What is the flux for soldering the motherboard. Gel fluxes. Flux diluted with acid
Hello.
Today's review will focus on three Chinese fluxes that I purchased on eBay. I bought them after my home stock of this soldering accessory began to run low. Since I had not ordered this type of product from China before, and in general I did not use Chinese fluxes, I decided to buy several different jars at once, fortunately, they all cost mere pennies - $ 0.99 per item.
All three lots were ordered in the same store, so as not to rush to the post office 3 times. So the order was placed and paid for, and the next day the seller gave me a track to track it. So you can see all the information about moving a parcel from China to Belarus.
So, as I said, I ordered 3 different fluxes. 
As a test, we will try to use them to tin and solder stranded copper wires. True, the wires are terribly oxidized. I was specifically looking for three pieces that were identical in cross section and similar in contamination. 
Some kind of car connector will act as an object of soldering, which has been idle in my garage for many years. He also managed to pretty much oxidize and dust. For the purity of the experiment, neither the wires nor the connector will be cleaned before the start of the “procedure”. Actually, the connector itself to which we will try to solder the wires (to a metal arc): 
But before proceeding directly to the review, let me remind you what a flux is and what it is for. Flux - substances (usually a mixture) of organic and inorganic origin, designed to remove oxides from the surface to be soldered, reduce surface tension, improve the spreading of liquid solder and / or protect against environment.
First - RMA 223, ordered .
It is delivered as if in a syringe, however, this syringe has neither a piston nor a needle :) But you should not worry about it accidentally leaking out.
Description (Google translation):
Type: RMA-223.
Good dive;
Volume: 10ml / 10cc;
Size: 95 x 35 x 23 mm.
RMA-223 is a high viscosity impure flux, it can be used to recycle PCB, BGA, PGA, it can be used to solder and reball computer and phone chips. It is a mixture of high quality alloy powder and resinous paste flow, it can avoid pale yellow residue, so you can easily clean the board.
This flux has a gel-like consistency, which makes it easy to apply. Outwardly, it has a pale yellow color, in the light it is cloudy. 
When heated, it spreads perfectly and smokes :) I would like to believe that it also actively penetrates between the strands of the wire. 
Second - PPD PD-18, (although PD-10 is written on the jar) was ordered.
Unlike the first one, it comes in a metal jar, somewhat reminiscent of jars from Asterisk balm, although several times larger. If in the first case the syringe was airtight, then the iron jar turned out to be not such a reliable package. At the time of receipt, it was all in flux, both inside and out. Carefully wiped everything, threw it into the shelf. Got it after some time - again the same story. So you need to store it carefully, do not allow the jar to turn over, otherwise its contents may not live up to soldering - it will leak out. 
Description (Google translation):
Type: PPD PD-18;
Weight: 10g;
Peculiarities:
joint high intensity;
Good dive;
Neutral PH7±3;
No poison no;
Good insulation;
Smooth welding surface;
There is no wear.
In its consistency, it is thicker than the first one and has a more pronounced Orange color. They smell similar, but it's hard to say exactly what they smell like. The smell is familiar, but I don't remember exactly what.
An open jar provides excellent access to the contents. If you want to dip the postings, if you want to shove the fee :) 
When heated, it also spreads beautifully and smokes perfectly. There seemed to be a little more smoke than in the case of the first one and it was more caustic.
Third - XY-5 (solder rosin), ordered .
Like the second option, it comes in a jar, though not metal, but plastic. 
Because of solid state can be perfectly transported and permanently stored even in your pocket. Nothing will leak out, nothing will get dirty.
In the solid state, there is a rich amber color familiar to everyone who has worked with rosin. During heating, it melts with copious emission of smoke, which has the smell of resin, which is not surprising :) To be honest, my favorite option. Heated, it spreads well, but it also cools down quite quickly. Crumbles when solid.
Description (Google translation):
Name: Solid rosin;
Weight: 22 grams (including box).
