Solder flux Mechanic MCN-UV80

This Chinese soldering flux was recommended to me by several readers at once, as another good Chinese flux. He was intrigued and decided to take a jar for a sample.
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From the Mechanic’a, by the way, you can see on salea variety of related materials for soldering and manufacturing printed circuit boards. I also have a one-component solder mask, but this is a topic for a separate large review. As for the fluxes, I basically came across two versions on the aliexpress trays - MCN-UV80 and MCN-UV50, and as I understood, their difference in weight.

On the bank there is a colored glossy sticker withnecessary information and (of course, where without him) - a logo with a serious bearded man. The bank also has QR codes and a protective layer, apparently for checking the authenticity of the product.

There is also a sticker on the side, it is reported that the flux is suitable for soldering boards, as well as SMD / BGA

Another QR code on the bottom of the can

Inside is a neatly bathed substance of a dark yellowish color. It smells of rosin, which is not expected.

Picked up the sample on the tip of the toothpick - verytough and very thick. Perhaps the thickest flux that came across to me. If you try to take a small amount of flux with a toothpick, then thin long hairs are pulled behind it - so much so that it is sticky and sticky.

First of all, I applied a little bit of this flux to the group of copper pyataks on the breadboard and examined this place a week later - no oxides appeared in the form of greening on the copper contacts.

This is followed by a test for current conduction. For this, I had a dough plate with two separated contacts. I apply and smear the flux in the middle of these contacts.
I measure resistance tester - infinity.

Now I apply a heated soldering iron tip to one of the contacts so that the flux begins to melt

At first, resistance appears (leftpicture), but after a few seconds, it quickly goes to infinity (right picture). Last time I considered the LAOA LA813002 flux, - so he completely failed this check and the conductivity remained there even several hours after cooling, which makes it completely unsuitable for SMD soldering. the submerged flux under the element is no longer precisely washed. If you compare Mechanic with a good compromise in the form of Kingbo 218, then the restoration of infinity after warming up the flux, passes more quickly at the Mechanic flux.

Now we turn, in fact, to the fluxing and other properties of the flux.
Tinning of a fragment of a fiberglass board

Slag, apparently not left. Under the slags here is meant various debris in the form of burning, scale and other things.

Tinning stranded wiring

Soldering two stranded conductors

Soldering a twisted pair conductor to a nickle on the board

Anode batteries, tinning

Soldering the contact comb to the board

Washing off.
Hit a pair of coppers on the board using Mechanic Flux

It is worth recalling once again that the flux is very sticky, and remains so even after heating. Therefore, it is not possible to clean the flux from the board the first time.
Each pass includes wetting with a mixture of "alcohol + gasoline" Kalosha "(1: 1) and 2-3 seconds rubbing with a toothbrush.
First pass: there is still some amount of flux smeared with a brush on the surface:

Second pass: already more or less clean

Solder the SMD resistor with hot air.
The flux for soldering SMD at least should not boil, otherwise the element will not sit. In this example, the resistor is soldered normally.

After washing

Tinning closely spaced contacts
This example makes it clear whether solder snot will be pulled between adjacent contacts using this flux. As you can see, this "side effect" is not manifested here.

Finally, I soldered the Attine13 microcontroller inSMD package SOIC8. On the contact pad previously applied a small amount of Mechanic flux. The whole operation took a few seconds, except for the moment of reversal of the breadboard.

Physical Properties
The density and stickiness of the Mechanic flux turned out to bea little help for other semi-liquid fluxes, since the flux can be easily picked up with any sharp object, be it a match or a toothpick, applied to the surface in any plane and smeared over it. With semi-liquid fluxes, which are usually found in syringes with needles, this procedure is somewhat delayed.
Reaction of exposed conductors to flux. Earlier, a couple of times I had to deal with such an unpleasant situation, when after soldering with Kingbo 218 flux over time, if the flux was not washed, the copper coating on the board was covered with a green coating, that is, oxidation of the contacts occurred and as a result - their slow destruction . If we talk about Mechanic, then the copper coats on the breadboard underneath it did not oxidize over a week, so even if partially the flux remains after washing, it will be at least clear that the contacts will not break.
Washing off
As mentioned, flux due to its propertiesthick, sticky, sticky. And washing does not occur from the first pass. The mixture for cleaning the boards using the same - isopropyl alcohol + gasoline "galosh" in the ratio of 1: 1
Smell and density of smoke
The amount of smoke is the same as soldering 218th and559th, average. I did not notice much difference here. However, the smell has big differences. If the 218th and 559th are a sharp, pronounced chemical smell, then in the case of Mechanic, the smell is no longer so nasty, i.e. there is no longer a characteristic chemical “flavor” after soldering. A minor plus, but you still cannot breathe and it is strongly recommended to use the hood during soldering work.
National disaster Chinese fluxes. With a short (several seconds) heating to 260-280g., The flux begins to conduct. After cooling, the resistance tends to infinity and the substance ceases to conduct. If we talk about such a parameter as the speed of recovery of resistance to infinity, then Mechanic bursts forward. The flux Kingbo 218 infinity of resistance during cooling restores much longer, this is not surprising, since it is more active. The flux (also known as fat) from LAOA failed the test altogether and kept the resistance of a small amount even a day after cooling.
So that the activator in the flux is completely decomposed,It is necessary to withstand the thermal profile or, more simply, “fry” the flux at a temperature of at least 260 g. within 40-60 seconds. As I have already said, the flux does not conduct current in a quiet state and does not oxidize the contacts, but if you use it for soldering with a soldering iron, then a good habit of washing it from the board will not be superfluous. For BGA use it, I would be careful. For SMD it is possible, but washed off and if you know that the elements will not get very hot during the operation of the end device.
Bulk properties
I first soldered the 218th, then the mechanic, and byKingbo's speed of tinning might be a bit faster than the Mechanic, - the difference is quite small, and it was not even noticed the first time. On the quality of the tinning, I did not find any obvious differences.
SMD super-sized soldering.
Fortunately, the “mechanical” flux does not boil, and, in addition, is sticky, the SMD component, when brazing with hot air, sits in its place without any problems. However, it was shown above.
Kingbo 218 after work could leave somethe amount of slag on the working surface, in the form of black flakes. In the case of the Mechanic, the surface remains much cleaner. The melted flux thus acquires a dark yellow shade. On the very tip of the soldering iron, a small amount of slag remains, but they are always concentrated in the upper part of the tip. In the picture below, the sting is already cleared, but the arrows indicate the place of accumulation of slags for understanding.

Globally, Mechanic is not perfect.flux, but from Chinese, I consider it a preferable choice than Kingbo 218. So this is quite a “stone in the garden” of the 218th. I will use, and then we will see, thanks for the tip to the readers.
- Does not litter the place of soldering by slags
- Well-tinted surface
- Does not boil and does not stink
- Does not oxidize copper
- not washed the first time
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In the comments they asked how I soldered two wiring and they did not go away during the soldering.
1) We clean two conductors with a stripper

2) Lightly fluff them

3) Combine them like this:

4) Squeeze the “pigtail” around the circumference, then apply the flux and solder