Why Solder Is Not Sticking To The Copper Pipe

Why Solder is Not Sticking to the Copper Pipe: What to Do!


Its really gets annoying when you are trying to fix a joint, and the solder is not sticking. But for homeowners like us, it’s also common. Before getting into the solution, we need to find the reason behind not sticking. 

The only curiosity in our mind is why solder is not sticking to the copper pipe. 

The most common reason behind this issue is the heat. If your solder is not hot enough, it will not stick. The solder will easily come off if it’s oxidized. So, remove the air bubbles and make the solder hot enough. Besides, dirty working materials will prevent the solder from sticking. 

Well, that’s just the sneak peek of what you’re about to get. So just hold on tight, and go along with us to stick the solder properly. 

Why Solder is Not Sticking To The Copper Pipe: 4 Surprising Reasons

Soldering is an incredible process if you are to join to pipes. Specifically for copper pipes soldering is really necessary.

But we might face issues if the solder we are using is not sticking well. Sometimes it doesn’t stick at all. 

The reasons might be pretty surprising to you if you are a new builder or homeowner. 

So, let us dig deeper into this and unravel the reasons we are waiting for! Let us go.

Reason & Solution 1 of 4: The Solder is Not Hot Enough 

This is one of the classic reasons everyone faced. If you are a beginner it’s very normal to face this.

Now, soldering is a process of heating and a hot iron. So you have to go through the heating process to make the solder melt.

We need to keep in mind that solder is just a metal alloy filter. So all we need to do is to heat the filter properly. 

So, if there is a heating problem in solder, we can solve it easily!

First and foremost, make the tip of the iron nice and shiny. You need t clean and wash the iron properly before heating.

Now make sure the iron and the solder are dry enough. The melting process requires patience.

So, we need to heat the iron properly when it’s dry. Then start melting the solder. 

Did you turn off all the power before heating? Make sure you already did the main disconnect or the service one. Turning these on while heating might be dangerous. 

The solder might not start melting right away. But you should constantly keep heating the solder.

If this method did not help you, there might be air in the solder.

Reason & Solution 2 of 4: Oxidized Solder

Heres is another common issue with solder. The solder you are using might be oxidized.

So, we need to understand what is oxidized solder! In a simple manner, the solder has small air bubbles in it.

However, these bubbles stop you from melting the solder. Trust me, we know how annoying this oxidized solder is!

So we have come up with a great solution. Firstly, we need to heat up the iron. But keep in mind that the temperature should be around 290 to 312 degrees Celsius.

Done heating up the iron? Now we need to add a flux-colored solder. That solder should be perfectly filtered and heated.

As a result, you will notice a chemical reaction on the solder. This reaction will help the solder to get rid of any air bubbles.

No matter what kind of oxidization you are dealing with, this will probably help your solder. 

But if the iron or the solder is somehow dirty, you are going to face issues with the melting.

Reason & Solution 3 of 4: Dirty Soldering Items

Soldering process should maintain a standard level of cleanliness. So that the solder melts and sticks very easily. 

Keep in mind that, we don’t only need the iron tip to be clean but also the other working material. For instance, you need to clean the soldering iron as well as the copper parts.

Because if you are not keeping one material clean, the process is not going to work.

However, if something comes up in the middle of this process, cover the clean area with something. You can use duct tape, 6 inches or 8 inches depending on your copper pipe.

To clean the soldering items, you need a strong flux. Don’t let air get into the solder. 

As soon as you get with the cleaning, just start the process.

If we are late, the solder might be exposed and it can get dirty. 

Reason & Solution 4 of 4: The Iron is Not Hot Enough

As we have already mentioned if the solder is not hot enough it will not melt. Eventually, it will not stick.

This whole process needs the materials to be hot enough for every step. If the solder is hot but the iron is not, we will face issues. 

Because the iron will stop the solder from melting, and eventually the solder won’t stick to the copper pipes. 

So, when you notice the solder is not sticking, it’s your job to check the wattage.

Double check, and compare both solder material and the soldering iron wattage. 

If you feel like the iron is not doing the job, you should replace it with a new one.

As a matter of fact, we have some amazing soldering iron listed for you! Check them out!

Product 1
Product 2

Some Soldering Tips You Need to Know!

Well, soldering copper pipes is not a hard job. But the process requires some perfectly measured job.

The first factor that bothers us, is the perfect temperature. So, we suggest you use MAPP gas. It will speed up the heating process.

And you always should use a flame protector. It will save you from any hazardous situation.

For copper pipes, always try to replace old fittings. Soldering new copper fittings are better. As they won’t have any leaks.

We should not use excess solder. Because it can break loose and damage your copper pipes.

And make sure the copper pipes are dry before the soldering process.

Finally, for safety reasons make sure you are wearing gloves and goggles. And make sure you are using the heat cautiously.

Well, that’s all you needed today!


Do I need flux for soldering?

Yes, you need flux for soldering.  If you don’t use enough or no flux there will be a cold solder joint. So you might face problems with the copper sticking. Even if the copper sticks it will not have wicked into the sweat joints correctly. 

Is it possible to overheat the copper pipe?

Yes, it is. Overheating is a great problem when it comes to soldering copper pipes. If you overheat the pipe, the flux will start burning. It means it will start oxidizing. As a result, the soldering process will stop working. 

What is an alternative for flax?

Although we always suggest you use flux, and not go for any alternatives. But if you have no other option you can go for petroleum jelly. It can wax the mineral water and make it an antioxidant.


Well, now you know all about why the solder is not sticking to the copper pipe. So, take your working materials and start the soldering process right now!

Make sure you are safe enough from the fire and keep a fire extinguisher by your side!

Leave us with any comments!

Onblissstreet is reader-supported. We may earn a commission through products purchased using links on this page.

Leave a Comment

Your email address will not be published. Required fields are marked *

Scroll to Top