Ascetic, but what we have, we have :)
Perhaps it is not entirely correct to compare the first two samples with this one, but, according to by and large, and the first, and the second, and the third are flux and are used for the same purposes.
So, let's begin.
The first wire was soldered using #2 PPD PD-18 flux. Due to the abundance of pollution and the rather large cross section of the wire, the solder had to be used not so little: (But the result was not long in coming - the wire was soldered: 
Without the use of flux, the solder on the bracket refused to stick at all. If you look at the photo above, you will see how it flowed from her, spreading over the plastic.
The second wire was soldered using hard flux No. 3 XY-5 (or rosin). To be honest, the first attempt was not entirely successful: the wire fell off the connector bracket along with all the solder :) But you can see how all the dirt gathered on the solder, and a place appeared on the bracket without pollution: 
But on the second attempt, he still took his place where it was required.
Flux #1 RMA 223 was used last. 
Hedgehog hedgehog, but the most important thing that is required from the flux is the hardening of the joint during soldering. So the simplest thing that came to my mind to check the results is to try to tear off the soldered wires :) Result: 
As you can see, flux No. 2 worked perfectly: the solder itself remained in place, and the wire simply broke it. True, I had to pull with a fair amount of effort. Flux No. 3 (rosin) also turned out to be quite good: no matter how I pulled, the wire remained in place. The only thing that we managed to separate was the insulation from the cores :) But flux No. 1 failed. The solder just fell off and I didn’t have to strain too much for this :(
Conclusion: RMA 223 is not worth taking, it does not cope with its task as a flux (because it is more vaseline, and not a flux as such). But the XY-5 and PD-18 showed themselves with positive side. Choosing between them, I would prefer solid flux only because it is more practical to store it, and its smell is much more pleasant :) But everyone decides for himself what to buy.
Yes, to improve the results, it would be possible to tin the wires and treat the bracket with phosphoric acid, but I wanted to know which of the fluxes would perform better in the harshest conditions :)
On this, perhaps, everything. Thank you for your attention and your time.
I plan to buy +31 Add to favorites Liked the review +49 +86There was a need to change BGA chips. Accordingly, the question arose and with what flux it is better to do this. Purchased Russian did not impress me. Having soldered wires with this flux, I realized that this is a pretty good flux - a little worse than rosin. But most of it quickly boils away. I decided to do flux BGA myself. I did not achieve any special results, but it can be useful to those who do not have the opportunity to buy a flux.
Main features of BGA flux:
1) it can not be washed after soldering (inactive + does not leave dirt)
2) the ability to spread under the chip
3) working temperature - about 220°С
It turned out that there are not so many available components suitable for the manufacture of any flux. Here is their list:
rosin (inactive)
Ammonium chloride (inactive; 338°C)
hydrochloric acid
zinc chloride (dry melting point 318°C, boiling point - 732°C)
acetylsalicylic acid (140°C)
sodium carbonate (820°С)
glycerin (160-290°С)
wax (protective flux)
stearin (protective flux)
vaseline (protective flux)
oleic acid (protective flux for aluminum soldering; found in olive oil)
machine oil (protective flux for aluminum soldering)
In the process of experimentation, I developed three fluxes that can be made from available materials:
Flux #1
Glycerol. Just pure anhydrous glycerin. Very good as a flux and has a high boiling point, which will not allow it to boil away quickly.
Unfortunately, I did not find anything to loosen and thicken glycerin. Therefore, I use it in its purest form. You can get it by evaporating pharmacy glycerin. To do this, it must be kept at a temperature close to the boiling point for a day or more, until the volume is reduced by a factor of three. Should be washed after use.
Flux #2
Glycerin with aspirin. Prepared by dissolving acetylsalicylic acid in hot glycerin. Has a mushy state. Too good as a flux. You also need to rinse after use.
Note:
Aspirin is an inactive flux. And I was convinced of this by smearing a soft copper wire and kept it like that for a week. There were no signs of corrosion after that on the wire.
