How to solder pipe

Introduction: How to Solder Copper Pipe

How to solder pipe

How to solder pipe

How to solder pipe

Last year I had a project that required several small copper pipe connections to be soldered. Having never sweated (don’t ask me why they call soldering that) copper pipes before, I read an article or two and then tried it for myself. My first attempts worked out quite well and I’ve since soldered a few more connections. While I don’t profess to be an expert in pipe sweating, I thought I would write a quick Instructable to pass along what I’ve learned in the hope that some of you may find it useful.

Step 1: Cut Your Pipe

The first step to assembling copper pipe is to cut your pipe to length. The easiest and best way to accomplish this is by using a tubing cutter. I’ve been using a small close quarters cutter, but there are larger cutters, which operate on the same principle. The operation of all of these cutters is similar. Once the cutter is placed around the pipe, it is tightened until the pipe is clamped between the cutting wheel and the two rollers used to support the pipe. The cutter should be tightened slightly past the point where the cutting wheel first begins to contact the pipe. Be careful not to over tighten as the copper pipe can easily be crushed. After tightening the cutter, it is rotated around the pipe several times until the tension on the cutting wheel begins to be released as a grove is cut into the pipe. By retightening the cutter and continuing to rotate it around the pipe, this grove will continue to deepen until it cuts completely through the pipe. If you’ve done everything correctly, you will have a neatly cut pipe. It is also good practice to remove the small lip on the inside of the pipe produced by the cutter wheel. While this lip may not pose an immediate problem, it can result in sediment accumulating in the pipe, which could eventually plug the pipe. Some larger tubing cutters have a built in deburring tool or you could use a purpose-build reamer to easily accomplish the same thing.

Step 2: Cleaning the Pipe and Fitting

Prepwork is critical to ensuring a good soldered joint and cleaning of the copper is the first step. I’ve used several tools and methods for cleaning both the pipe and fitting. One method is to use a wire-based tool, such as the cleaner I use to clean the outside of the pipe in the image above. Small wire bristles inside of this tool scrape away the oxide layer on the outside surface of the pipe until it is nice and shiny. There are also wire tools available to cleaning the insides of fittings.

An alternative method for cleaning the pipe and/or fittings is to use emery cloth. To clean the insides of the fittings I rolled the emery cloth into a small cylinder. By rotating this cylinder inside of the fitting, it was quickly cleaned.

Step 3: Flux It

The second critical preparation step is the application of flux to the joint. Since the solder cannot be applied directly inside the joint, the flux will “pull” the solder into the joint, making a strong, sealed connection between the pipe and fitting. Without flux, the solder can only form a superficial layer at the entrance of the joint and even if it initially does not leak it won’t hold up long. I apply a liberal layer of flux to both the inside of the fitting and the outside of the pipe before sliding the two parts together.

Step 4: Heat It

Soldering copper pipe requires a relatively large amount of high intensity heat, which is why a propane torch is typically used to heat the joint. You can’t use a soldering iron here. The heat should be applied as evenly as possible around the fitting. The amount of heat needing to be applied will vary, but we’ll deal with that in the next step.

Step 5: Solder It

As I heat the joint, every few seconds I will remove the heat and touch the tip of my solder to the joint to see if the metal is hot enough to melt the solder. If it does not melt or only slightly melts, I remove the solder and continue to heat until the solder easily melts onto the copper. Once the solder easily melts onto the joint, I apply enough solder to fill the joint and then re-heat the fitting, which draws the solder into the joint. You’ll know you have applied enough solder when there is a silver band the entire way around the joint. When this band is flush with the surface of the pipe, you’ll know that solder has been drawn into the joint. If you apply too much solder, a small solder bubble will form on the lower side of the joint. This does not affect the integrity of the joint, but can look a bit messy. Also note that excess solder can flow into the inside of the pipe, which can interfere with flow through the pipe if the quantity of this solder is large.

At this point you have completed your joint and can simply clean away any flux remaining on the joint. However, if you stick with me I’ll give you two other tips I’ve learned.

Step 6: Re-soldering a Joint

If you’re new at this you’ll most likely need to re-solder a joint at some point. You can easily disassemble a soldered joint by heating the joint and pulling it apart using a pair of pliers. Once you’ve disassemble the joint, you’ll most likely find it impossible to reassemble as the solder will prevent the two parts from sliding together. There are two ways around this. First, you can heat the joint until the solder softens and then reassemble it. While this can sometimes work, it is a bit tricky as you have to reassemble hot parts. A neater method I’ve found is to sand the outside of the pipe and inside of the fitting with emery cloth, which quickly removes most of the soft solder. With this solder removed, the parts can be re-fluxed, slid together, and re-soldered.

