Pigong 8858 hot air rework station and a set of assorted accessories

I've had this hot air gun sitting at home for a very long time. A friend lent it to me specifically for a review, but with all the repairs going on, I just couldn't find the time. Finally, I got around to taking a look at it to see what it's like, how it works, and of course to draw some conclusions, both positive and negative.


The seller offers lots of different bundles. This review covers the kit with extra accessories. I didn't check how much it cost, so I've listed the price for the basic version, which seems like the best option to me.

My friend also gave me a small jar of flux to try. Everything except the flux was in the same order.


I'll start with the extras so I don't have to keep coming back to them later.


Various “prying tools” and tweezers. They'd be useful to have around, if not for...


Five double-ended multipurpose tools, though I call them “prying tools”: for getting under things, prying them off, poking holes, and so on.


1. There were actually six of them; the sixth was a metal brush. All the tools are about 16 cm long, with the brush a little longer.
2. It's a useful thing, really, though I almost never use one like this. Probably because I don't have one :)
3, 4. A double-ended screwdriver, useful mainly as an auxiliary tool.
5, 6. A sort of curved awl. It's a bit blunt for an awl, but it can sometimes help pry something out of an awkward spot.


1, 2. An awl, one square-pointed and one regular, though neither could really be called sharp.
3, 4. These are probably for working with wires, for example when taking apart a transformer, or for removing something with thick leads.
5, 6. A hook and another thing—I don't even know what to call it—but it seems useful too.

The quality isn't great, of course, but it's more than good enough for occasional use.


Four tweezers of different types.


As far as I can tell, there are at least six versions in total. The ones shown below are TS12–TS15.
They're magnetic, but not magnetized themselves. Even at a glance, you can see that the quality leaves a lot to be desired.


The tweezers here are arranged by type rather than by number.
Straight, pointed: TS12 and TS14
Straight, blunt: TS13
Curved, pointed: TS14.

A small but annoying drawback: even though the tweezers are from the same “collection,” they have different stiffness. I found that rather inconvenient, for example.


Checking how well the tips meet.
1, 2. TS12: suitable only for fairly large components. You can forget about things like SMD 0805, and probably even 1206.
3, 4. TS14: basically the same thing.


Trying to grab a piece of a resistor lead with the tweezers.


1, 2. TS13 turned out to be more comfortable than the previous ones, surprisingly. But because the tips are so wide, it has a fairly narrow range of uses, at least for me.
3, 4. TS15: essentially the same as the 12 and 14, but with a somewhat unevenly ground tip.


As with the previous ones, I tried to grab a piece of lead. I managed it with the fourth pair—success, on the third take :)



A brush and flux.
At first I thought the brush came with the flux, but it actually came with the hot air gun; the flux was bought separately. By the way, I liked the brush—it’s nice and soft.

The flux has the strange name PJLSW NC-559-ASM. It costs $5.88 for a 100 g jar.

I hadn't read anything about it beforehand; I just tried it for tinning wires. Overall, it worked great—the wire tinned properly—but there were a couple of caveats.
First, this flux is very sticky. Worse, it's extremely difficult to clean off. Yes, it's considered a no-clean flux, but somehow they forgot to mention that sometimes you need to wash it off your hands, too.
Second, it doesn't evaporate completely. If you use more than you need, some of it stays on the part you're soldering—in my case, on the wire. And cleaning off the excess is difficult.
Third, I later read negative reviews online about problems with sensitive electronics that had been soldered using this kind of flux (not this specific one).

In short, it works well as a flux and has no smell, but I wouldn't use it on electronic components.

Overall, it's a mixed bag, but I put a little in a jar for myself, just in case I want to compare it with something else.


And now I've finally reached the main subject of this review: the hot air gun.
As it happens, the photo shows the exact kit that costs the stated $20.25.


The power cord is a standard one, the kind normally used to power computers. The kit also included six nozzles with diameters ranging from 3.5 to 12 mm. My friend had already used the hot air gun, and it had a 6 mm nozzle fitted, so that's the one I used for the tests.


The soldering station's “brains,” in the form of a neat little box with buttons and a display.


And right away, a few things stand out.
The display has no filter at all, so it looks like something made by a junior tech club. The control buttons are also laid out in the typical Chinese style: increase on the left, decrease on the right. I don't think I'll ever get used to that; I even ended up reworking one of my electronic loads to match the layout we're used to.
And the description clearly shows it was written by someone with a poor grasp of English.

I have no complaints about the power connector, but the hot air gun connector is installed the wrong way around: the source should have the socket and the load the plug, not the other way around. That's a safety issue.


Of course, I was also interested in what was inside, so I removed the four screws and opened the case.


The control and display board.
There are a few minor differences from other versions of this station I've seen before. The main one is that it uses a different microcontroller, or at least one in a different package.


The power board, which also houses the power supply for the electronics. At a glance, it looks quite neat.



1. There's a fuse and an X capacitor. The board is also marked YG8858B. As far as I know, this station was originally called Yihua, but it's sold under a whole bunch of different names.
2. A pair of input filter capacitors, 10 µF 400 V
3. BTA16-600B triac for controlling power to the heating element.
4. 3041 optocoupler for controlling the triac.
5. TL431 and some strange traces on the board and components.
6. The fan control transistor isn't easy to make out, but the board is marked with many of the key components: TIP122



The fan and controller power supply is built around the fairly old but decent TOP223 PWM controller.


