Best Soldering Flux For Electronics : Expert Reviews And Buyer’s Guide

Soldering Flux

The aim of this review is to provide you with the best soldering flux, which we decided on after reviewing ten of the most popular soldering fluxes available to buy. These ten fluxes were compared to each other to decide upon the one that offers the best all round performance for people. The advantages and the disadvantages of using each of the products are considered to assist in making the decision over, which flux was the best one to use over all. There will be a brief summary of why the winning soldering flux was chosen.

#1. Rosin Paste Flux Jar # 135 in a 2 oz jar

The SRA # 135 is a reliable Rosin flux paste sold in a 2 oz jar that is best used for soldering electronic items. It is a durable flux that can survive extreme temperatures.


  • This product is supplied in a 2 oz jar shaped like a hockey puck.
  • This rosin paste does not contain either Zinc Chloride or Ammonium Chloride making it great to use for the repair of electrical items.
  • The SRA rosin coats the soldered area to help protect it from rust. That means having extra residue left on the soldered parts is not a problem at all.


  • This paste can be used effectively in a 93 to 315 degrees C temperature range
  • It bonds the parts tightly to each other
  • The rosin can prevent rust


  • If stored too long it can dry out
  • Dipping the soldering iron or other things into the paste may not put on the right amount of flux

#2. LA-CO Regular Soldering Flux Paste 2 oz

The LA-CO Regular Soldering Flux Paste is sold in a 2 oz bottle, and is a reliabe paste that is non -toxic and does not contain Zinc Chloride. A good all weather flux paste, good value for money.


  • There is less need to worry about the risk of rust as it does not contain Zinc Chloride.
  • This flux is water soluble meaning that no residue is left in water piping.
  • It is a safe product to work with as the formula is lead free, acid free and non - toxic.


  • All weather paste means that it can used for items used indoors and outdoors at any time of the year
  • This product meets standard ASTM B813
  • This flux causes no pollution and leaves no waste
  • It cleans it's own pipes


  • This product is not spplied with a brush
  • May turn black if it gets too hot

#3. MG Chemicals 8341 No Clean Flux Paste 10 ml Pnrumatic Dispenser

The MG Chemicals 8341 No Clean Flux Paste in a 10 ml Pnrumatic Dispenser is a paste decided to aid soldering when higher levels of precision are required. To get the best out of this dispenser carefully follow the instructions and take a note of the disadvantages mentioned.


  • This dispenser comes complete with a plunger as well as a dispensing tip
  • The easy to use plunger system means that no clean is needed after use.
  • Flux paste sets exactly where you want it to after applying it.


  • Any residue left does not need cleaning as it will not has any affect on the surfaces it is on
  • It precisely places the paste on the required surfaces


  • The syringe can be stiff and therefore difficult to use
  • It is hard to put the paste where it needs to go
  • Still need to clean up excess paste from surfaces
  • The paste does not work if the soldering iron is too hot

#4. SRA # 312 Soldering Flux Pen Low Solids No Clean 10 ml Refillable

The SRA # 312 Soldering Flux Pen Low Solids No Clean 10 ml Refillable is a pen full of flux that is mainly intended for reworks. Not really suitably for heavy duty soldering but it does a decent job for reworks or a temporary fix.


  • This pen is suitable for networking and touching up of through the hole solder joints plus SMT and SMD
  • The refillable pen can be used for cars, computing repairs and telecom.
  • Each pack contains 10 ml No Clean Low Soilds flux that is long lasting and refillable.


  • An environmentally friendly product
  • Can be used with lead and lead free soldering irons
  • The pen does not leak flux
  • The flux paste is easy to apply
  • Effective product to use with circuit boards


  • The pen is not so effective on surfaces where oxidization has already taken place
  • A brush applicator would work better on uneven surfaces

#5. MG Chemicals Liquid Rosin Flux 125 ml bottle

The MG Chemicals Liquid Rosin Flux 125 ml bottle is a liquid flux that is really sticky stuff. A good all round flux for soldering, bonds extremely well yet apply with precision as it is hard work to clean away excess amounts.


  • This rosin liquid can be used with lead and lead free soldering irons.
  • It is a fast wetting and quick working flux formula.
  • The flux has a non - corrosive formula to reduce the risk of rust on any soldered surfaces.


  • The lead free formula makes the rosin RoHS compliant
  • The flux is an easy pour liquid
  • It is very sticky so things stay in place once it has set, and often small amounts will get the job done
  • Can use indoors or outdoors


  • It is difficult to remove when set and an alchol based cleaner is required to do so
  • Remember to apply in small amounts to avoid having to clean it up
  • You need to be precise when applying it because it is difficult to remove excess residues

How to choose the best soldering flux for electronics

Although a best over all soldering flux has been decided upon, all of the ten products used have times or circumstances when they are the better type of flux to be used. The winner was selected by comparing all the uses and deciding, which one has the most notable advantages and the least important disadvantages. Flux when used as it should be makes soldering more effective, making the bond between two surfaces more secure. Users will opt to use different types of flux depending on what surfaces they need to bond to each other. Some of the products are general flux pastes, whilst others are designed for more specific types of soldering.

Flux pastes are not all the same and buyers need to have in mind the tasks that the flux needs to perform, before selecting the product that is most likely to meet ther needs.

Instructions should always be followed when using flux paste, and regular users often have brushes, syringes and even disposable gloves in order to achieve the best use out of flux pastes. Having these other items to hand means it it is easier to apply flux, and often means there is less mess to clean up.


After reviewing the uses and the features of each product the judgement was made, and the verdict announced.

Product 8 was selected as the best soldering flux. It was decided that Product 8 was the best performing flux for Soldering Electronics, with it's advantages easily outweighing it's disadvantages.

We were highly impressed with the performance of the Haris SCLF16 as a soldering flux. When used as per the instructions supplied with it, it provides excellent performance as a best flux for soldering electronics.

Some of the other flux pastes reviewed are generally considered to be really effective yet we decided that their performance was not as good, had more disadvantages, or was not as effective over all as the Harris flux paste. We found that the 16 oz bottle makes it exceptional value for money and recommend people should use this product.

We concluded that the Harris flux can be relied upon to get the soldering jobs done, Even better there is no need to clean up after use. The Harris flux liquid will allow you to solder any surface, whilst It is particularly effective at soldering stainless steel to copper.

Richard William

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