Step 7: Supporting Joints

Fittings with multiple joints (such as a T-fitting) can be tricky to solder together as the heat intended for one joint can easily soften the solder of the adjacent joint. While this isn’t necessarily a problem, if the adjacent joint is situated such that gravity will pull it apart, it can easily fall apart. To prevent this from happening, I always position the joint(s) adjacent to the one being soldered in a horizontal position.

Step 8: You’re Done

I’ve found soldering copper to be very rewarding and useful for numerous projects. It really isn’t very difficult and it will open up numerous possibilities in your mind of what can be accomplished using this skill. Happy making!

* Note that all amazon links are to my affiliate account. I receive a small commission and you pay the same price. Thanks!

Skill Level

Start to Finish


  • propane torch
  • paintbrush
  • emery cloth


  • copper pipes and fittings
  • flux
  • acid core solder
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Step 1

How to solder pipe

make sure pipe connection area is cleaned

Photo by: Cary Wiedman

Clean the Pipe

Use emery cloth to clean the outside of the pipe where the connection will be made.

Use emery cloth or a small wire brush to clean the inside of the fitting to be soldered onto the pipe.

Step 2

How to solder pipe

How to solder pipe

flux used inside fittings

Photo By: Cary Wiedman

secure the fitting to the pipe

Photo By: Cary Wiedman

Secure the Fitting

Use a small paintbrush to apply flux to the inside of the fitting (Image 1).

Secure the fitting to the pipe (Image 2).

Step 3

How to solder pipe

How to solder pipe

torch used to heat fitting

Photo By: Cary Wiedman

solder melts right into joint

Photo By: Cary Wiedman

Heat the Fitting

Use the torch to heat the outside of the fitting (Image 1).
Touch the tip of the solder to the joint of the pipe and its fitting (Image 2). The solder will melt right into the joint.

After the solder has cooled, wipe away any excess, making sure that solder completely encircles the joint, with no gaps.

Skill Level

Start to Finish


  • brush
  • propane torch
  • wet cloth
  • safety glasses


  • soldering wire
  • copper pipes and fittings
  • flux
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Step 1

How to solder pipe

clean and apply flux to pipe

Clean and Apply Flux

Copper pipe needs to be cleaned before it can be soldered. First, use sandpaper to clean the inside and outside of the pipes and fittings that will be joined.

Next, use flux to remove impurities from the inner and outer surfaces of both pipes. Spread the flux over the entire surface with a brush. Then, slide the two pieces together.

Step 2

How to solder pipe

solder the joint

Solder the Joint

While wearing safety glasses, fire up the propane torch. All three parts of the flame should be blue; if the flame is orange, turn gas down.

Hold the flame on the tip of pipe to heat. The flux will turn to liquid and the pipe will change color slightly. When the pipe is heated, touch the soldering wire to the joint. If done correctly, the solder will be drawn into the joint.

Once the joint is soldered, use a wet cloth to clean up the area.

If you have a copper pipe that needs a soldered, you may have trouble keeping the moisture out. Moisture and solder do not mix well. Solder can only be applied to a dry pipe and soldering a wet copper pipe is made easy with a few simple preparations.

Step 1 – Shut Off Water

Find the main water valve in your house and shut it off. The main water valve is located by the water meter which is usually outside the house. Turn the valve until it stops.

Fill a bucket with water and put a shop rag in it. You should also have a fire extinguisher within reach. You will be working with fire possibly directly under wooden rafters. If a fire starts, use the bucket of water first to attempt to put it out. However, if that doesn’t work, use the extinguisher. You need to wear your safety glasses because if too much solder is applied, it can splash. Keep your eyes safe, especially if you are working above eye level.

Step 2 – Stop Moisture

Plumbers Bread is a cornstarch based moisture stopper. It will stop the moisture in the pipe and dissolve when the water flow is turned back on. Follow the directions on the Plumbers Bread closely and put it in the side of the pipe the leak is coming from or all the pipes that will be connected to the fitting.

Step 3 – Prepare the Pipe and Fitting

There should be no sharp edges. Cut sandpaper into a 1-inch strip and sand the ends of the cut pipe until it is polished and shiny. Make sure to sand all the way around and apply a thin coat of flux using an application brush to the outside of the pipe ends and inside of fitting. A thin layer of flux will prevent oxidation but too much flux will cause oxidation. Wear gloves when using flux because the chemicals in flux can damage your skin and eyes.

Step 4 – Place Fitting

Assemble the fitting onto the pipes and make sure it is tight.

