Can I swap from sweat-on to compression stop valve?


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Old 07-24-17, 09:19 AM
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Can I swap from sweat-on to compression stop valve?

Can you ever clean enough solder off an old stub-out with sweated valve to get a compression valve to seal?

I have a leaky kitchen faucet that needs replacing & the valves are so corroded the handles won't turn. They're soldered to the stubs and stub is long enough to heat up without burning down the house, but not long enough to just cut off the valve.
I'm also concerned that heating the stub enough to wipe off the old solder might cause a leak at the other end inside the wall.

I never have any issues working with new pipe but often run into problems working on old. Any tips appreciated...
 
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Old 07-24-17, 09:46 AM
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Probably can, Will need to heat ans and off old solder. I would use these instead.
https://www.lowes.com/pd/SharkBite-B...lve/1000182523
 
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Old 07-24-17, 09:49 AM
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Can you ever clean enough solder off an old stub-out with sweated valve to get a compression valve to seal?

Yes

I have a leaky kitchen faucet that needs replacing & the valves are so corroded the handles won't turn. They're soldered to the stubs and stub is long enough to heat up without burning down the house, but not long enough to just cut off the valve.
I'm also concerned that heating the stub enough to wipe off the old solder might cause a leak at the other end inside the wall.

I never have any issues working with new pipe but often run into problems working on old. Any tips appreciated...
You have to heat quickly. Heat and remove valve with pliers. Low flame. Have a rag handy and wipe pipe. I usually grab whole pipe with rag and pull/twist. Repeat. Then emery it..

Have spray bottle of water handy.

I often wet inside of wall with spray bottle before I start. Reduces chance of something catching fire in wall. And Ill spray after I am done with each stub to cool rapidly..
 
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Old 07-24-17, 09:53 AM
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Unless you can drain the copper stub out, you'll have a very hard time getting enough heat on it to melt the solder.
 
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Old 07-24-17, 06:35 PM
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As said, the fitting needs heated quickly and pipe wiped off, Mike covered it all.

Just wanted to add you might want to use MAPP gas vs propane. The MAPP gas burns hotter.

If you shut off the water and still have minor dripping, shove bread into the pipe to stop the leak and flush out the new valve into a bucket before installing any faucet.
 
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Old 07-25-17, 12:04 AM
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If you shut off the water and still have minor dripping, shove bread into the pipe to stop the leak and flush out the new valve into a bucket before installing any faucet.
Just open a lower hose bib outside if you have dripping. The water will divert there instead of coming out the sink .. ( Old plumber trick)
 
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Old 07-25-17, 06:38 AM
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Originally Posted by lawrosa
I usually grab whole pipe with rag and pull/twist. Repeat. Then emery it..
Mike should I flux the pipe before re-heating for the 2nd wipe? I know flux can help the solder smooth out but not sure it makes any difference if wiping it off anyways.

In any case I would trust a brass compression fitting to seal on wiped-off solder more than I'd trust a Sharkbite's O-rings. Would a smear of sealer on the pipe before sliding on either a compression ring or Sharkbite be even better? Sort of a "tape + paste" redundancy line of thinking...
 
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Old 07-25-17, 07:05 AM
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Wouldn't it be easier to just solder on new valves and not have to worry about leaking?
 
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Old 07-25-17, 09:04 AM
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I'm just not a fan of soldered stop valves. Valve replacement is so much easier if it's a compression mount.
 
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Old 07-25-17, 09:06 AM
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No need to flux pipe as you will use emery to clean.

But as stated ones you put compression valve on it will mess up end of pipe for future repairs.

I dislike sharkbites

If you got that far with removal just sweat new valves on.

Clean pipe and valve with emery and brush.

Flux. ( Use Otatey #5 from home store)

Have valve open when soldering.

Be quick. Dont dilly dally.

Let cool completely before closing valve

Use a wet rag to help cool.

Dont forget spray bottle advice..
 
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Old 07-25-17, 11:58 AM
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I'm just not a fan of soldered stop valves.
I've never had to do one but I've though of it, bit nervous if I did one.

Valve replacement is so much easier if it's a compression mount.
I've never had compression either, no idea. My brother had something like you and
I suggested he solder on this then screw on a valve. He did and it worked fine.

Name:  sweat copper.JPG
Views: 3249
Size:  31.8 KB

Room could be a problem for you, just a thought.

Good luck, what could happen??
 
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Old 07-25-17, 12:13 PM
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Baldwins suggestion is excellent....

I would do exactly that. You are sweating on the adapter and that will enable you to change the valves easily in the future.

The 1/2" pipe thread valves are also easier to install than compression.

If you do use compression valves, tighten the nut using two wrenches until the ferrule just grabs the pipe, and then tighten 1/2 turn only, check for leaks. Over tightening will cause leaks and damage/indent the pipe and the ferrule will not pull off without severely deforming the pipe.
 
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Old 07-26-17, 05:08 AM
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If the sink faucet is connected to shutoff valve with a female threaded fitting, all you need to do is piggyback a quarter turn shutoff valve to the existing shutoff valve. No de-soldering required. Shutting off the water supply to the existing shutoff valve is required.
The piggyback valve threads on to the old shutoff valve and the water line from the sink faucet threads on to the other side of the piggyback valve. One brand is Keeney # 380734.
 
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Old 07-26-17, 07:15 AM
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Originally Posted by lawrosa
But as stated once you put compression valve on it will mess up end of pipe for future repairs.
"Mess up"? Aren't compression fittings universally the same and the nut/ferrule can be re-used on a new valve?
Maybe I've just been lucky that when I've done that in the past it's worked flawlessly.
The sweat-to-threaded adapter would also work but sticks out farther from the wall.
 
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Old 07-26-17, 12:44 PM
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I don't like to use old nuts and ferrules, although it will work if the threads are the same and the new valve will slip onto the pipe far enough to "meet" the old ferrule.
I sometimes will have to trim about 1/8" off the end of the copper tube to get the new valve to sit against the ferrule.
I also apply Teflon paste to the new valve's male threads even though it is not needed in normal installs.

(Prepare to be bored)
A compression ring/ferrule should pull off easily (using a puller) and leave no indentations in the soft copper. It should leave minor cuts that can be cleaned with emery cloth.
It took me a long time to learn to not overtighten.

When tightening a ferrule, you are not trying to compress the inside of the ferrule to the copper.
Only the very thin beveled edges of the ferrule need to grab the pipe, and some would be surprised how little torque that takes.
 
 

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