You want to join two copper pipes or fix a damaged one and are wondering what kind of soldering flux to use. After all, there are hundreds of flux options available for you. But as any plumber will tell you, not all solders are ideal for copper pipes.
Thus if you want to ensure the joint stays leak-free for many years, you will want to invest in the best flux for copper pipes. Having worked in the plumbing business for close to ten years, we know a thing or two about soldering flux for copper pipes.
And using our experience, we have created a list of the five best soldering flux for copper pipes you can buy. We have also included a guide on choosing the right solder flux for you.
The number one spot goes to the Oatey Company 30374 1.7 Oz #95 Flux; it is incredibly easy to use and is laced with silver particles that will help make your connection stronger.
Second place goes to the Thermaltronics TMT-TC-2 Lead-Free Tip Tinner. This is an excellent flux that helps clean iron tips and prevents oxidation.
Today’s best Soldering flux
Reviews Of The best flux for copper pipes
Oatey Company 30374 1.7 Oz #95 Flux
The Oatey Company 30374 1.7 ounce flux is great for large diameter copper pipes. It is a tinning flux laced with silver particles. These particles will fill small gaps in the joint if your soldering is not perfect.
It is also water-soluble and helps remove dirt, surface oxidation, and other impurities from the surface of the copper pipe.
What I liked
- It is safe for use in copper pipes used for drinking water
- Contain silver particles that can fill up small gaps in the joint
Drawback
- It is pretty stiff out of the box, making it hard to apply.
If copper pipe soldering is not your forte, you will want this solder with its silver particles. It will help strengthen your joints and connections even if you do not do a perfect solder.
Thermaltronics TMT-TC-2 Lead Free Tip Tinner
Cleaning the soldering iron tip can be a pain in the ass. Luckily, it is less of a hassle with the Thermaltronics TMT-TC-2 lead-free tip tinner. This flux is designed to re-tin oxidized tips to make your work easier.
It will be an ideal choice if you have trouble soldering. Stick a heated iron tip into the paste, and it will coat the iron tip giving it a silver sheen. It makes the iron tip easier to use and easier to clean.
What I liked
- It is great for re-tinning oxidized iron tips
- It is lead-free and thus safe to use
Drawback
- You will need to heat the iron tip at temperatures above 250 deg to get this flux to melt and coat the tip.
This will be an excellent option for people who are new to soldering. It makes the soldering process easier and helps prolong the shelf life of your solder iron tip.
Chip Quik CQ4LF Liquid Flux No-Clean in 10ml
This Chip Quick CQ4LF liquid flux is a versatile flux used for both lead and non-lead applications. And unlike the others on the list, it is in liquid form. It is packaged in a flux pen with the liquid flowing out of the tip.
It is easy to use and comes with an extra felt replacement tip. It helps the solder stick to the joint better and can be used for tinning.
What I liked
- It comes in a great form factor that makes it easy to use
- It can be used for both lead and non-lead applications
Drawback
- The tip wears out quickly
This is a great flux for smaller pipes. And if you are searching for a liquid-based flux, this will be a good option.
2 Jar Solder Flux, Flux for Soldering, Rosin Soldering Flux
Designed for lead-free soldering, this Romeda 2 jar solder flux is a rosin core flux that will not corrode your pipes. This is great if you need to leave it on. It also protects against oxidation of the iron tip.
This two jar paste will be sufficient for several use cases. Also, this is more like wax than a solid paste, and it is easier to control how much you are using.
What I liked
- It is sufficient for use in different applications
- It is perfect for lead-free applications
Drawback
- Because of its wax-like nature, it can be a bit difficult to use
This flux is fantastic for cleaning iron tips. So if you have trouble cleaning the iron tip while soldering, this will be the best soldering flux for you.
No Clean Tacky Soldering Flux 5 Grams
Packaged in a syringe, the No Clean tacky soldering flux from 247 solders is one of the best flux for SMD soldering. The syringe makes it easy to apply the flux where it is needed. Also, this flux helps the solder flow easily.
Thus you will have an easier time soldering using this flux than without. It also works well on lead-free applications.
What I liked
- It comes in a syringe which makes it easy to apply
- It can be used with both lead and no-lead solder
Drawback
- The flux leaves a thick sticky residue which can be challenging to clean
Being able to easily add flux to a joint will make a world of difference. Thus the fact that this is packaged in a syringe makes it ideal if you want a flux that is easy to apply.
best flux for copper pipe buying guide
Which is the best flux for soldering copper pipe? More importantly, what is the characteristics of the best flux for copper pipe? To pick the proper flux for copper pipes, you need to know what to consider when buying flux for soldering copper pipes.
Amount or weight
How much flux you need will depend on the use case. If you are a professional plumber, then buying flux in larger amounts will be more feasible. However, if you are buying flux for the occasional DIY repair works purchasing a small amount of it will make more sense.
Some fluxes have shelf lives of two or fewer weeks, and thus buying a significant amount will be a waste if you are a DIYer.
Water-soluble or petroleum
Some fluxes contain petroleum-based products, while others are water-soluble and do not contain any petroleum products. You need to avoid flux with petroleum products for copper pipes as they are toxic.
Also, health regulations in most parts outlaw the use of petroleum-based flux in copper pipes used in plumbing.
RoHS regulation
Speaking of regulations, check to see if the flux you are buying is RoHS compliant. The Restriction of Hazardous Substances or RoHS directive outlaws the use of certain hazardous materials. Thus, a RoHs complaint flux does not contain hazardous materials that may be harmful to your health.
Liquid vs. paste flux
Flux can either be in liquid or paste form. Paste flux tends to have a higher melting point than liquid ones. Therefore they are used in the soldering of copper pipes where higher temperatures are used. Liquid flux tends to be used more in repairing electronics such as circuit boards.
Frequently Asked Questions
What is the best plumbers flux?
For copper pipes, a water-based flux is recommended in most parts. However, an acid-based flux may be a better option than a tinning flux.
Why Do you use flux when soldering copper pipes?
Flux is used to clean the copper pipe surface; more importantly, it is crucial as it draws in the molten solder deep into the cracks of the joint, forming a water-tight joint.
Why is too much flux bad?
Applying too much flux on the copper pipes will lead to it corroding the pipes over time. And in some cases, the excess flux will be pushed through the pipes and corrode other things.
How long does it take for flux to corrode copper?
On average, it will take the flux a week or two to corrode the copper pipe.
How long can flux sit before soldering?
Flux will, on average have a shelf life of two days before being used for soldering.
How do you clean flux residue after soldering copper pipe?
A water-saturated rag can clean flux residue after soldering copper pipe.
What Type of serious risks can cause for using the wrong type of flux?
Using the wrong flux will result in serious health risks. Using petroleum-based flux, for example, will accelerate corrosion of the copper pipes. This will result in a higher than the recommended deposit of copper in your drinking water.
Also, it will lead to bacteria contamination of the water higher than what is observed in most buildings.
Conclusion
Using flux to solder copper pipes will make your work easy. However, not all fluxes can be used on copper pipes. Some contain toxic chemicals that have been proven to be harmful to humans.
Thus it is essential to check the Type of flux you are buying for soldering copper pipes. Ultimately, the best flux for a copper pipe that will help clean the pipe surface and prevent oxidation of the iron tip.
Last update on 2024-11-20 / Affiliate links / Images from Amazon Product Advertising API