Light the torch. Start on a low flame, then increase the size of the flame. Apply heat to the joint and move the flame around the joint consistently to evenly heat the fitting.

Step 5 – Solder the Joint

Once the joint starts to become a greenish color, test the temperature by touching the end of your solder to the joint. If the solder melts, it is ready to be applied. You can either apply the tip of the solder to the top of the joint and allow the solder to melt and flow around the seam of the joint or you can wrap the solder around the seam and let it melt.

Next wring out the shop rag in the bucket and gently wipe the joint so the solder is smooth. Take special caution not to move the joint while gently wiping.

The line of MAKERX crafting tools can do a lot to open up the possibilities for home craft projects. Among those tools, you have the MAKERX Wood & Metal Crafter . With its micro-ergonomic design and precise temperature control, this tool is great for pyrography projects.

Beyond its use for wood crafting, it can also function as a soldering tool that works great for repairing electronics, soldering copper, and much more.

With the ability to solder copper pipe, this tool can be used for a range of home DIY and repair projects . It can be used to repair pipes that are damaged or leaking, or you can use it to add new lines if you are doing a home remodel. In this post, we are going to teach you how to solder copper pipe using the MAKERX Wood & Metal Crafter with soldering capabilities.

Cutting the Copper Pipe

Many of these soldering projects will require you to measure and cut a length of copper pipe. The MAKERX Angle Grinder is a great tool for cutting copper pipe, which is powered by the MAKERX Hub that also powers the Wood & Metal Crafter and all crafting tools on the MAKERX platform. Additionally, you can use an autocut pipe slicer, tube cutter, or hacksaw to cut copper pipe .

To cut the copper pipe with an angle grinder, start by measuring and marking the location of the cut. With the pipe marked, secure it in a vise with the mark about 5-6 inches beyond the end of the vise. Turn on the angle grinder, and firmly place the spinning grinding disc on the mark, applying pressure into the pipe to create a groove. From there, continue to apply pressure on the angle grinder as it cuts through the copper pipe until finished.

Preparing the Copper Pipe

Cleaning the pipe and the fittings is an important part of getting a good seal when soldering copper pipe. Start by cleaning the end of the pipe that will go into the fitting using a sandpaper emery cloth. It should be cleaned until it has a nice shine on the surface. After that, clean the inside of the coupling using a wire brush.

Once you have the copper pipes cleaned, you need to apply plumbing flux to the surfaces that are to be joined. Brush an even layer of flux over the copper pipe end that is to go into the fitting. Follow that by applying flux to the interior of the fitting. With flux applied to the copper pipe and fitting, you can push the pipe into the fitting. Wipe off any excess flux from the joint.

Heating the Joint and Soldering the Copper Pipe

Unlike most soldering irons, the MAKERX Wood & Metal Crafter has a torch feature that makes it good for soldering projects like joining copper pipe. Using the torch setting on the tool, you can now start heating the joint. It is important to heat the entire joint evenly to apply the solder.

Once the joint is heated, you can hold the solder to the joint on the opposite side from the soldering tool. If the joint is properly heated, the solder should melt and flow into the joint. Work your way around the joint until you have an even silver band going around to form a seal.

Learning how to solder copper pipe does take time. If it is your first attempt, you might not get a perfect seal on your first try. Just take your time and make sure you do it right. Along with that, you should follow the best practices for soldering safety .

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“The biggest mistake a rookie makes soldering copper is they allow the heat of the torch to melt the solder. Do NOT do that.”

How to Solder Copper Pipe Checklist

  • The copper tubing and fittings must be clean
  • Stir up the flux paste
  • Use lead-free solder
  • Copper must be heated so it melts the solder NOT the torch flame
  • Watch the following video:

How To Solder Copper Pipe – MOST IMPORTANT TIP OF ALL

The biggest mistake a rookie makes soldering copper is they allow the heat of the torch to melt the solder. Do NOT do that. You must heat the copper tubing and fitting for about ten or fifteen seconds before touching the solder wire to the hot copper.

The HOT copper will melt the solder, not the torch.

To solder copper pipe you must heat the copper pipe and the fitting to be soldered to a sufficient temperature. When the copper is hot enough, it will actually draw the solder into the joint by capillary attraction. Believe it or not, the solder will actually flow uphill.

What is the Best Torch to Use?

A simple propane torch that uses screw-on bottles will adequately solder pipe up to 3/4 inch in diameter.

This is a great torch kit. This one is MAP gas which burns hotter than propane. A regular propane tank will fit the torch. CLICK HERE or the photo to have this delivered to your home in days. WATCH the video of it below.

