLeadSoldering.pdf.


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