Flux #3
Wax with rosin. Prepared by dissolving rosin in hot wax. The wax is here as a base, allowing small amounts of rosin to spread evenly under the chip. Pretty decent flux, a little worse than rosin. It has a drawback - it leaves dirt like rosin. I think if the rosin can be cleaned (for example, by recrystallization), then such a flux can also be used for BGA. The main advantage is that it does not need to be washed off after soldering.
The flux is quite thick, but this only affects the convenience of its application.
Today on the shelves of radio markets and electronics stores you can find great amount soldering fluxes of various purposes and prices.
Flux manufacturers offer products really High Quality, but it is quite difficult to find it on the market. The number and variants of fakes are simply amazing in their diversity. Even if you are lucky and you find an original product, its cost will differ significantly from the cost of a fake. Most potential buyers after comparing prices decide to save money and look for a cheaper flux. Masters, on the other hand, select the optimal set of soldering chemistry for their requirements, arranging them according to their requirements. technical parameters and price. But for this they have to go through unknown fluxes and, through experiments, select the most suitable option for one job or another.
Almost every corner sells hundreds of cheap fluxes with high performance on the label. But inside the package you may expect a very unpleasant surprise.
And now let's figure it out how fluxes are bred and how this affects their technical characteristics.
Rosin instead of flux
Imagine the situation: you bought a superflux, open a tube, and instead of a high-quality flux, there is low-quality rosin (waste after rosin production). Moreover, the same rosin is also very diluted with some kind of contaminated technical petroleum jelly.
Soldering or tinning with such a mixture is simply impossible. The so-called "flux" begins to "run away" from the place of soldering. As a result, we get undeserved conclusions, poor-quality "cold" soldering, and contact pads and tracks instantly fall off the board due to overheating.
Flux diluted with acid
Very often, acids (citric, orthophosphoric) or chlorides (zinc chloride) are added to an already low-quality flux. Compared to rosin, the picture immediately changes - everything is tinned and soldered. It seems that the flux is just super, but soldering with such a flux electronic boards it is forbidden. It is very difficult and sometimes almost impossible to remove acid residues, especially from under SMD elements. Acid can even remain inside the solder, in the pores of the solder.
As a result, after a month or two, soldering with acid (or zinc chloride) crumbles into powder along with the conclusions of the radioelement. Repair then will be very, very laborious, and sometimes it is completely impossible.
Flux diluted with glycerine
It also happens that glycerin is generously poured into the flux. Glycerin flux solders great, it's cheap and plentiful, but try covering the board with it. And then measure the resistance of the PCB board. That's bad luck: it conducts current from a few to tens of ohms where it should not. Even if you try to wash off the glycerin, and it is washed off easily, the “conductivity” of the board will still remain! Glycerin is absorbed into the textolite (resistance of textolite not covered with copper is 10 to 50 ohm). For most devices, this is simply unacceptable. Even the most simple and banal schemes will be “buggy”. To somehow make the device work, try scratching the textolite between the tracks with a needle.
Conclusion: glycerin, acids, chlorides in non-cleaning fluxes for working with radio electronics, BGA and SMD components should not be used.
Basic requirements for a high-quality flux for working with lead elements, BGA and SMD:
- no corrosivity
- good lubricating properties
- high wetting ability
- no boiling when heated to operating temperature
- lack of electrical conductivity
- ease of removal of residues if necessary
- support for lead-free and lead-containing solders
- no-clean soldering technology (remains can not be washed off)
- ease of application (gel, paste)
- affordable price.
Now let's see what they offer us on the market.
Fluxes meet all of the above requirements trademark CHIPSOLDER FLUX.
The fluxes of the series are also of sufficient quality. SP (SP-10+, SP-15+, SP-18+, SP20+, SP30+).
They do not contain acids, chlorides or glycerin. SP fluxes are available in different consistency: paste, gel, liquid (L-NC-3200, L-NC-3600). They don't spend electricity, and it is not necessary to wash off the remains.
These fluxes comply with all declared standards and have been tested when soldering lead parts, conductors, BGA and SMD elements, as well as sensitive solar panels.
