Soldering gel. Fluxes from China: a comparative review. Types of soldering fluxes

All good! This rating contains the best soldering fluxes and is compiled from personal preference and feedback from electronics repairmen. Many readers will now think - “Well, finally! Solder Master has begun to write at least something about the soldering business! " and they will be right - for almost 4 years, not a single decent article about the soldering process has been written on the blog, although the name of the blog seems to oblige. I admit, I confess, I will correct the situation.

I plan to publish reviews of soldering processes, soldering tools, soldering videos and new technologies in the world of soldering. And today I will give my rating of the 10 best fluxes for soldering. This rating was compiled based on personal preferences and all kinds of reviews from familiar electronics repairmen of various levels and does not claim to be exclusive. Let's go - soldering fluxes.

Rating of the most popular soldering fluxes

What should we know about flux?

The flux is designed to improve the quality of the soldering process with solder of two metal surfaces and, when heated, cleans the surfaces from oxide and greasy films. Good flux should have a low melting point and low specific gravity. Before the moment the solder melts, it must have time to dissolve the oxides and not penetrate deep into the soldered joint during the soldering process. The flux should flow well and wet the surface of the solder and metal at the soldering point.

In fifth place is the most popular flux of all times and peoples, the muse of musicians, gift of nature, her majesty rosin. Rosin is gum (from the resin of coniferous trees, has almost no fatty acids), extraction (extraction of coniferous sawdust with gasoline, contains more fatty acids than gum) and tallow (residues after sulfate-cellulose soap production).

In fourth place, many beloved alcohol-rosin flux SKF or FKSp (soldering alcohol-rosin flux). It consists of 60-80% alcohol and 20-40% rosin. You can make this mixture at home with your own hands. For example, many people simply crumble rosin into alcohol in a ratio of about 1 to 3. It is convenient to use in a syringe with a needle. But when stored in a loosely closed syringe, it begins to dry out on a needle and stops flowing.

Advantages:

available and popular inactive flux, easy to apply, does not smoke much.

Disadvantages:

when heated, alcohol begins to vigorously evaporate and fizzle.

What to solder: copper wires, gold-plated and silver-plated contacts of microcircuits and radioelements, brass, zinc.

How to wash off: alcohol, solvents, gasoline, alcohol-gasoline mixture.

So we got to the Top 3 best soldering fluxes. I placed professional fluxes on the prize places, which in everyday life may not be useful. But in the craft - they are very necessary.

Amtech RMA-223 and Kingbo RMA-218 fluxes

The third bronze place is occupied by Amtech RMA-223 - it is a gel flux - a mixture of crushed rosin and solvent.

Also in the composition I suspect there may be activators and perfume. - the most important sign of a fake- on the sticker there is an inscription in small print "Coliformia" instead of "California", but oddly enough, the Chinese counterfeit flux is very good in operation, and many services only sit on it. Although the masters with mysku do not advise you to take this flux on Ali, but it is better to take an analogue.

Advantages:

it is convenient to apply the gel, good solderability, you do not need to wash it, the fake is cheap (about 200 rubles), but it is soldered with it very well and smells like perfume.

Expensive (a 10 g tube can cost 1,500 rubles), smelly, there are fakes. The price is a limiting factor, for example, a 30 g tube can cost from 2,000 rubles.

What to solder: mainly responsible lead-free and lead-free soldering.

How to wash off: most can not be washed off, alcohol, solvent, there is a proprietary solvent T2005M.

This completes the Top 10 of the best soldering fluxes. Of course, there are a bunch of other fluxes, including good Chinese and top German and Japanese ones. But I did not use them, so I cannot adequately tell about them.

If you, dear readers, use any other flux and consider it the best in the world, then be sure to write me about it in the comments. Perhaps it will appear in the rankings after testing.

The Solder Master tried for you.

Specifications

TT flux gel is suitable for soldering almost all metals and alloys.
Active in the temperature range: 110 - 250 ° С
Does not have its own electrical resistance
Residual flux protects the soldered seam from corrosion
Toxicity:
General toxicity: Medium.
MPC: 2.5 mg / m³
Allergen: Hypoallergenic.
Compatibility with materials in contact with food and skin: No data available.
General toxicity after heat treatment at 160 ° C: Low

Mode of application:
Apply TT flux gel to the area to be soldered.
Solder with solder (POS 10-90, Rose, Wood)
For SMD:
Apply TT flux gel to the area intended for planting components, with a layer of 0.5-0.9 mm.
Place components.
Treat with a hot air gun at 170-250 ° С
If necessary, flux residues are removed with alcohol or white spirit.

