Soldering Sillcock to 1/2″ Copper Pipe
I need to replace the 1/2″ copper pipe that feeds an outdoor sillcock. About 2 feet of the pipe is exposed to the outdoors and burst this past winter. My problem is that I’m having a tough time getting a good solder joint at the sillcock. I’m using MAP gas, cleaned everything, used flux and 50/50 solder. I think the problem is that the flux is burning away before the sillcock gets hot enough for the solder to melt. Is there a better way to do this? Thanks in advance for any help.
Replies
Make sure that the valve is open. This not only lets any steam escape, but will tell you if water is running into the pipe. I don't know why, but so often when I sweat a pipe that I thought was dried out, water trickles in to that pipe from who-knows-where as soon as I start to heat it up. It can a LONG time to evaporate all that water, after which the sweat usually works (if I haven't toasted the pipe or fitting by then).
Andrew
I actually dis-assembled the sillcock before soldering to prevent the heat from melting the internal washer, so the valve is fully open.
I was wondering if there's a trick to soldering such dissimilar pieces: a thin copper tube to a relatively heavy sillcock.
You might try soldering a thread adapter and then using a threaded sillcock. BTW. 50/50 solder contains lead and has been illegal for years. I use silver solder. Flows like 50/50 but contains no lead.
That's what I do. For the non-professional plumber, the ease of soldering the adapter vs. the heavier valve is well worth the few cents for the extra part. Plus it's much easier to change the valve next time, turning rather than burning. It takes some practice to solder to valves without burning up their plastic parts.
-- J.S.
Great idea! (although I'd still like to know how to do the soldering)...
It's hard to tell what you are doing wrong in a blog. Could be a lot of things. If it's cold or windy. That would make it harder to get a good joint. Is the flux you are using old. If it's as old as your 50/50 solder that could be a problem. Try removing all of the guts from the sillcolk. There will be less to heat up and at least you won't end up with a good joint but the guts have been so cooked that the valve doesn't seal. AND, BUY NEW SOLDER AND NEW FLUX THAT DOES NOT CONTAIN LEAD.
Thanks everyone for your helpful advice. I was successful soldering the pipe to the sillcock by pre-heating the sillcock itself first and then moving closer to the pipe. Had it not worked, I was ready to solder on a threaded fitting and get a new sillcock that accepts threads. (By the way, the solder was lead free. I mistakenly said it was 50/50 in my original post. Sorry for the confusion).
Missed this post over the last couple of days.
I sweat a lot of copper pipe, although I am not a plumber. You seem to have found the solution, so congratulations.
A general rule when sweating fittings or valve bodies on copper pipe is "heat the fitting, not the pipe." That is, as you found out, apply the heat to the point you want the solder to flow too.
If the cleaning and fluxing are done correctly, and you heat the fitting only, when the pipe reaches the melt temperature of the solder, it will literally be sucked into the fitting, as well as crawl completely around it.
I got that advice from a master plumber, some 28 years ago, and my failure rate on copper pipe up tp 2 1/2" is near zero.
Dave
Leaving the valve open is a good idea, that will let steam or water out. You could also tin, pre-solder skim, the sillcock to assure the the solder has spread evenly.
It's a little tricky sweating copper to brass because of the difference in thickness. The adapter's a good idea. But if you want to stick with the sillcock you've already bought, you might try bringing the tip of the torch back a little so it heats up the brass sooner than the copper- kind of sneak up on the Cu. The flux should be okay this way, too. It will start to crackle and run, but if you did it right the joint should be the right temp to add the solder. Also, if there IS water seeping intop the mix, you'll never get a good joint. Take a piece of white bread, no crust, ball it up and stuff it in to the pipe a couple of inches. this will buy you the time you need for a dry repair. If it doesn't turn into toast, it will melt out when you flush the sillcock