Plumbers generally use acetylene torches for two reasons. The acetylene burns hotter than propane allowing for faster solder times. The acetylene is available in larger tanks which attach to handy hoses and lightweight torches. If you want acetylene, you just need to go to a large plumbing supply house or a place that services welders.

What Types of Solder Can I Buy?

Solder, which is available in leaded and no-lead versions, attaches to the pipe on a molecular level.

This is solder that has a 50 percent lead content. Look at the numbers on the end of the spool. Do NOT use this solder for water pipes for drinking water. CLICK THIS PHOTO to buy the solder for use in leaded glass, soldering wires, and other projects.

This is lead-free solder. Use THIS SOLDER for a copper pipe that drinking water passes through. CLICK THE PHOTO NOW to have it delivered to your home in days.

How Does Solder Work?

Solder works by bonding to the copper pipe when it’s heated. It’s very similar to how two pieces of steel get welded together.

The surface of the soldered joint actually becomes an alloy where the copper and solder intermix.

Why Does the Copper Need to Be Clean?

The copper pipe needs to be clean so the atoms of copper can easily bond with the atoms of molten solder. The solder WILL NOT BOND if the copper is oxidized or dirty.

For this to happen, the copper must be very clean and free of oxidation. You can clean copper pipe in any number of ways. You can use coarse steel wool, sandpaper and/or a wire brush. Special round wire brushes come in a variety of sizes to clean the inside of copper fittings and valves. Simply twist the brushes or pipe to clean them. Even if you purchase a new copper pipe, it should also be cleaned. You only need to brighten the area which is to receive solder.

Why Do I Need to Use Flux?

Flux is a chemical which helps you solder. Flux prevents the copper from oxidizing as you heat the copper with the torch.

It actually finishes up the cleaning job you started with the sandpaper and brushes. In addition, it prevents the pipe from oxidizing as you heat it. 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. Besides, once you start to heat the pipe, 90 percent of it boils off and evaporates.

What are the Different Types of Solder?

Solder is available in generally three types: 50 percent lead/50 percent tin; 95 percent tin-antimony/5 percent lead; and lead-free solder.

Any water supply pipe should be soldered with solder that contains no more than 5 percent lead. If possible, use the lead-free solder. The 50 percent lead solder is used for copper drain lines. It melts at a lower temperature and is able to bridge larger gaps as it cools. This is handy when working with large diameter (up to 4 inches!) copper pipe and fittings. You MUST pay attention when you buy solder. The 1 pound rolls look very much alike. Carefully look at the label as you might purchase the wrong one.

How Do You Light a Torch?

Plumbing torches can be lit with matches, lighters or preferably a flint striker. Some torches have built-in igniters. Watch this video:

CLICK HERE to purchase the torch you see me use in the above video.

Matches and lighters can be dangerous, as you might not put them out. A flint striker makes sparks which ignite the flame. Plus, a single flint in a striker can last a homeowner 10 years or more! Flame temperature is important. You need to set the flame on medium or high to generate enough heat to melt solder. If your flame is adjusted correctly, it will burn different shades of blue. You will notice at the center of the flame a darker blue section that comes to a point. This is the hottest part of the flame. You apply this part of the flame to the copper pipe.

How Do I Heat the Copper Pipe?

Don’t be afraid to heat both sides of the pipe. Rotate the torch around the joint for even heat distribution. When I use my acetylene torch and I am soldering 1/2 inch pipe, I can usually heat the pipe to the correct temperature in 10 seconds or less. A propane torch may take 15 to 20 seconds.

How Do I Prevent a Fire When Using the Torch?

You prevent a fire by using a thin piece of sheet metal as a heat shield. Place the shield in between the copper tubing and anything flammable.

Always look beyond the pipe. Extremely hot temperatures extend out beyond the visible portions of the flame.

You can easily scorch lumber or wires. If you are soldering near old lumber or in joist spaces near vertical walls, you can start your house on fire easily. Be careful and use flame shields. These are flame resistant fabrics or simple pieces of sheet metal which absorb and/or deflect the heat.

Always have a 5-gallon bucket of water handy in case you do start a fire. If you have water still on in the house and can have a charged garden hose right next to you, that’s the best thing.

Click here to watch a video on soldering copper pipes and fittings.

How Do I Apply the Solder?

As you heat the pipe and fitting you will see the flux begin to boil and evaporate. Once the flux stops boiling the pipe is generally hot enough to solder. Move the torch away and touch the solder to the pipe.

It may take 2 to 3 seconds for the solder to melt. If the pipe is horizontal, apply the solder to the top of the pipe. The solder will roll around in an instant.

