Question about using a different flux on some old copper pipe

I was working on a boiler feed line in an old building downtown and grabbed a can of tinning flux instead of the regular paste. The joint flowed way smoother and cleaner than I expected, almost like butter. Has anyone else had a better result with a different flux on copper boiler lines?

3 comments

3 Comments

shah.shane24d ago

My buddy swears by that stuff for old copper, says it cuts through the grime better. Ever try it on a really crusty section?

xenaw2514h ago

Leo's point about a lucky fit is probably right in my case. My joints usually look like a kindergartner did them with a crayon, so any smooth flow feels like a miracle. That tinning flux might have just covered up my usual bad prep work (which is a real skill of mine). I'll take the win, but it was likely the pipe being cleaner than my usual mess.

leo_adams24d ago

You sure it was the flux and not just a really clean pipe? Old boiler lines can be crusty, but if they're cleaned right, any decent flux works fine. That tinning stuff is meant for different metals, seems like overkill on copper. Maybe you just got a lucky fit with the joint this time.