Chinese copper tubing has higher amount of more trace impurities than in the past. I want to say phosphorus and sulfur. Makes it more brittle, harder to braze. But being that's pretty much all we can get anymore I just had to adjust my soldering techniques and make it work.
I predict ............... at some point in the near future. The boneheads of today's maintenance force. Will loose the skill required to solder, unable to hold a cell phone while looking like they are working.
I am curious what you changed, amount of heat, time, flux, solder?
Thanks in advance.
Sorry, I still say 'soldering" when refrigerant tubing uses "high temperature brazing". As I recall it has to do with the temperature that is the dividing line between soldering and brazing.
The solder I used to use was a self-fluxing type that was standard in the industry. I changed to a different brand of soldering alloy that I think had more silver (for better flow) and used a paste flux (I think it was made by Oatey). I used to use flux as a beginner but it caused pin-hole leaks so a boss made me drop it.
Scrupulous cleaning was also par for the course - even on brand new tube and fittings! I used to use sanding cloth exclusively but went to steel wool for alot of cleaning jobs as it was cleaner.
Brazing or soldering aluminum used to be impossible. I never tried it. Trane had a connector kit for making aluminum to copper transitions, as they tried aluminum tubed coils back in the 80's. If the factory aluminum to copper junction failed that kit was the only approved way of joining them. maybe they have something that works now?
