Best Soldering Flux For Electronics

Hey are you looking for the best soldering flux but haven't a clue where to start? Okay, do not worry because you certainly aren't alone! The debate over which flux is recently the best on the market is a surprisingly ferocious one. Surely you'd expect there not to be too much difference between pastes and glues? Wrong!

Here part of the problem is that it depends considerably upon your own soldering style and of course what components you are dealing with. To make sure you end up with a suitable flux you need to think past the notion of it being a kind of 'metal glue'. Look instead for a clean product that is easy to apply, reliable, and ideally also non-acidic for an easier cleanup.

But as we shall see, there's a lot more to soldering flux than may meet the eye. We have selected five popular products to review for this purpose, so with an open mind and in no particular order, let's check them out.

Top 10 Best Soldering Flux For Electronics

1. SRA Soldering Products Rosin Paste Flux #135 In A 2 oz Jar

  • The ideal flux for electrical and electronic repairs
  • Formulated for use with tin/lead and lead-free alloys
  • Contains 2 ounce in a "Hockey puck" Jar

2. Kester 186 Liquid Soldering Flux, RMA Rosin, 2-ounce Bottle

  • High thermal stability for soldering multi-layer assemblies which require higher temperatures
  • Improves soldering performance
  • Eliminates the need and expense of cleaning

3. LA-CO 22101 Regular Soldering Flux Paste, 2 oz

  • Water-soluble paste won’t leave residue in water piping
  • Non-acid, non-toxic, and lead-free to eliminate safety concerns
  • All-weather formula for use in hot and cold climates

4. 2 Jar Solder Flux, Flux for Soldering, Rosin Soldering Flux Paste

  • Flux is suitable for welding instruments, gold, copper, tin, iron and other metals.
  • Anti-oxidation effect on soldering iron head of gold-copper alloy substrate.
  • Solder flux for semi-solid, not easy to dump.

5. No Clean Tacky Soldering Flux 5 Grams

  • The soldering flux comes with two tips.
  • Perfect for surface-mounted devices
  • Works great for cleaning circuits and tinning copper. Apply where it's needed.

6. MG Chemicals - 8341-10ML 8341 No Clean Flux Paste

  • Superior fluxing ability
  • Compatible with lead free and leaded solder systems
  • Instant wetting

7. MG Chemicals - 835-100ML Liquid Rosin Flux, for Leaded and Lead Free Solder

  • For leaded and lead-free solder
  • Non-corrosive
  • Non-hygroscopic

8. 60 ml. / 2 Oz. KESTER 951 No Clean Soldering Solder Liquid Flux Reflow

  • Great for all soldering needs
  • Tip is tethered, so you don't lose it.
  • Great alcohol-based flux

9. CAIG LABS RSF-R80-2 Rosin Flux Soldering 2094258 Paste Jar

  • Permits soldering of even difficult metals such as brass or Nickel
  • Can be removed with cloth or solvent
  • Non-spill consistency

10. ETEPON 959T Soldering Flux 2oz Bottle, No Clean Lead Free

  • Lead free - RoHS Compliant
  • Compatible with lead and lead-free solders
  • No clean formula- low solids content for low residue

Top reviews of the Best Soldering Flux For Electronics

#1

Delcast Rosin Soldering Flux Paste 50G

Now we'll start by taking a look at this popular - yet also quite polarizing - flux paste. This product is without any doubt a good all-rounder, being suitable for both leaded and lead-free purposes.

RoHS compliant and matching J-STD-004B requirements, you can at least be pretty certain not to be picking up a dud. While it performs pretty much as advertised there's a couple of things to be aware of.

First of all, this flux paste dries fast - sometimes too fast which means it is advisable to take it through a practice run before taking on a serious project. While this may take a little getting used to for those who are more used to gel-based flux, the final result is very impressive when care is taken.

The most significant issue is the pneumatic dispenser. Even halfway through the tube, you still need to allow for a 'suck back' when applying to control the speed it is dispensed at. Again - when you get used to it, that's fine but some will be frustrated by such a simple yet irritating issue!

5 of 5 Stars
#2

MG Chemicals 8341

We'll start by taking a look at this popular - yet also quite polarizing - flux paste. This product is without question a good all-rounder, being suitable for both leaded and lead-free purposes.

RoHS compliant and matching J-STD-004B requirements, you can at least be pretty certain not to be picking up a dud. While it performs pretty much as advertised there's a couple of things to be aware of.

First of all, this flux paste dries fast - sometimes too fast which means it is advisable to take it through a practice run before taking on a serious project. While this may take a little getting used to for those who are more used to gel-based flux, the final result is very impressive when care is taken.

The most significant issue is the pneumatic dispenser. Even halfway through the tube, you still need to allow for a 'suck back' when applying to control the speed it is dispensed at. Again - when you get used to it, that's fine but some will be frustrated by such a simple yet irritating issue!

5 of 5 Stars
#3

MG Chemicals 8341

This is a flux that is going to be a real crowd pleaser. Thanks to being slightly tacky - and of course viscous - the beauty of this product is that it doesn't dry as soon as your iron gets close but also doesn't run everywhere.

