A few years ago I remodeled my bathroom and learned how to sweat copper pipes. I've always been able to do it successfully since then, but I've always wondered exactly how and why it works. I've done some searching on the web but most of what I find are "how to" articles and videos, but nothing that explains the specifics of how and why it works. Can anyone give me some answers to these questions that have bugged me?
What exactly does the flux do?
- What happens if all the flux burns away before the solder melts?
- What if you didn't use flux at all?
- What is flux in the first place?
Where exactly should you aim the flame? (I've seen differing reports on this one)
- Right at the joint (where the flux is)? (in my limited experience, this seems to burn away the flux immediately and sometimes causes problems)
- At the copper pipe, an inch or so away from the joint?
- At the fitting that the pipe is being soldered into?
What exactly is the capillary action that draws the melted solder into the joint?
- What causes it and how does it work?
- Sometimes I find myself in a situation where the solder melts but just drips right off the pipe instead of getting sucked into the joint. What have I done wrong? I usually have to clean everything off and start over when this happens