If you have done the job right, a droplet of solder will be at the bottom of the joint. You can flick this molten solder away with an old rag.

Blowing on the joint will allow it to cool. It will be hot, but rub the joint quickly with an old rag to remove flux residue. This will also polish the solder. Check the joint closely to see if you see a silver colored band around the entire joint. If so, your first solder joint may be perfect. As I would say on a job, “Another quality installation!”

How to solder pipe

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Soldering brass valves to copper plumbing pipes is easy if you do it right the first time, but it can be troublesome if you have to redo it. When the metal reaches the proper temperature, plumbing solder wicks into the joint between the pipe and the valve by capillary action and makes a watertight seal when it cools. If the pipe isn’t hot enough when you apply the solder, however, the joint will probably leak, and the remedy is usually disassembling and resoldering the joint. To avoid this, make sure moisture inside the pipe can escape when it turns to steam.

Turn off and make sure there is no water flowing inside any pipe before you attempt to solder a valve onto it. If you’re installing a valve onto an existing supply line, turn off the water to that line. If the line doesn’t yet have a dedicated valve, turn off the main water valve for the house.

Cut into an existing supply pipe with a pipe cutter. Put a bucket under it to catch water that will flow out once you’ve made the cut. Open any other faucets or valves connected to the pipe and wait for all the water to drain from the cut pipes. Leave the faucets and valves open while you solder on the new valve.

De-burr the ends of the pipes with a wire brush. Some pipe cutters have an attached brush for this purpose. If the copper has oxidized and turned black or green, use the brush to clean off the oxidation from the ends of the pipes and restore the natural shiny color.

Spread flux generously on the ends of the pipes and on the inlets of a brass valve with the brush that comes with the flux. If you’re installing an inline valve rather than a brass faucet, you may have to cut a small section from one of the pipes so you can fit the pipes back together with the valve in between them. If so, don’t forget to de-burr the newly cut pipe and brush oxidation off its surface before spreading flux.

Assemble the valve onto the pipes, being sure that at least 1/2 inch of pipe fits inside each valve inlet. Make sure the valve is open before you begin soldering.

Light a propane torch and adjust the flame until it is blue, pencil-thin and about 6 inches in length. Hold the tip of the torch about 2 inches from a joint and keep it there. When the metal reaches the right temperature, the flux will turn black and begin to bubble and smoke. At this point, remove the flame and touch the tip of a coil of lead-free solder to the joint.

Move the tip of the solder completely around the pipe as the solder melts and disappears inside the joint. Work quickly so that the metal doesn’t cool below the temperature needed to melt the solder before you’re done. If you’re soldering an inline valve, heat the other joint and apply solder in the same way.

Let the pipe cool, then turn on the water and inspect the joints for leaks with the valve in both the open and closed positions.

Introduction: How to Fix a Pinhole With Plumbing Solder

How to solder pipe

How to solder pipe

How to solder pipe

What’s up everybody, in today’s article I’ll be showing you if it possible to temporarily fix a pinhole in a copper water line by soldering it with normal plumbing solder.


Pinholes occur throughout the years where corrosion eats up the inside of the pipe just enough to make a small pinhole. You might not notice it right away, but pins holes can wreak havoc on any type of property as its silent killer.


So to start of the first thing to do is to shut off the water, the method I’ll be using necessitate that there is no water in the pipe.

Secondly, you’ll need a torch, some 50/50 solder and all that is required to complete a full solder.

The first step here is to clean the affected area with an emery cloth or sandpaper or else your solder won’t adhere properly.

Next, apply some flux to the repair area. Without flux, you won’t be able to make the repair so make sure you have some handy.

Once that’s done, it’s time to start soldering. Grab your torch and start heating the area. Don’t overheat as to not burn off all the flux, just enough so your solder will melt.

Now here comes the tricky part, you’ll have to heat up the pipe just enough so the solder melts, but not too much or the solder will just drip off.

The trick here is to use your torch to heat the pipe up at the right temperature, to do this, keep it close in the beginning and when the solder starts to melt remove the heat from the pipe and alternate just like this to keep the right heat on your work area.

When the gap is filled, wipe off any extra flux and inspect your work.

50/50 solder contains lead, so make sure you come back and fix this the correct way.


If you are hesitant, now is the good time to add into it seeing there’s no water in the pipe. If you feel comfortable turning the water back on, do so but do keep an eye to see if there are no leaks, and you’re done.

Of course, this is a temporary fix, you should use the proper coupling to permanently fix it but this could get you outta trouble if you don’t have the appropriate fitting at the right time for whatever reason.

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