Used carefully - which the quality syringe application certainly does help with - and you will be as close as it gets to a guaranteed great finish. Residuals are easy to brush away and there is absolutely no reason why you shouldn't end up with a smart, strong and tidy job.

Plenty of people consider this to be a real star performer and it is rare for a flux to be so widely appreciated. On the flipside, there are more economical choices out there but you can be assured here of genuine quality.

5 of 5 Stars
#4

MG Chemicals Liquid Rosin Flux

Here we have a perfect example of a super thin flux liquid - something which automatically may not be to everyone's taste - but please hear us out! Despite being thin, it is also rosin-based meaning that it is very sticky (and carries quite an odor).

You will want to keep this for inside only purposes as despite being thin it will harden pretty quickly if exposed to fresh air. This is because it is also used to increase friction as a secondary purpose.

Where this product really stands out from the crowd is when used with slightly worn or older materials. It has a natural cleaning property that can transform such connections, and remember that a little does stretch a long way. Overall it serves as an excellent flux for all kinds of indoor soldering.

5 of 5 Stars
#5

SRA Soldering Products PEN_RMA SRA

Here we have a real all-rounder. You can be assured that this flux can be used for all kinds of purposes, ranging from high tech computing/telecoms through to automotive and outdoor works.

Interestingly enough, it also happens to be the first ever environmentally friendly soldering flux thanks to being totally chloride free. Even after use, it leaves behind no unpleasant residue, making this a very dependable use for those who like to think green.

The pen style may be a little imprecise for some very intricate tasks, but taken overall it does serve as a quality flux that will serve well for 99% of jobs. Quite a few electricians have adopted this as their favorite flux for all kinds of jobs, as it is an easy clean product that is renowned for its reliability.

5 of 5 Stars

best flux for soldering is good for these factors

Weight: Soldering flux is something which gets utilized again and again because of which you will need a great deal of it. Subsequently, make sure to investigate the volume or the heaviness of soldering flux that you are getting. For the most part, soldering flux arrives in a pack of two oz with a couple of makers in any event, granting four oz or sixteen oz packs for protracted time-frame use.

Consistence: Generally, you can utilize any soldering flux for your electronics activities as they all give tantamount employments. However, in the event that you favor to be ensured that your soldering flux is inspected appropriately, at that point making some thing like a RoHS agreeable soldering flux can be a top notch thought. 

Guarantee: As soldering flux is pretty much a blend of synthetic substances, they for the most part have a timeframe of realistic usability of various layers. In spite of the fact that, since you would need your soldering flux to keep going for as far as might be feasible, checking the guarantee offered by it bodes well. Fortunately, a ton of the soldering flux accessible out there offers a 1-year guarantee.

In view of these components, settling on the appropriate best flux for soldering should be really simple. Yet, in the event that you like to be absolutely certain that you are looking for the uncommon one, at that point you should also investigate their specs and significant focuses close by with a novel looking for information that you will find refered to down underneath. Utilizing these subtleties, you will be competent to buy the fine soldering flux for electronics subsequent to achieving the surrender of this article.

Who & Where Uses The Soldering Flux?

Flux is a crucial part of soldering and serves three key functions. It:

  • Removes oxidized metals from surfaces.
  • Seals out air to reduce/prevent further oxidizing.
  • Provides wetting for the soldering purpose.

They are scored using a relatively recent system - the J-STD-004 - which rates each product according to type (rosin, resin, organic, inorganic) cross-referenced by reliability and electro-conductivity. What this serves to do is make it easier for people to select a best soldering flux for eletronics appropriate to their specific needs. Professional electricians and engineers will likely carry a variety depending on the work being undertaken.

All this being said, the golden rule is that for a soldering job to be carried out well it must involve the use of flux. Sure, it can take a while to get it right - at least until you are used to a particular product at least - but it will play a huge part in ensuring the final job is as good as it can be.

How To Use Soldering Flux

Soldering various metals together is the best way of keeping them secure for an extended period, and soldering flux offers that by making the bond stronger. Despite being safe when not melted, soldering flux is very corrosive when hot. By knowing the type of soldering flux you would like to use, you can learn how to make soldering last for a long time. Therefore, in this article, we shall discuss how to use soldering flux.

#1. Having The Right Equipment

When it comes to having the right equipment there are various factors you will need to consider including:

1.
Electrical soldering

When removing oxidation from a wire, you should consider using the rosin-based flux, which works best with electrical soldering. This flux is perfect for use with electronics since they are fragile and have thin wires which do not require a corrosive flux.

2.

Pipe soldering

For pipe soldering, you will need something more corrosive, and the acid flux works perfectly. Always pipes that are made from copper will require acid flux or tinning flux since it helps in oxidizing a larger area.

3.

Electronic

Working with delicate electrical wires can be challenging; that’s why leaded solder is the best flux for working with electronics. Leaded solder often melts at low temperature, which makes it perfect for delicate electrical wires.

4.