Commodity form:
Jars of 20 and 500 ml.
OKP code: 17 1800, not subject to mandatory certification.

Passport:
Flux-gel TT
TU 1718-001-30663583-2011
No. Name of indicators
1. Appearance Paste, dark to light red in color.
2. Content of mechanical impurities - No
3. Reaction of the medium (pH of the aqueous extract) - 2-4
4. Mass fraction of nitrogen,% - 0.15-0.25
5. Specific volume resistance, after heat treatment at 210 ° С, 10 min. With a layer of 0.5 mm., Ohm * cm - Absent.

Note:
1. Thickener - petroleum jelly.
2. MPC in air 2.5mg / m ^ 2
The guaranteed shelf life is 1 year.

Progress does not stand still, and for about a dozen years, gel fluxes have entered the market. What is their trick and what are they for?

What is Gel Flux

Gel fluxes are the same rosin, but in a gel state. I don't know the technology for the production of gel fluxes, but I know for sure that these fluxes are used for delicate soldering of radio components, as well as for repair mobile phones, laptops and other small electronics. Their big plus is that they are easily washed off (you may not even wash off) with Flux-Off, acetone or gasoline "Galoshes". You can read more about cleaning chemistry in the article Chemistry for the electronics engineer.

So, now about everything in order ...

Flux Flux-Plus

Flux-Plus considered the best gel flux.

It is a pleasure to solder with it, unless, of course, it is a fake. Repairers of mobile phones, laptops and other small electronics are very fond of it, since it does not leave carbon deposits, interacts well with solder, and we also have a pleasant smell, though not healthy for health. The only negative is its price. At the time of this writing, its cost ranges from 1000 rubles. Therefore, for a beginner there, the flux will hit the pocket very hard.

Gumboil RMA-223

RMA-223- cheap Chinese analogue the famous flux Flux-Plus. RMA (R osin M ild A ctivated) - "slightly activated rosin". A group of resinous fluxes with various combinations of activators: organic acids and their compounds.

Also there is RMA-223 and American origin. The price of the American one is slightly lower than the Flux-Plus, but also not cheap, somewhere around 500 rubles.

Chinese flux RMA-223 costs several times cheaper than Flux-Plus, but performs the same functions, not inferior to the famous Flux-Plus. I found the cheapest one for 35 (!) Rubles apiece, if you buy it in bulk on Aliexpress. In principle, I am satisfied with the quality. In order not to miscalculate with the choice of flux, there is one rule, the more yellow it is, the better the quality.

To make it more convenient to dose, I filled it in a syringe.

Since the RMA223 gumboil is viscous, a simple thin needle will not work here. Therefore, needles must be purchased separately. Choose a diameter slightly larger than a standard needle. Needle length - according to your preference.

Choose to your taste and color!

Gel fluxes and health

Gel fluxes, especially China's RMA-223, are highly toxic and highly fuming. Poorly suited for soldering BGA chips. It is good for soldering various small things, BUT think ... How much is your health worth? More precisely, how much his treatment will cost you after 5-10 years of such work. Not only does it smoke very strongly, wiping it off after soldering without residues is not an easy task!

What can be done in this case? Make a good hood and ventilate more often workplace... Try not to inhale the vapors of the gel flux. Compared to pine rosin, our pine rosin is almost harmless ;-)

What will a high quality flux give us?

1. Confidence in the quality of soldering.
2. Will not turn us into asthmatics. Reduce the chance of being bent from lung cancer, etc.
3. It will significantly save time and nerves in our hard work.

The miser pays an order of magnitude more in the end ...

Output

One syringe of RMA flux is enough for me for about a year with moderate use. When soldering, such a flux spreads very well and wets the solder. Soldering turns out like a factory one ;-), you can't tell the difference. As I said, it is indispensable for soldering and even microcircuits in phones, laptops and other small things, but it can also be used with great success when soldering your electronic trinkets. Try it and you will be surprised at the cleanliness and accuracy of the soldering ;-)

It is commonly known that fluxes are used to remove solder residues and contaminants, and to protect against oxidation.

A variety of chemical compounds are used as fluxes: rosin, phosphoric acid, soldering acid and active soldering fat, "Bura", glycerin TAGS flux, etc. Today we will talk about another type of flux - gel fluxes.

