Using Bread to Sweat a Leaking Copper Pipe





Introduction: Using Bread to Sweat a Leaking Copper Pipe

This Instructable shows how to use white bread and standard pipe sweating techniques to repair a leaking copper pipe.  There are a ton of excellent instructions online and here at Instructables for pipe sweating, this isn't meant to replace those, but rather to show a trick I learned over a decade ago for sweating a pipe that is actively leaking.  Normally you hope that by cutting off your mains and draining your lines you can eliminate any water leaking from the pipe you're trying to sweat.  Sometimes you can get any extra out by using a shop vac.  But sometimes you're screwed and a persistent drip will make it nearly impossible to do a proper solder because boiling water coming through a seam doesn't allow for the solder to set where it should.  This is a cheap work around.  There are commercial products that produce a similar result, usually wax plugs or other things that melt away as you sweat.  That might work, but I have to imagine some wax is left behind because by the time you turn the water back on the wax won't be liquid anymore, but I digress.

I apologize if my pictures are a little dark or blurry.  I had to do this in the dark while it was raining on my back, but we don't usually get to pick when these things happen, so I'm just glad I remembered to take photos at all.

Tools and Materials:
Pipe Cutter
Couplers (correct diameter)
Extra length of pipe (correct diameter)
Non Lead Solder
Hunka Bread

Step 1: The Situation

If you saw my last Instructable on making Motorcycle Saddle Bags out of 40MM Ammo Cans  there was a step in which we sprayed down the cans with paint stripper and then rinse them with the hose.  Well, if you've ever watched somebody walk off with a garden hose that hasn't been secured to anything other than the faucet itself, you know what's about to happen especially if that faucet is sticking way out.  Some copper is about to get mangled.  Secure your hoses between you and the faucet.  Then maybe you won't ever need this bread trick.

In this case I noticed a pretty good twist in the pipe right against the wall and a small crack that was leaking water, and this is right above my main.  There are other Instructables on patching pipes, making the cuts, and sweating so I'll move fast through those parts.  I'm not trying to compete with those and they are excellent, I'm just showing a trick for doing it when leaky.  So I punched out a bit of wall and cut out the bad section with a pipe cutter.  Use a pipe cutter, as much fun as power tools are, they and copper piping do not go well together... you will not get straight cuts and straight cuts are crucial to prevent leaks.  Most copper pipe cutters cost less than 10 bucks.  I bought one today for 8.50 after realizing what a disaster my grinders metal cut off wheel was making. Use standard sweating techniques to put a new pipe section in and the couplers needed, right up until the last bit which never quite quit leaking.  I tried for about 5 minutes to sweat this piece on before realizing it would be impossible and remembered this trick my old boss taught when I was a kid working a summer job. 

Step 2: Pipe Preparation

Just like when normally sweating a pipe, clean it up with plumbers cloth.  You can use emery cloth or whatever normally, but emery cloth tends to deteriorate as soon as it gets wet and you need to clean up the leaky side.  Use a pipe brush to clean/mar the inside of the coupler as well if you didn't hit both sides of it on the last sweat.  Brush flux on the outside of the leaky side and the inside of the coupler.  I know I could have done a better job on the clean up here, but I had just banged my head into the garage door and it was raining, so there was quite a bit of swearing and not giving a crap happening right about here.

Step 3: One Way to Use Bread That Won't Make You Fat

Crucial: Before you put bread in the pipe have your torch and solder at the ready.  This will only give you a few minutes of grace time before the leak starts again.

I only had some white bread laying around that I baked last week.  It's delicious bread and I'll have to make that into an Instructable one day too, I'm a much better baker than a plumber.  Anyway, this was a thick end cut off the loaf that was left.  You need probably about half to three quarters of a piece of Wonder Bread to give you an idea... maybe a little more or less depending on the volume of your leak.  If you're getting a lot of water to the point where this doesn't work, you've got something else going on... figure that out first.  You need enough bread to absorb the leak for a long enough period to complete the sweating.  I used this amount of bread and this is a 1" pipe and it worked fine.

Stuff your bread into the pipe on the leaking side. Stuff it in as far back as your finger will reach.

Step 4: Sweat

Shove the pipe into the coupler and sweat it with your solder.  Other instructions will let you know, but I will repeat, you don't melt solder with the flame, you melt solder by heating up the joint until it is hot enough to melt the solder by touching it with it.  If you try and heat the solder with the flame and just sort of paint it on you will become extremely frustrated with how badly this is going for you and very likely light yourself on fire to bring an end to madness.

Yes my soldering is ugly, cut me some slack.  It was raining and dark, I was drunk and had a huge knot swelling  up on my head and I'm no plumber.  The solder held so I'm happy.  Tomorrow I guess I'm cleaning up this hole in the wall.

Let the pipe fully cool off, to the touch, before kicking the water back on.  Don't try and splash any water or anything on it to speed up the process, this might shock your whole mess and result in another leak.  Once it's cooled off put pressure back in the pipe by turning on the water main, and open your hose valve and bread bits may or may not shoot out.  If you have a little filter in there you can take that out and speed up the process, but the bottom line is the junk trapped in the pipe is bread and will pretty quickly disintegrate and get out of your system.

Step 5:



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    29 Discussions

    Difficult to tell from the images, but it appears that your valve is entirely outside the structure. From your image - all covered up in heavy clothing - it appears you are in a Northern clime.

    You might want to consider (when sober ;) replacing that valve with a Frost-proof assembly.

    It also appears as if the incoming line is exposed to the elements. Again, a 'bad thing' if freezing weather is common.