Soldering pipes together

If you have a big soldering project which involves pipes, using silvered solder is the best due to its high melting point. When working with pipes that transport water do not use lead-based solder since it will lead to lead poisoning. However, working with lead-based solders is relatively easy, but it is not durable when compared to silvered based solder.

#2. Soldering Wires Using Soldering Flux

Here is how to use soldering flux in soldering wires:

1.

Twisting together the exposed ends of a cable. You should overlap both ends and make a small cross symbol; then, you twist them together over and around each other. Afterward, continue wrapping the wires together till both ends are pushed down into the other wire. When doing this, you should make sure that there are no pointed ends; instead, you should have an intertwining pattern along the wire.

2.

Coating wires using soldering flux. Use your finger or a small paintbrush in scooping a small amount of the soldering flux. Afterward, the area on the wire where you will be soldering should be spread with the flux. Furthermore, you should ensure that the cables are fully covered. Before soldering, wipe out the excess flux.

3.

Melting the flux. Once the flux is evenly distributed on the cable, use the soldering cable on one side to melt the flux on the wire. You should ensure the soldering iron is hot before pressing it against the cord. When using the soldering gun, the wax will melt quickly into liquid and the cable. Continue holding the iron until the flux melts entirely before it starts producing bubbles.

4.

Using solders to hold the wire together. As the iron is still pressing against the cord whole hot, press the solder’s tip on the opposite side of the cable. If the wiring is very hot, the solder will melt immediately as you continue pressing the wire. Before removing the iron, you should ensure that all the cables are well coated.

5.

Let it cool. Once the cable is well coated, you should let the solder cool and harden. Taking the iron away from the welding will start the cooling process. The solder will solidify with a few seconds, and once it has set, there should be no wires exposed. Furthermore, the two wires should be firmly connected.

Common Soldering Flux Problems

There are two issues here, though.

One issue is that flux soldering is inherently dangerous:

One issue is that flux soldering is inherently dangerous and requires good maintenance by the seasoned DIYer. Not to mention that some flux soldering is not ideal, for different reasons.

An example: I am a purist when it comes to flux soldering. The only flux I use is mercury-free. All the other types are a bad idea. Why? Mercury is a known carcinogen and the other types will not stop your solder from becoming oxidized and smelling bad when it is mixed. And then you’ll have a problem to cover, should you want to clean the solder from the system, so I’ll stick to mercury-free solder all the way.

In addition, flux is too coarse for some materials. For certain metals, the fineness will make it hard for the flux to bind properly.

Conversely, you might not need to use a flux at all.

You might have a very soft metal that bonds very easily with flux. There are also some very small solder flux mixtures that are just pure salt. This is very effective and is my preferred flux for aluminium alloys. For copper, mercury is required, but it has to be very pure, since the other materials react.

Anyway, you have to pick your poison, or get more accurate measures. If you’re using something else to solder, it is almost a moot point. But for flux, it is.

The other issue is the flux soldering machine:

You know those older tools with two cones on either end of the workpiece that spin in opposite directions? If your solder is too hot, it will flow in the opposite direction, which you can get quite easily with a fast handwind flux. So you end up with very sticky flux and heat-affected surface (HAAS) solder. And a very fine flux.

Instead, use the flux built into the solder paste soldering machine. This is an inexpensive flux iron and will be the best thing you can do. It works the best because it comes in a bigger bottle with an airtight cap, so you don’t have to measure the flux with your tongue.

Is it Okay to Solder Without Flux

In soldering, flux is used to remove metal from the surface. However, sometimes fluxing can cause it. When you can't remove the metal, you have to heat it up to heat it to a melting point. At that point, the metal will lift off with heat that you added to the solder. You will have to then heat that metal off the surface in the soldering iron, but since it is now lighter than the metal in the solder, it won't stick back to the surface. You have to go around and fill it in all over the metal, and once you do, the metal sticks properly. There are countless ways to do this, and there are a lot of different solder joint sets that you can buy. The thing is, some work better for larger joints. Some work better for cleaning, some work better when you need to build a little air gap between the thermocouple and the temperature sensor, and so on. Personally, I have always been more worried about getting the joints right. I know it's probably useless for me to say, but when you are building something like this, it's always a crap shoot as to what it is going to work with, and what you will end up needing to repair or replace after that. Personally, I've never used an electromagnet.

Final thoughts

You really can't look past the AMTECH NC-559-V2-TF Solder Flux for scoring top marks on all categories. It is an all-rounder who can match the best of the rest at their own special characteristics. It is ideal for those totally new to soldering and will still be the top pick for people who have been using their iron for fifty years.

Notable mentions ought to go to a couple of others. Silver goes to the Delcast Rosin Soldering Flux Paste which is just as good for simple electric/circuitry work despite a couple of drawbacks. As for bronze, the MG Chemicals 8341 No Clean Flux Paste will serve experienced users who can keep up with the fast drying speed very well.

Willie Ryan
 

Wille Ryan is a tool expert from the U.S. He is a Mechanical Engineer and uses tools almost every day at home and at work. He enjoys helping people to master everything about a wide range of tools through blogging. He is for sure a Tools Guardian!

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