Sweating Copper

[crokett]

I decided to invest in the kit necessary to sweat copper. I have to attach the threaded fitting for the bath spout this weekend and figured with all the other plumbing changes I will be doing in the near future it will be 25 bucks well spent. Now, I haven't actually soldered copper since I was a teenager. As I remember it the steps are:

1) Sand everything till it is bright and shiny. The ID of fittings gets the wire brush.
2) Wipe everything clean
3) Heat the fitting a little and flux it
4) Put the fitting on the pipe
5) Heat one side of the fitting (not the pipe) and apply the solder to the other side. Remove the heat while I am actually applying solder. The solder will flow around and into the joint.

Anything to add?

[ragswl4]

I purchased a wire brush (inexpensive) that cleans the outside of the pipe as well as the inside of the fitting. The brushes come in 1/2 and 3/4 sizes. Really quick to do and beats sanding. Clean, then apply flux to pipe and fitting, then heat and apply solder to joint. Continue with heat until solder flows into the joint. Don't over do it with the solder, doesn't take a lot. Some folks put water on the joint to cool it but I don't. Take care not to apply heat directly to the solder, just wastes it.

[Uncle Cracker]

One more thing that goes without saying (but I'll say it anyway) is to make sure the pipe you are soldering doesn't have water standing in it, or you will just boil the water, and not melt the solder. Otherwise, it looks like you've already got all the process correct.

[ragswl4]

One more thing that goes without saying (but I'll say it anyway) is to make sure the pipe you are soldering doesn't have water standing in it, or you will just boil the water, and not melt the solder. Otherwise, it looks like you've already got all the process correct.

Good point and if it does have water in it, stuff some stale bread into the pipe to absorb the water. Once the soldering is done and before you hook it all up, apply water pressure to the pipe and it will blow the bread out.

[jhart]

I've always used a wet rag to wipe around the sodered area and keep it nice looking if I get too much in the joint nd it overflows some.

[Mr__Bill]

You may find that MAPP gas which burns hotter than propane makes the job easier. It's more expensive and probably should not be used later in a lantern or camp stove but the hotter flame heats the fitting faster and keeps you from heating the pipe too much.


Bill. on the Sunny Oregon Coast where the sun actually is shining today!

[docrowan]

Water in the pipe was a major problem for me the one and only time I tried sweating a pipe. It wound up even giving a professional plumber and his assistant grief. I've been fortunate in not needing to do it again, but I'm kinda skeered of it now. I didn't like stranding my family without water for a whole weekend and I felt like a complete idiot. I'd advise having a plumber's phone number on hand just in case. The ones I deal with love me to handle whatever I can and will give me advice so they don't have to come out. They're more interested in doing commercial work than my piddly little projects.

[cabinetman]

One more thing that goes without saying (but I'll say it anyway) is to make sure the pipe you are soldering doesn't have water standing in it, or you will just boil the water, and not melt the solder. Otherwise, it looks like you've already got all the process correct.

Making sure there's no water in the pipe can be deceiving. You can stuff whatever will work in there, but to make sure it stays dry during soldering, shut off the main water supply, open a spigot or faucet preferably lower than the area you're in to allow any water to drain down.
.

[Rich P]

Anytime I solder pipes with water in them I do exactly what cabinetman suggests. If I have to I'll use compressed air to be sure there is no water. Even a small puff of steam will blow out solder from the joint. Sounds like a lot of work but it is much easier than pulling a soldered fitting off and starting over! (Believe me I am speaking from experience.)

[sscherin]

I also prefer to wipe down the joint with a wet rag after its done to remove any left over flux.
Flux is an acid and over a long period of time it will corrode the copper.

I'll 2nd the mapp gas.. It's hotter and makes the job quite a bit easier.

Oh yeah.. The self igniting Mapp torch is the best way I've found to get the Charcoal Chimney going for the BBQ

[JimD]

This is minor but you heat the thicker piece. If you are soldering a fitting that is thicker than the pipe, you put the heat more onto the fitting. If you solder a valve, you remove the valve seat and then put the heat directly on the valve ignoring the pipe completely. You want both pieces to reach the same temperature at the same time but when one is much bigger than the other, you have to heat it more.

I also do not necessarily remove the heat when applying solder but I do not put the torch directly on it either. When it flows readily, it is time to remove the heat but as you get up to temperature it is good to keep trying the solder and it's OK to keep heating while you test.

If you have to solder near wood, it is really nice to have one of the little 8 or 10 inch square blankets they sell in the soldering area of the home center to help protect the wood. They work pretty well.

To get water out, open everything you can find. If you still have water, open something else. Sometimes you need the air to get in to get the water to go out.

Jim

[chopnhack]

+1 on the MAPP, its almost a necessity ever since they changed the formulation of the solder. Make sure also to use a good soldering paste (flux), some have some tinning in them and make it easier to sweat a bead.

[Raffi]

Sweating threaded fittings onto copper has been a nightmare for me in the past. The problem was that I could never get the fitting hot enough to take the solder and would end up just damaging the pipe/melting all the solder without sweating the joint.

On the last job I did, I found that home depot had threaded fitting that had an extended nipple (if you will) - made the job a TON easier. Heat the nipple, sweated the joint bing bang.

Also, for water in the lines, I have seen a Vitamin E looking "pill" that you can put into the pipe, that seals it from water/steam, but dissolves when you turn the water back on.

Raffi

[master53yoda]

About the only thing that has been missed is that the solder flows toward the heat source so once you get the solder flowing move the heat source to the fitting side of the joint and it will pull the solder into the joint, if you heat the pipe it will pull the solder out of the joint.

If you are using threaded fitting solder the nipple into the threaded fitting install the threaded fitting and wrap with a wet cloth to protect the fixture. Then solder the other end of the nipple into its fitting. always open the valve in the end of the run you are working on to prevent pressure build up in the fitting you are soldering on.

[Kristofor]

<snip> I've been fortunate in not needing to do it again, but I'm kinda skeered of it now. I didn't like stranding my family without water for a whole weekend and I felt like a complete idiot. <snip>

While plumbing in general is my least favorite home task, sweating pipes on the clean side doesn't really bother or scare me. As with anything you don't do regularly it's a good idea to make sure the local hardware store will be open so you can buy more parts if needed.

My other recommendation that would help with not leaving the family high and dry is to go crazy with the shutoff valves. If I need to work on a line that doesn't have one already I'll take the time to add it. When one sink/toilet/washing machine/etc. is all that's out of commission there are far fewer complaints if you decide to stop and watch a football game halfway through the process...