Flux characteristics and their features
Let's now look at some of them in more detail.
First, let's deal with the name. What do all those big letters stand for?
- G(gel) - gel-like flux.
- NC(no clean) - does not require rinsing.
- 5268 - flux index.
- LF(lead free) - suitable for lead-free solders.
CHIPSOLDER G-NC-5268-LF
This flux is suitable for soldering tinned contacts. It has good thermal conductivity, the contact pad remains on the board, and not on the soldering iron tip. Flux gel CHIPSOLDER G-NC-5268 LF is a high quality, translucent, synthetic no-clean flux with resinous characteristics. Used for soldering and desoldering BGA/SMD components. Suitable for working with a soldering iron, hot air gun, IR station, as well as for reballing.
The flux is made from highly purified components. Conveniently fixes BGA and SMD components when soldering ("landing"). Fully supports both conventional and lead-free soldering technology. Halogen-free for long-term reliability and excellent performance soldering.
It has a minimal, "soft" activity during soldering, which allows you to not wash off residues. It does not boil, does not leave a dark "soot", after soldering it remains a transparent gel. It loses transparency only at a temperature of -5 ° C, but at the same time retains its properties. Easily removed with any universal remedy on an alcohol (alcohol-petrol) basis and paper napkins.
It has excellent thermal conductivity (the component heats up as evenly as possible), it is very convenient to use. Solvent-free, does not dry out in the open air and does not harden after soldering. Suitable for multiple use.
CHIPSOLDER-G-NC-6500-LF
These fluxes are similar in performance to the CHIPSOLDER flux series, but are slightly less expensive. It should be noted that the cost did not affect the quality. They can also work great and get good results. And now let's dwell on each of them in more detail.
SP-10+
This is a cheap and pretty good low-active flux. It is recommended to use for mounting and dismounting FLIP CHIP, BGA and SMD components, crystals, as well as for repair work using a soldering iron, hot air gun, IR equipment.
Has almost zero activity. Used for soldering and desoldering tinned leads. Suitable for lead-free solders. SP-10+ is absolutely safe for radio components. Evenly distributes soldering temperature and prevents peeling of printed conductors. It has a sticky consistency (viscous, sticky), does not cause corrosion, securely fixes the elements during soldering. It also does not conduct electricity.
The flux is used without subsequent washing in printed circuit assemblies. Suitable for work in various conditions environment.
SP-15+
The main difference is in the consistency.
SP-30 It is a translucent, sticky gel. Flux is intended for repair and production of electronics. Can be used with all standard solders.
So, let's sum up.
All fluxes are formulated for high quality soldering. All of the above fluxes are used in various environmental conditions and under different features process.
The main differences between SP fluxes are consistency and potency. Therefore, it is necessary to select the flux based on the scope and convenience during operation.
As for CHIPSOLDER brand fluxes, they are not as versatile as SP fluxes. When choosing a CHIPSOLDER flux, you definitely need to know how to use it and for what purpose.
Natalia ZinkoProgress does not stand still, and gel fluxes have entered the market for about a dozen years. What is their feature and why are they needed at all?
What is gel flux
Gel fluxes- this is 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 repairs 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 Galosha gasoline. You can read more about cleaning chemistry in the article Chemistry for an 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 him, unless, of course, it is a fake. Repairers of mobile phones, laptops and other small electronics are very fond of it, as it does not leave carbon deposits, interacts well with solder, and also has a pleasant, though not healthy, smell. The only downside is its price. At the time of this writing, its cost ranges from 1000 rubles. Therefore, for a beginner there, the flux will hit your pocket very hard.
Flux 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.
There is also RMA-223 and American origin. The price of an American one is slightly lower than Flux-Plus, but also not cheap, somewhere around 500 rubles.
The Chinese RMA-223 flux is several times cheaper than Flux-Plus, but performs the same functions, in no way inferior to the famous Flux-Plus. I found the cheapest one for 35 (!) rubles apiece, if you buy in bulk on Aliexpress. In principle, the quality is satisfied. In order not to miscalculate with the choice of flux, there is one rule, the more yellow it is, the better it is.
