Homemade Solder Flux: Cheap Eco-friendly Alternatives

We are well aware that soldering plays a pivotal role in various applications. The solder acts as filler metal in the procedure. Soldering flux is a kind of solution you can apply on the metal workpiece surface to clear any impurities and oxides. In this way, you’ll get smooth and full joints.

But these soldering fluxes are sometimes so expensive that most people can’t afford them. But still want to get clear and shiny joints so they can go for soldering flux alternatives. So if you’re looking for a cheap alternative to soldering flux, then this post is for you. Here we’ll tell you to create homemade solder flux.


Some soldering flux alternatives

If you’re a professional welder, you must understand which alternative to use in case the soldering flux ends up in the middle of the project. In that case, you don’t have the time to go to the shop and buy soldering flux. That’s why it is good to know which readily available you can use as an alternative. There are some soldering flux alternatives you can quickly get or prepare at home. Let’s have a look.

  • Petroleum Jelly

The first and foremost choice as an alternative for soldering flux is none other than petroleum jelly, as it has several uses due to its versatile nature. As a DIYer, you must have this product in your home because its wetting and cleansing characteristics are similar to commercial soldering flux.

You may be wondering what makes petroleum jelly so effective for use as a soldering flux. Basically, they are the constituents that make it an ideal replacement for commercial soldering flux. Moreover, petroleum jelly is made up of waxes and minerals that bestow anti-corrosion properties in it. So, it doesn’t harm the solder or the material you are going to apply the soldering technique to.

Other than that, petroleum jelly has an excellent cleansing effect which not only eliminates dirt and impurities from the surface of the metal workpieces but also removes metal oxides as well. In this way, it will help you create a stronger joint which otherwise wasn’t possible on a metal workpiece surface having metal oxides.

Those people who sometimes solder their household appliances such as TV, desktop, LED bulb, etc., can benefit from petroleum jelly. The fact is petroleum jelly costs incredibly lower as compared to commercial soldering flux. That’s why it suits DIYers. Further, it melts instantly from the heat of solder iron appropriate for use in many applications.

  • Lemon Juice

If you have a few lemons in your house, then you can cut them out and squeeze their drops. And collect these drops in a dish. These drops work adequately and have acidic flux properties ideal for removing dirt, impurities, and metal oxides.

Amazingly, the high content of citric acid eliminates metal workpiece oxides much better than commercial soldering flux and petroleum jelly. Using lemon juice all the time as a soldering flux can be expensive, but it’s an excellent substitute for soldering flux.

If you are doing soldering and flux ends up during the procedure, and you haven’t any time to go to market, then lemon juice is a perfect remedy. Moreover, the best part is you can store it for later use. And one thing you should avoid is not to put the juice in the refrigerator. Otherwise, it will not be as effective.

  • Pine Tar homemade flux

If your accommodation surrounds many pine trees, thank God because it’s the main ingredient in any soldering flux. You can develop a homemade flux by collecting the pinecones and then stoking them in a large bucket. Of course, once you have stored pine cones in the bucket, you now have to put a decent amount of alcohol over it.

Now, wait for a minimum of 10 to 12 hours to let the fluid inside the pine cone get mixed with the alcohol. After that, separate out the solution from the rest of the material, including leaves and other debris. This solution is now ready to be used as a homemade flux.

If you immediately want to create a homemade flux, then the time needed to create pine tar & alcohol flux may not suit you. But you can save a lot of money if you can make this homemade flux in case you have access to an abundance of pine cones. So, it’s better to make this flux before you need it.

  • Rosin homemade flux

Like pine tar alcohol flux, rosin’s homemade flux creation procedure is identical. A significant amount of rosin solution is necessary to create a homemade flux. You can have this product in your home if you are a sporty person because it is widely used in climbing and various sports as well.

Now step up the pieces of rosin in a bottle and then put upon it alcohol or another solvent such as nail polish remover.  It will dissolve the rosin in a short time. In case the pieces are large, then the procedure might take a long time. To cope up with big rosin parts, you can crush them beforehand. The homemade soldering flux will be ready to use once rosin gets dissolved.

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Is it possible to solder without soldering flux?

Absolutely it is possible to solder without applying flux on the metal surface. The only purpose of using flux is to break down any oxides and for wetting the metal to get a full and smooth weld. If the metal has any impurity on the metal’s surface, then the joint will be shallow, not as strong as the smoother one.

But you don’t always need a soldering flux to create aesthetic joints; rosin core solders are available in the market, which is famous for soldering electronic circuits. Moreover, these soldiers are excellent in those conditions where there is no way to clean flux residue.

So, it totally depends on the solder you have, whether you need a soldering flux or not. If the solder already has flux in its core, then you don’t need to buy soldering flux.


How to commercial flux substitute soldering?

  • Cleaning the metal workpiece surface

First of all, eliminate dirt and grim particles on the metal surface. Ensure that it’s dry before the procedure starts. If you’re manipulating petroleum jelly, then it will work as both cleanser and soldering flux at a time which is ideal. Gently massage a small quantity of petroleum jelly on the surface of a metal workpiece. After that wipe it off with the help of tissue paper.

  • Now apply soldering flux alternative

It’s time to apply the soldering flux substitute after clearing the surface of the metal workpiece. However, if you utilize the homemade liquid flux or lemon juice, press this liquid onto the surface several times with Q Tip or brush. But if you have used petroleum jelly as a cleanser, then you aren’t required to apply flux. Because it has already done the function of soldering flux.

  • Spread molten solder using soldering iron

You need to apply the molten solder with the help of hot soldering iron, which makes sure that the solder doesn’t get hard shortly. If you feel that the molten solder is not sticking at the metal surface, then it indicates that you need to reapply flux as impurities are still there. However, it shouldn’t have to happen unless you have used a very little quantity of flux on the first try.

  • Wait for the molten solder to get back to normal

As molten solder is usually very hot, it takes time to get back to normal temperature, so wait until then. After that, check whether the joint you have created is strong or not. The joint should have to be strong if you put on an appropriate amount of flux and haven’t sensed any difficulty performing the procedure.


We have disclosed some cheap and homemade alternatives to commercial soldering flux that work exceptionally. Moreover, if you’re a DIYer, these hacks are ideal for you because you can save your money using these soldering flux alternatives. However, some DIYers do soldering infrequently; that’s why buying a soldering flux is just a waste of money.

We hope you found our article on homemade solder flux beneficial. For any further questions comment below.