Why would you have to use a piece of bread while sweating a copper pipe joint?

Answer 1

Bread? are you kidding me? Yes you are right good old white bread.

When sweat soldering, one of the, if not THE major factor in sweat soldering besides the joint being perfectly clean is the ability to totally heat the joint - all the way around. No doubt you've attempted it before, you have turned the water off and opened the lowest available faucet to drain the system. You have cut the pipes and are now ready to solder. You notice that even though you have drained the system there is still an occasional drip that comes from the end of the pipe. If you waited until all of the water drained out of all of the pipes you would probably have to finish it tomorrow, and as you and I both know that just will not do, seriously, there's dinner to make and showers to take. So you think that if you turn the torch way up you will be able to heat the joint fast enough to evaporate that pesky drip drip, well think again. Even one drop of water running into the joint will ruin the most beautiful sweat solder joint. It will leak. Maybe not right away, but eventually, and most likely at the very most inconvenient time, like while you are away for 2 days.

Here's where the wonder bread comes in. Take that slice of wonderful and roll it into a doughball. Wheat bread won't work, it's just too healthy and nutritious to roll into an effective ball, white bread is the only way to go.

Take that doughball and pack it into the pipe on the high side, grab a stick and jam it up there about a foot and a half or so, go for a second slice if the drip is really ornery. The bread ball will make a nice blockage in the pipe, now hurry up and finish that joint.

Finished? Now beat feet to that faucet you opened up earlier and watch as that dough ball oozes safely out into the drain, believe me you don't want that thing ending up in your shower head when the missus goes for a shower later.

There, a leak free soldier joint that won't be the reason your freezer was reduced to a pile of rust when you were on vacation in Las Vegas,.