I need to replace two deteriorated laundry outlet [gate???] valves with new ball valves; they are vertically sweated to the existing pipe.

This is my first experience with sweating in an existing wet pipe situation. I know I must get the pipe completely dry before de-soldering and re-soldering - the question is: what's the best method?

The three options I've seen / read about so far are:

1) the "wonder bread" trick;
2) The commercial "plumbers bread" product;
3) Attaching a wet vac to the pipe airtight with duct tape and sucking out as much water as possible for 10+ minutes, letting the pipe dry afterward.

Since it's a vertical pipe, I'm leaning toward option 3) - seems more complete and less messy.

Comments? Suggestions?

This message has been edited. Last edited by: GottaDIYIt,

If it's vertical 99% of the waters going to run out as soon as you unsolder it.
A small amount of water will just boil off as you heat the pipe.
One way around this would be to use a Shark Bite ball valve. No soldering.

Ahhh.. I should have been more clear ... the valve end of the copper pipe will be pointing UP, not down, so, in theory, nothing will run out. I suppose I could desolder the elbow joint at the other end of the vertical pipe (about 8 inches down), allowing for a horizontal water drain, but I want to keep my soldering to a minimum.

Second vote for SharkBite or GatorBite type connections. You could spend hours trying to dry the pipes, only to have some trapped moisture get dislodged by the heat and ruin your joint. GatorBite connection will take 30 seconds tops.

standing water in the pipe will gobble up your heat, both warming up, and then rising as steam will push out your flux and absorb more heat at the sweat joint. I have cussed too much at the results over the years, enough to have softened the copper and all those pipes have developed quite a sag

ran into way too much of it redoing the basement bathroom. gave up on the toilet stop valve and put in a shark bite valve. after a month of absolutely no issues at all, used them on the sink stops and took all the others back for credit.

while they are supposedly code rated for behind the wall now, I am not that confident... all the hidden stuff got soldered. I am probably done with plumbing now in this house

note... when they say clean the pipe completely, they ain't woofin'. all along the pipe and a little past where the box says the shark bite valve will go, you need no sticking paint, plaster, tape, etc... use that plumbers' roll and make it shine bright before deburring and installing the fitting.

This connection has to be re-hidden behind drywall, so having something code rated for such is essential. I'll look into those connectors ..

But, my "best practices" question remains unanswered. How would a pro dry out a pipe if sweating were the only option?

Sometimes the answer to your question doesn't fit your choices. You can use the bread trick, you can build up a valve assembly and use a plumbers tool that will go up through the valve, past the joint and seal it off (it's basically a long expansion washer on a rod), you can try sucking the water out with a vac or you can try blowing the water out with pressurized air. Any of those can work and any of them can be a real pain as there is still the possibility that water can remain in the pipe somewhere and choose just the wrong time to release onto your sweat joint - ruining it so you have to start all over again.

You've gotten two responses from pros saying the same thing: Use a GatorBite type fitting in this circumstance.

If your installing new valves it makes no since that it's going to be covered up with drywall.
Got a picture?

quote:

Originally posted by GottaDIYIt:
This connection has to be re-hidden behind drywall, so having something code rated for such is essential. I'll look into those connectors ..

But, my "best practices" question remains unanswered. How would a pro dry out a pipe if sweating were the only option?

Some jurisdictions do not allow "Sharkbites" to be hidden in a wall. As they can possibly fail.

That's the problem with codes sometimes. GatorBite type fittings are fine to use around here. I know I have used hundreds of them and the only 'failure' I have ever seen has been caused by not completely cleaning the pipe ends prior to installing. If a GatorBite fails, you will know it right away.

OTOH, I have found leaking sweated joints that were a poor joint to begin with yet took several years to start leaking.

Not saying that a GatorBite is always better to use instead of sweating (The cost of GatorBites is very high) but in the original case above where there is a good chance of water dribbling onto the repair a GatorBite fitting has a far better chance of success than a traditional sweat joint.

Quote -- "But, my "best practices" question remains unanswered. How would a pro dry out a pipe if sweating were the only option?[/QUOTE]

You don't need to worry about "drying" the pipe, the heat from the torch will dry it. What you need to do is keep the water away from your solder area. You suggested you might de-solder an elbow down the line, if that elbow has standing water then you won't be able to de-solder it.

If the pipe you want to solder on is a vertical pipe, then you need to get the water away from that area. You can cut the pipe on a horizontal run down the line, then re-solder that later after your desired repair is done. Or if the pipe is vertical, what I do is stick a rubber tube into the pipe and then blow on it (getting a face full of water), or use it like a straw and place your finger on the end and keep pulling the water out. Also, open a garden hose valve somewhere, maybe that will drain your water out of the way.