To make it more convenient to dose, I poured it into a syringe.
Since RMA223 flux is viscous, a simple thin needle will not work here. Therefore, it will be necessary to purchase needles separately. Choose a diameter slightly larger than a standard needle. Needle length - according to your preferences.
choose
to your taste and color!Gel fluxes and health
Gel fluxes, especially Chinese RMA-223, are highly toxic and smoke heavily. Not suitable for soldering BGA chips. It’s good for soldering various small things, BUT think about it ... How much is your health worth? More precisely, how much will his treatment cost you after 5-10 years of such work. Not only does it smoke very strongly, it is not an easy task to wipe it off after soldering without residue!
What can be done in this case? Do good hood and ventilate more workplace. Try not to inhale gel flux fumes. Compared with pine rosin, our pine rosin is almost harmless ;-)
What will give us a high-quality flux?
1. Confidence in soldering quality.
2. Will not turn us into asthmatics. Reduces the chance of dying from lung cancer, etc.
3. Significantly save time and nerves in our hard work.
The miser ends up paying an order of magnitude more ...
Conclusion
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 is obtained as factory ;-), you can’t tell the difference. As I said, it is indispensable for soldering and even chips 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 by the cleanliness and accuracy of soldering ;-)
For good soldering of BGA chips, a high-quality flux is needed - the quality or the possibility of soldering in general depends on it.
When you first get acquainted with chip soldering or reballing, most people are in no hurry to buy real original fluxes from popular manufacturers, and consider it enough to start trying the Chinese analogue. I will say unequivocally: soldering with Chinese cheap flux and original ones are two completely different things. I was convinced of this, at the first attempt to roll balls through a stencil to a chip from a video card. I used the most popular Chinese RMA-223 flux. Its price in the aliexpress store is the most attractive. Nothing worked out for me: several balls constantly did not want to lie down on the contact pads, so I had to repeat the procedure several times. Moreover, if from the first attempt to melt the balls they did not stick to the site, then at least how much gray is useless.
This led me to look for a quick solution. To begin with, I tried to repeat the procedure with alcohol rosin. Nothing happened, because the rosin burned, and the balls simply did not have time to melt. But I noticed that those that melted immediately lay down on the ground.
The main feature of fluxes for BGA soldering is the ability long time retain their properties high temperatures and no effervescence. As for the Chinese flux, it does not darken and does not fade at high temperatures, but its flux properties leave much to be desired.
Therefore, the idea came up to modify the Chinese RMA-223 flux by adding rosin to it (in my case, alcohol rosin), but for this it is necessary to get rid of alcohol, which will lead to the flux boiling at high temperatures. This recipe helped me a lot, I use it to this day and not only for BGA soldering. Since it has a thick structure, the flux is convenient to apply when soldering. SMD elements and other details. It does not have to be washed off after soldering.
So, you will need:
1. Flux Chinese RMA-223
2. Alcohol rosin LTI-120 (can be replaced with another alcohol rosin)
3. Metal container for heating (I took an aluminum flask from under the film)
4. Spatula for mixing (in my case, a pencil)
Procedure:
1. Squeeze RMA-223 flux into the container.
2. Warm up the flux until it becomes liquid.
3. Add alcohol rosin LTI-120, in a ratio of approximately 1:3 (that is, LTI-120 - 25%, RMA-223 - 75%).
We heat the resulting slurry, stirring with a spatula until a slight boil. For heating, I used a hot air gun.
4. We continue to heat until the boiling stops or becomes very weak. This will indicate that the alcohol has evaporated from the slurry.
5. While the resulting flux is hot and liquid, we draw it into syringes.
All! The flux is ready, after cooling, it will become as thick as it was originally and acquire properties good flux. In comparison with the original fluxes, I personally did not notice the difference. It also provides high-quality soldering and is easily washed off without leaving stains or burns.
Hope you enjoy this recipe.