![]() Now, the trick question: How many bad connections does it take to bring down wallboard? We know the answer to that one too. Solder alloys whose performance is based solely on price will cost about 18 cents per fitting. A high-performing alloy with all the strength and flow you will ever need costs about 22 cents per fitting. Any one pound spool will connect approximately 360 90ø fittings. Lower strength numbers can sacrifice the integrity of the joint, leading to that dreaded callback.ĭo the math any way you like and you will find that choosing a premium alloy will only cost you a fraction more per connection. Higher melting temperatures translate into more time and more gas used on each sweat connection, and the limited flow characteristics of low-priced alloys means more wasted product. Obviously, lower grade alloys will run you a little less at the counter, and quite possibly, cost you a little more at the job site. Individual lot numbers are printed on each roll, allowing you to request lab analysis from the factory on the metal composition if there is ever a question from an inspector or customer. Alloys meeting this strict standard are assured to be safe for potable water applications under any circumstance, which cannot be said for all ASTM B32 lead-free alloys. NSF 61 is an extra layer of protection that traces the product back to the manufacturing facility, and to the component materials. Regardless of your choice of premium alloy, selenium or silver-based, you should seek out products that have achieved NSF 61 certification. Just enough heat to get you started, not too much heat that you spend time waiting on the solder to set up. The liquid solder will not support the weight of the tube and any disturbance will cause the solder to fall out. If you use more heat than necessary, the joint will stay liquid longer. It takes very little time to sufficiently heat the pipe for soldering, far more time for the pipe to cool down with ambient room temperature. It is important to remember with extended (pasty) workable ranges, more time is required for the solder alloy to set up and cool down. Once the connection temperature goes beyond 640 degrees F, the alloy will loose the ability to flow into the fitting cup. Simply put, the alloy will melt around 440 degrees F and achieve capillary action at temperatures close to 640 degrees F. Silver-bearing solders typically have a 200 degree F workable range. The larger the tube, the more heat becomes an issue in the performance of the alloy. Silver added to the alloy will exhibit an extended pasty (working) range, ideal for sweat connections on large diameter copper. Silver-bearing alloys are plentiful and available from nearly every manufacturer. ![]() The alloy composition achieves quick flow and set up, a perfect combination for the majority of tube sizes joined today. When you add the lower heat tolerances of current ASTM B813 water-soluble fluxes to the equation, a lower temperature joining can have significant advantages. Premium alloys with a high selenium content lower the melting temperature to 410ø F, very close the melting temperature of traditional leaded solders. Premium solders boast a number of advantages over the generic lead-free alloys. ![]() The high performing lead-free alloys will contain a mixture of Tin (Sn), Copper (Cu) and either Silver (Ag) or Selenium (Se). When the code changed from leaded to lead-free solder for potable water, the ASTM B32 specifications were changed to Sb5 throughout the industry.
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