QA

Quick Answer: How To Sweat Solder Copper Pipe

Can you overheat copper pipe when soldering?

Overheating is a major problem when brazing or soldering copper pipe because the flux will burn (become oxidized), stop working, and become a barrier to tinning. In addition, a heavy oxide can be formed on the pipe itself, preventing a bond from forming between the filler metal and the pipe surface.

Do you need flux to sweat copper pipe?

Flux prevents the copper from oxidizing as you heat the copper with the torch. You can solder without flux, but it is really difficult! Flux is applied to both the pipe and the fitting with a handy miniature paint brush. You do not need massive amounts to be effective.

What kind of solder do you use to sweat copper pipe?

Buy lead-free solder that’s designed for copper water pipes; you’ll find it in the plumbing section of the store. Solder with lead is still available, but the lead can leach into your water supply, so don’t use it.

How long should I wait to turn water on after soldering?

30 seconds should be long enough. Once the solder has solidified, you are good to go. The water will only make it solidify faster by cooling, but if it is still molten, the water pressure will separate and/or pollute the joint.

Can you Resolder copper pipe?

Soldering vertical copper pipe shouldn’t be too different from working horizontally. If the joint and tip are hot enough, the solder should flow right in. Heat the middle of the fitting and apply the solder as soon as it starts to melt. Remove the heat once the solder starts moving.

Can you solder copper pipe without using flux?

You “can” solder copper without flux, without scraping (sanding or filing) clean the two surfaces, and without ensuring there is a close even fit between the two surfaces for the molten solder to wick into and provide a quality joint.

Can you solder copper with a soldering iron?

You can fix it using a soldering iron, as long as you follow the basic rules of soldering copper wire and make sure you’re careful and attentive during the process.

Why is the solder not sticking to copper pipe?

the solder is hot enough, but the copper is not hot enough. Heat the copper more before applying the solder. The join is not clean enough. If you’re using a good flux, then the copper isn’t clean enough.

What is the melting point of copper solder?

The melting point of copper (Cu) alloy UNS C12200 is 1,981°F/1082°C. As such, the filler metals for soldering and brazing copper and copper alloy tube and fittings must have melting temperatures below this temperature.

Can you solder copper pipe with water in it?

Don’t try to solder pipes with water in them. Soldering a joint in pipes that contain even tiny amounts of water is nearly impossible. Most of the heat from the torch goes into turning the water to steam, so the copper won’t get hot enough to melt the solder. Stop the trickle of water with a pipe plug.

What is sweat soldering used for?

Sweat soldering is a simple and fuss free way of joining two metal surfaces together, one on top of the other. It is great for flat surfaces and ideal for seams, where neat solder application would otherwise be tricky.

Why is it called sweating pipes?

The walls of copper pipe, however, are too thin and soft to be threaded, so a different sort of fitting is used, called a sweat fitting. It’s called that because the process of joining the various elements using solder involves heating them with a propane torch until they seem to sweat.

Is rosin core solder good for plumbing?

Typically, electrical solder contains rosin core flux; plumbing solder uses an acid-based flux. So it’s not a good idea to use plumbing solder for electrical connections because the acid in the flux can damage the wiring and lead to connection failure.

Do you need flux with acid core solder?

Acid Core Solder contains flux, however additional flux may be necessary to ensure proper flow of solder wire.

How long do you wait after sweating copper pipe?

Be sure to wait until the solder has cooled (2-3 minutes) before pressurizing the line to avoid the solder cracking due to a quick change in temperature.

Why does my solder not stick?

A classic reason solder won’t stick to something is because you’re not getting it hot enough. My interns come to me with this problem all the time. Make sure the tip of the iron is nice and shiny. Touch some solder on it, and it should melt almost instantly.

How do you know if your solder joints are good?

A good solder joint should have an even band of solder showing all the way around. If you see an area that looks as if it needs more solder, brush a little flux onto the joint. If the joint is still warm, the flux will melt and flow into the void.

Can you solder over old solder?

Just heat the joint up with your torch, once the solder starts to melt use Channel locks to pull the fittings apart. Once the joint is apart, wipe as much old solder off as you can with a rag. Now you can start over.

How can soldering defects be prevented?

The best practice is to be use solder conservatively and, if necessary, add more if the joint needs it. Strive for a clean solder with a nice concave fillet. Cold joints occur when the soldering iron is at a lower-than-optimal temperature, or the duration of the heating of the joint was too short.