But if you have a leaky stop valve, and water keeps slowly flowing into your solder area, that's a problem. When you heat the pipe, it will just steam up and not get hot enough for the solder to flow. So you have to stop that slow flow, or cut the pipe elsewhere and fight the slow flow elsewhere and thus using bread or whatever -- it all depends on how slow that slow flow is.

Don't even waste your time trying to solder an area where it has standing water or even dripping water. On a vertical pipe, you'll need the water to be about one foot from the solder area (that's an unofficial measurement as I have never measured it). But with a vertical pipe, once I get the water out of the way, I get it soldered right away -- forget the food, the telephone, the pet, the spouse, etc etc --get it soldered before water comes into the area. Or your just create a mess that's aggravating.

This message has been edited. Last edited by: Re-mdlr,

if you have a compressor you could blow air into the pipes from the highest point, say, a water spigot on the top floor, the air pressure will blow out enough water that you will be able to solder the joint after the pipe has dried

tried that with a can of computer cleaner "air", and wholly Moses, was that a bloody mess! kind of like blasting the crud away from spark plug holes when you're changing spark plugs. don't do it, you jam the plugs and gouge the cylinders. do it, you better have a really good set of full-around eye protectors on, because it's like walking into a sandblasting zone.

quote:

Originally posted by Jaybee:
That's the problem with codes sometimes. GatorBite type fittings are fine to use around here. I know I have used hundreds of them and the only 'failure' I have ever seen has been caused by not completely cleaning the pipe ends prior to installing. If a GatorBite fails, you will know it right away.

OTOH, I have found leaking sweated joints that were a poor joint to begin with yet took several years to start leaking.

Not saying that a GatorBite is always better to use instead of sweating (The cost of GatorBites is very high) but in the original case above where there is a good chance of water dribbling onto the repair a GatorBite fitting has a far better chance of success than a traditional sweat joint.

Not that I disagree with your post, but that is the practice in these parts. Now exactly where inspectors have found this little known codicil I'm not quite sure, but they have.

code is code, whether you like it or not.

best way to attack water in a pipe is to shut off the mains, open the lowest valve possible and drain it all off with some upstream taps open, and see if you're down to just the clinging drops in your line. if so, fan the flame across the pipe for a foot or two to steam out everything you can.

but honest to God, if there is any left to steam when you're soldering, it will blow out the flux, you will have a leaky joint, and I have not been able to fix those. yeah, yeah, take off the fitting, sand it down to clean copper all around, reflux and use a new fitting, etc, yeah yeah.

it don't freakin' work, folks. cut back and start over. don't waste the time. time is money.

and never leave anything weeping behind you.

This message has been edited. Last edited by: swschrad,

Excellent discussion, gentlemen! Exactly what I was looking for! Lots of good ideas to chew on ...

I'll let you know how it turns out..

Thanks Again!

I still have nightmares from that one basement plumbing job where I just had to sweat a couple of fittings - a matter of a few minutes.

Four hours later I finally got it done. Working in the basement of a two story house (three floors total) completely defied any use of bread, or compressed air or using the torch to dry. Every time the heat from the torch went up the pipe it found another trapped pocket of water to send town to my sweat joint.

Additional data point: a pic of the pipes in question. Here's what I saw after cutting back the drywall around the laundry outlet. VERY sloppy work by the original builder. Assuming I just cut off the defective valves at the highest point, Do I even have a prayer of cleaning up this pipe enough to use a SharkBite adapter to the new laundry valve?

Look for some plumbing sandpaper - it comes on a roll about 1-1/2" wide. It's a cloth-type sandpaper so very flexible and tough. You tear off a length, wrap it around the pipe and pull it back and forth. With it you can clean off 100% of the excess solder.

Agree, this is a pretty sloppy job. Whoever did this subscribes to the "If some is good then more is better" school.

BTW, I my plumber just emailed me the invoice for our latest project. In it are not only the parts lists including Sharkbites but a copy of the green tag from our plumbing inspector.

Here's your chance to fix this right.
If it was mine I would clean off the copper pipe where it come out of the wall horizontal, if there's some blobs of solder I just heat the pipe up enough to get it soft and wipe with a damp rag, then cut the pipe, unsolder where the pipe goes into the faucet and toss it in the trash.
Fix the drywall. Once the drywalls in place add the escuntion and an angle 1/4 turn 1/2 slip X 3/8 compression shut off valve. Then you can use a stainless steel flex supply line and never have to go though all this again.