    And, for the other non-plumbers reading this before attempting a repair - take a minute or two to search YouTube for "Soldering Copper Pipe" before getting out a grinder to cut out the 'bad sections!"

    One might also look to PEX fittings and No-Solder fittings.

    I would have suggested moving the hose valve/spigot assembly off to the left or right so it could be securely fasted to the structure, then 't' ing off the main pipe to connect it to the line. You could, also, raise the spigot to a more comfortable height in the process. And, depending upon what was in the other side of that wall, installed a Frost-proof spigot and valve assembly taking the feed from another cold water line inside the structure.

    One trick that worked for me as a temporary fix (allowing time to research the 'Right Way') was to cut a piece of rubber sheet to cover the crack/leak and secure it with a stainless steel hose clamp. I did that on a feed line from the meter in Florida years ago and never got 'round to fixing the leak properly. As far as I know that temp fix is still in place!

    Use silver solder instead and you will get a better joint. Also it would not be a good idea to do this on the main feed to the hot water cylinder. Another option also would be to sleeve the joint so as to make it stronger.

    As for radiators. I have used Egg, Pepper and once when I got really desperate curry powder. The egg one is simple, separate the white and drop it in to the radiator. fire up the engine and it will clog the hole. Same deal with the powders as they mix with the water and are ejected out the hole eventually clogging it.
    Something people forget to do that makes this fail however is to put a match stick under the pressure part of the radiator cap so your radiator will not build up pressure to blow the seal out. It is a temporary fix.

    2 replies

    I too, have used black pepper, but you can use anything that will "swell" to a larger size, ... I have also either raised the pressure relief top on a radiator cap, or only put it on until it is on the 1st lock, ... (which will secure the cap to the radiator mount, but alleviate the pressure as it builds up), ... or take the cap off altogether, ...

    just one thing more, ... if you do put stuff in your radiator as a temporary plug, be sure to always change the thermostat, before using again, after a more permanent repair has been made, ... mainly because you also need to do a flush, & fill, to your coolant system, to keep any remaining stuff from causing your vehicle to overheat, ... a thermostat is much cheaper to replace than a head gasket, or to have the whole engine rebuilt/remanufactured, ...

    Thanks... in this application I did use the sleeve, referred to as a coupler in the instructions... were you referring to something else I don't know about? What I used is a collar about 2" long made for the 1" diameter pipe I had crack here. I used silver solder here too... the lead free variety, just because I assumed it's bad to have lead anything in your plumbing/water.

    The match stick knowledge on the radiator fix is something I definitely would not have known but makes total sense. Thanks!

    Interesting, thanks for sharing.

    Years ago I used ground paprika to fix a leak in the car's radiator. It is an old road trick. It works!

    9 replies

    Thanks... good tip with the paprika, did you just pour some into the radiator and it sealed the leak or what? I haven't heard that one.

    Yes, you must put a soup spoon of paprika (Spanish: pimentón molido) in the hot water when the motor is running. After a few seconds the little flakes of paprika clog the leak. The fix is valid for some hours or days, you must fix "really" the leak soon.

    so it is kind of like cracking an egg into the radiator to stop a leak .. it is by no means a long term solution to the leak, but it should get you to where you need to go to get the leak truly fixed .

    guys, I have used black pepper from a restaurant to get me home with a leaky radiator, ... also used it when the heater core also started leaking, ...

    sounds like the paprika will work if it is added to the radiator regardless of the temperature of the radiator. The egg only works if the radiator is hot.

    sorry about getting the commets off track badpanda. Great instructable.


    2 years ago


    I've used bread for years but today I feel like a total amateur. I repaired the copper pipe outlet from the water heater to the entire system but I've lost pressure throughout. The first repair was at a 90 deg elbow off the main hot water line with bread as a moisture bearer. I soldered the elbow and a coupling joint; let it cool; cut in water supply; no joint leaks. I thought I had check the old piece of pipe I used from the elbow to the coupling for possible leaks but didn't do so well. There was a pin-hole leak but instead of removing the previous installation, (I've had SO many problems with draining water from my water system and sweating joints because of moisture.), I decided to cut the pipe and install a slip coupling. After using bread again about 3 inches up the down pipe, I soldered the slip coupling in place; let cool; turned on water supply; no leaks AND, NO pressure at exit points. Pressure gauge indicates 60psi on system. All aerators are clean, double sure. Since I repair the hot water side I could understand if there's a blockage but on the cold water side too? Flushing a toilet drops the pressure at the wash basin to barely running both hot and cold. I used a "shopvac" with the water open trying to suck out any debris. That didn't work. My thoughts are; I crystallized the bread and it's stuck to the pipe thus blocking the flow at the joints or got fed into the system; I used too much solder and it's blocking the flow at a joint or got fed into the system; I could remove the installation and repair using mostly screw-together piping except at the elbow; drain the system and try to suck out any debris. I'm still puzzled as to why a blockage on the hot water side is affecting the cold water. I could understand if the blockage is at a faucet but not a single valve such as a washing machine connection. I sure would appreciate any help from anyone in the know. Thanks you!

    I've been using bread forever - you can use a grain bread but it disintegrates more slowly and clogs up the aerators (the little screens) on the ends of your kitchen/bathroom spigots. I guess the grains swell, or something. In a pinch, you can use a whole grain bread, though. Just don't panic when your spigots don't work - just unscrew the aerators and clean out the plug of bread.....

    Just used a bagel, worked well! First 2 attempts without bread failed as the pipe continued to drip and the solder would not suck in.