The thermocouple signal amplifier stage. The trimmers are used to calibrate the temperature and adjust the fan supply voltage.


The soldering quality is average.


But it's really nice when the wires are labeled on the board. There are also protective slots near the high-voltage pads.


The full schematic of the power board is available online. Many thanks to the person who took the time to redraw it. You can download it, along with lots of other useful information, here. The circuit is slightly different, since this is a somewhat different station, but for the most part it’s the same.


The key difference with this station is that the hot-air gun connector has a different pinout.
That’s unusual; they usually copy everything exactly, which is easier, but I checked this several times.


For comparison, here’s the connector pinout on previous versions of the station.


This hot-air gun has a turbine, so there’s no thick hose.


I’ve already reviewed a soldering station with a similar hot-air gun, and I’ll say that in some ways this design really is more convenient than a compressor-based one. The main advantage is that the power cable is thinner and more flexible than a hose, and it’s a power cable, too.

The stand isn’t just there for show; it serves an important purpose. A magnet built into the stand and a reed switch inside the handle put the hot-air gun into sleep mode. The feature is quite sensitive: you don’t have to put the gun in the holder; usually, simply setting it on the stand is enough.


The air intake holes are on one side of the handle; the other side is just a dummy.
The heating element section is short, which makes it comfortable to use. The nozzles attach like bayonet fittings: push one on and turn it.


The nozzles fit snugly, so I have no complaints there.


In this case, I decided to take the hot-air gun apart more “for the sake of it” than out of necessity, since I’d already done that in another review.
It’s awkward to disassemble. After removing the four screws, I had to pry the two halves apart with a flathead screwdriver.


1, 2. Turbine with a rubber nozzle that directs the airflow toward the heating element.
3. Reed switch
4. Wire entry for the thermocouple and heating element.


The ground wire is simply wrapped around a tab welded to the metal part, and the metal part itself is glued in place with hot glue. That’s what made it difficult to separate the two halves of the housing.


I removed the other half of the housing to get to the heating element.


You can see both the heating element itself and the thermocouple installed at the hot-air outlet.


The controls are very simple. When power is applied, there’s a long beep, but the display stays off. Pressing the power button shows the last set temperature and starts the hot-air gun.
Once it reaches the set temperature, there’s a short beep and the hot-air gun switches to normal temperature-control mode.
A short press of the button brings up the airflow setting, from 1 to 10; holding the button down turns the hot-air gun off completely.
If you put the hot-air gun on the stand, the heating element switches off, but the fan keeps running until the temperature drops to about 100 degrees. Then the fan stops and dashes appear on the display.

And here I have another major complaint: what stopped them from adding a proper shutdown using the button, too? The thing is, the right way to shut down a hot-air gun is to keep cooling the heating element with airflow after switching it off, until it reaches a safe temperature. Otherwise, the residual heat can overheat the plastic handle.


In standby, with the fan off, the station draws about 1 W. In heating mode, power is almost 800 W, but after it stabilizes it quickly drops to 200–250 W.


Next on my list was testing it and desoldering various components from an old board, but as they say, the music didn’t play for long, and neither did the party. I was desoldering components when I noticed it wasn’t heating very well. I looked at the display and saw the temperature dropping. I thought maybe there was some kind of second sleep mode, but no.

So I started checking the heating element for continuity and found it was open. I took the hot-air gun apart again and spotted a strange little metal disk stuck in the coil, with the break right next to it. By the way, when I took the hot air gun apart for the second time, a little piece of solder fell out too—the kind you get from a cold solder joint.
I managed to repair the broken connection somehow, checked it, and everything was fine.


The station reaches operating temperature in just a few seconds, and I can say it’s noticeably faster than my compressor-based one.


But the temperature setting isn’t very accurate.


The difference is greater at lower temperatures, while at higher temperatures it gets close to zero. There’s a catch, though: I measured the temperature about 10 mm from the nozzle tip. Move the sensor a little farther away, and the temperature will be closer to the set value.


The control unit heats up during use. After about 10 minutes of operation at 400 degrees, the case temperature is around 55–60 degrees.


For real-world testing, I used an old motherboard with some fairly large copper planes and good heat dissipation.


I filmed lots of examples, but to keep the review from getting too long, I picked the three most illustrative ones.

Polyfuse


Some kind of octopus-shaped component


And a transistor. The board was already a little warm, so it came off very quickly.


I got carried away and ended up desoldering a pile of components. Now I’m wondering what to do with them, since I’m used to them being on boards and only desoldering them when I need to.


A quick summary.
Yes, it has its drawbacks: the build quality isn’t great, the controls aren’t very convenient, and there’s no way to turn the hot air gun off properly without putting it back in its holder. Even so, it works, and in my opinion it works pretty well. Considering it costs just $20, what more can you ask for? Besides, these things are mostly used by electronics hobbyists, who can always modify them to suit their needs.
For example, I’d swap the adjustment buttons around and add a switch so you can turn the hot air gun off without putting it in the holder. Maybe I’d change something else too, but I haven’t figured out what yet :)