Gel fluxes are the same rosin, only in gel form. They are used for the primary and re-soldering of critical components at the household level when repairing laptops or smartphones. Their important advantage is that they are easy to rinse off or require no rinsing at all.
On the forums, you can often read that the best flux gel is FluxPlus, but there is also its Chinese analogue RMA-223. This is a big mistake! There is, of course, a Chinese analogue, only RMA-223 is a high-quality American-made Amtech flux.
What to do with Chinese counterfeits? After all, the market is large, there is demand, and there is also counterfeit. Of course, you can deal with the numbers that should be indicated on the markings, lot numbers, etc. for a long time. Or you can just buy fluxes from trusted suppliers. For example, our Amtech fluxes are purchased only from the official Amtech representative in Russia.
Today, the most popular Amtech flux grades are two: RMA-223 and LF-4300.

LF-4300 is a water-washable, medium viscosity flux that does not require cleaning and can be used with both lead and lead-free alloys. It is convenient for installing solder balls, BGA pins and reballing. This flux gel is widely used for mounting all types of Flip Chip and CSP.
The flux is water-washable, but in most cases its residues can be left on the boards. If the boards will undergo washing, then it can be removed using deionized water at a temperature of 40-60 degrees.
RMA-223 is a rosin flux and is recommended for lead-free soldering only. It has excellent applicability and wettability. Just like the LF-4300, it is used to work with components in BGA / PGA packages. The flux has a weak activity, so its residues must be washed off.

Both flux gels are marked with the letters -TF at the end. This stands for Tacky Paste Fluxes, i.e. sticky, viscous fluxes. They are often compared to honey because they must have the viscous consistency of honey and the same yellow-amber color. It is their stickiness and ductility that makes it convenient to work with solder balls during BGA soldering.

Amtech gel fluxes are supplied in a syringe, which allows you to accurately dose the flux and apply it only to the areas where it is needed, without contaminating adjacent surfaces.

When soldering, it is important to ensure an even distribution of the flux between the parts. Solid powders do not always completely cover all crevices. Liquid solutions may run.

When working with radio components, it is important that all soldering procedures are performed with great precision. Gel flux meets the requirements as much as possible. It has high penetrating power with moderate fluidity; well fills micro cavities without spreading beyond the soldering point.

The aggregate state of a flux in the form of a gel is an intermediate variant between a crystalline form and a liquid. Such a soldering composition is intended for repairing, first of all, mobile phones, laptops, computer equipment, smartphones, and others. modern means communications.

The gelatinous mass is placed in a syringe, then squeezed out in portions. You can buy special dispensers. They are available in specialized online stores.

The flux is well distributed in the work area, wets all the solder, providing a strong connection.

True, there are significant troubles with soldering. The flux gel made by our eastern neighbors smokes a lot, giving off harmful gases. Soldering has to be done in a well-ventilated place.

If you have to work a lot, then it is better to buy an expensive flux gel, not to skimp on your own safety.

Famous brands

Available in gel form. They are produced both in Russia and in foreign countries. Good reputation has a flux gel Flux-Plus.

Known products Martin, ERSA. It is easy to work with it even for novice amateurs. The cost, however, is considerable. This holds back many consumers. Costs are appropriate given constant professional work... They will pay off quickly.

Practitioners recommend the Chinese soldering flux RMA-223. Its qualities also fully meet the requirements of specialists and amateurs. The English abbreviation means activating acids are added to the rosin resins.

Experts say that the more pronounced the yellow color of the flux gel, the better it manifests itself when soldering.

The drug TT is known on the market for soldering products. It has indicator properties; upon activation, it changes color from red to colorless. The composition satisfies the solders in everything, only it is difficult to wash off.

Tips for cleaning your work area are varied. Recommended solvent lists include isopropyl alcohol, hot water, and white spirit. Ultimately, it will be possible to wash off the plaque, but this takes more time and effort than soldering.

How to do it yourself

At home, you can prepare a flux gel yourself by dissolving a large amount. If you add other substances to the gel little by little, the mixture stabilizes, and its operational properties improve.

One of the popular methods of making a flux in the form of a gel is based on mixing petroleum jelly, rosin and LTI-120 soldering solution.

It is advisable to take light pine rosin, petroleum jelly is the most common. LTI flux solution has been known and widely used for a long time. It consists of 70% ethyl alcohol, 24% rosin, 4% diethylammonium chloride and 2% triethanolamine.

At home, to obtain a gel, you can mix 30 g of petroleum jelly, 5 g of rosin and about 3 ml of LTI liquid. The sequence of actions is as follows:

The more liquid there is, the less viscosity the gel will have. Homemade flux can have a different consistency: from gel to ointment. Each master can do as required in a particular case.

The main obstacle is the price. Craftsmen do not need much trouble to make a completely suitable alternative on their own.