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Copper To Brass Threaded Fittings [How To Solder It]

You’re about to install a copper inlet to your plumbing section. But it needs to go with a brass threaded fitting on the other part. Your plumbing experience says this is a new job for you.

How to connect copper to brass threaded fittings?

The copper inlet needs to be soldered with brass threaded fittings. To do so, polish the edge of the inlet that goes in the brass fitting first. Apply some tinning flux on both joining edges of the inlet & brass fitting afterward. Once done, join them together and solder them properly.

That was the whole process in a nutshell. But it isn’t enough to get the job done. We’ve explained the whole process in our piece here.

Are you curious? Let’s jump in then!

How To Join Copper To Brass Threaded Fittings?

Joining copper to brass threaded fittings requires quite a few tricks. You won’t need a professional to do the job right away. But we hope you have ideas about basic FPT in plumbing projects. It’ll give you ideas about male & female threaded edges.

A brass threaded fitting can have two types of the threaded end. It can be either a female threaded end or a male threaded end. The other edge of the brass gets connected with copper inlets. The inlet is joined through the soldering process. 

To join copper with a threaded brass fitting, you’ve to follow some steps. But you’re going to need these tools first to do the job-

  • Safety gloves
  • Copper inlet
  • 120-grit emery cloth
  • Circular wire brush
  • Propane torch
  • Tinning flux
  • Pipe cleaner
  • Solder
  • Teflon tapes

Got all you need? Let’s begin!

Step-1: Polish The Copper Inlet

Firstly, sand the edge of the copper inlet that’ll be attached with the brass. Use a 120-grit emery cloth to do the job. Keep sanding it until the edge gets shinner than other parts.

Take a circular wire brush now and insert it inside the copper inlet’s edge. Scrub the inlet thoroughly with the brush. Repeat the process a few times. Lastly, wipe the inlet with some abrasive cleaner to clean out any remaining dirt.

Step-2: Attach The Threaded Brass To The Inlet

Add a coat of tinning flux on the shiny edge of the copper inlet. Apply it both in the inside and outside area. Put on some tinning flux inside the threaded valve as well.

Join the copper inlet with the brass fitting now. Make sure it’s tightly fitted. Add some tinning flux outside the joining area too.

Step-3: Solder The Joint

It’s time to solder the joining point. Use the propane torch to heat the joining area of the brass and inlet. Heat the area for 30 seconds. Now, take 8 inches of solder from a solder roll. Bend it to 90 degrees and touch it to the seam.

If the solder melts easily, keep applying it around the joining areas. If it doesn’t melt properly, apply heat evenly to the same area again. This time heat it for 15 seconds and apply solder again. 

Keep applying heat every 15 seconds interval and solder the joint. Do this until the joint is properly soldered. The process is similar to soldering ball valves open or closed.

Step-4: Cool Down The Soldered Area

Take a wet rag and use it to wipe away the extra solder. Wait for 2-3 minutes. Once the time is up, dip the whole thing into normal temperature water. It will cool down instantly.

Step-5: Seal The Joint

It’s time to seal the other end of the brass threaded fitting. To seal it you’re gonna need some Teflon tapes. If the brass fitting’s end edge is male threaded, wrap the tape clockwise. Wrap it 2 to 3 times. 

If the edge is female threaded, the tape can’t be applied over the fittings. Instead, wrap the tape around the male threaded end of the appliance. Attach the brass fitting over the appliance and tighten the joint. It is now properly sealed.

What to Do If There’s A Leak In The Joint?

It’s common to face leaking problems in soldering. It happens due to poor soldering or bad sealing of the threaded end. If there’s a leak in the soldered joint, unfortunately, you’ll have to solder it again. 

Apply more solder to the area to seal the leaks. Just repeat the soldering process. But don’t apply too much solder either.

If the leak is in the sealed joint, the problem is within the sealing. The Teflon tape might have gone bad. In some cases, rather than tapes many use sealing compounds. 

After a certain time, this sealing compound also loses its efficiency. As a result, leaking issues arise.

To solve this problem, you’ve re-apply seals on the threaded joints. You’ll need waterproof tapes made out of Teflon or Delrin

But it’s best to use Teflon tape or any sealing compound for the sealing. If you’re looking for good sealing compounds here’s what we suggest-


A strong sealing compound like these will increase the longevity of your work. 

That’s it! Hopefully, the whole process is clear enough for you now.


Question: Does Teflon tape melt when soldering?

Answer: Yes, it melts when the soldering process takes place. Teflon tapes are sensitive to heat. It can melt at a slightly higher temperature. That’s why if you’ve soldered any metal with Teflon tapes on it, re-apply the tape.

Question: How to remove solder from brass?

Answer: Apply heat on the soldered area with a heating torch. Don’t overdo the heating. When the solder melts, wipe it with fine paper or steel wool.

Question: What is brass made of?

Answer: Brass is one kind of metal alloy made with a combination of zinc & copper. The amount of zinc & copper can vary. This variation makes the brass softer or harder.


That was all from us about copper to brass threaded fittings. Hopefully, you’ve found our piece helpful for your project. 

Lastly, good luck with your renovations!