YIHUA 947-III soldering iron thoughts?

[kalel]

It is priced around $17, and seems to be an upgraded/better version of this thing on the right:


I have one of those (on the right), as it was around $6 with 5 tips of different shapes to choose from. So there's a high price difference.

Anyway, they claim there is some type of temperature control (assuming that the other one only has power control, which is still better than nothing):

I'm not sure what it is exactly and how it works "real-time monitoring of temperature", they point to a variable resistor, and that doesn't tell me much.

It can effectively ensure the accuracy of the temperature and to prevent temperature out of control to avoid burning soldering iron handle and other adverse consequences.

The heater element image shows two wires:

I'm not an expert by any means but I assume those two wires are just for power. Still, it might be possible to measure the resistance of the element which will change with temperature and establish some type of control that way?

I'm curious in finding out what is really upgraded/better than the "other brand", and your thoughts on how the temperature control might function.

[KL27x]

The temperature measurement happens on the other end of the cord, at the station.

From the description, it would be a good guess that when the temp of the pcb in the handle rises, it increases the voltage drop across the thermistor sensor. So it gives the station an erroneously high temp reading, causing it to reduce power to the heater. So in other words, if you set the temp to 450C, the tip will actually reach 450C as long as the handle starts out cold. But when the handle increases in temp, the output of the thermistor sensor will be increased by this circuit, and the temp of the tip will start to drop lower than it's technically supposed to be in order to prevent damage to the plastic handpiece.

The main difference between a genuine Hakko and a knockoff are two things. The heater. And the quality of the plastic. There is a lot of experience and perhaps cost in the material that goes into the handle. It is apparently cheaper or easier to just make the iron not work as its supposed to rather than achieve the same material properties of plastic that Hakko achieved 30 years ago.

I bought a knockoff recently, for business. The latest and greatest clone. For the purpose of putting a specific tip into a production line for a specific procedure. First thing I noticed about it vs my Hakko 888s is that the handle gets much hotter, much more quickly. That boils down to the two things. Heater design and the plastics. The Hakko gets more heat into the tip. The knockoff spends more energy heating the handle. How much of this is the heater design, and how much due to the plastics having lower thermal conductivity, I dunno. But there is an obvious difference.

Any 8th grader can build a soldering station that works as well as a Hakko for like 20.00 in parts. What most of us can't do is build the handpiece.

[sn4k3]

17$ for a product like that, something must be wrong, renember we always get for what we pay for. Even the 8$ fells like someone is working for free, i wonder how is possible to do such kind of product, full comercial for such value and still have good profit with it (PCB+components+handle+tips+metals+coords+whatever) is insane. If you buy a good quality AC cable maybe you will pay 8$ for it.
They even include a tip cap on the "improved version", i suspect no one will use that after start up iron for the first time, maybe just for transporting inside a toolbox...

As KL27x said the originals invest alot on material quality and design a tool that will last years with good heat optimization.
The clones are good if you want to start, hobby or use it from time a time, so spend a lot on a tool that you rarely use a clone is a win, but if you do professional work and use all day all months it will not last much time, and here is where the original stuff matters. Not only in long lasting but also in performance, you will able to do better joints at lower temperature, tips and the whole equipment will last much but much longer.

Any 8th grader can build a soldering station that works as well as a Hakko for like 20.00 in parts. What most of us can't do is build the handpiece.

Maybe with a 3D printer using Reinforced Nylon we can print a good quality handle still not that good compared with original, maybe we can print in ceramic?

[kalel]

Yes, the price is relatively cheap, but not as much comparing to competing products. There are stations for ~$20 that provide temperature control and even a temperature display. If something goes bad over time (e.g. heater, tip, plastic, etc), you can cheaply replace the complete handle.

Now, of course, you are comparing this to branded high quality products, not price competing ones. There it's definitely easy to guess (without having tried them) that for the money, you will get better materials and better reliability if soldering frequently. If soldering infrequently, it seems that these cheap solutions work too (I haven't tried the Yihua iron, I was just curious about how it works). Even the tips don't fail quickly on cheap irons (at really low volume hobby work) as long as they are tinned after each use, if not using the iron for more than a few minutes, the soldering iron is unplugged (then tinned).

[sn4k3]

Yes, the price is relatively cheap, but not as much comparing to competing products. There are stations for ~$20 that provide temperature control and even a temperature display. If something goes bad over time (e.g. heater, tip, plastic, etc), you can cheaply replace the complete handle.

Now, of course, you are comparing this to branded high quality products, not price competing ones. There it's definitely easy to guess (without having tried them) that for the money, you will get better materials and better reliability if soldering frequently. If soldering infrequently, it seems that these cheap solutions work too (I haven't tried the Yihua iron, I was just curious about how it works). Even the tips don't fail quickly on cheap irons (at really low volume hobby work) as long as they are tinned after each use, if not using the iron for more than a few minutes, the soldering iron is unplugged (then tinned).

I agree with that, if is for normal use them is a good choose opt for clones, and cheap to replace when broken.
I can say the best way to know if is good or not is by adquire and test yourself under your needs, we are talking about 17$ product so it will not break your bank and by anyway if is just garbage you put it on the bin and still you not regret because your loss is minimal. Everyday we burn money on useless things, give a chance to usefull things

YIHUA itself have more bad products than good ones but i like to give a chance to everything. Aliexpress reviews on that iron are very positive.
Also you can look at T12 Clones, they are proven to be good.
BAKON 950D another t12 clone
If your objective is portability then look at TS100, the best you can get for cheap, serious this iron is very good and put some high end stations behind, however price is a bit higher...

If you like the YIHUA iron give him a chance to shine 
EDIT: Also don't forget to test the shown temperature with the real, using a cheap meter or probe, never trust default calibration. Test for 300ºc, 350ºc, and 400ºc. If the iron deliver correct temperatures then is already a positive factor. After test for termal recovery capacity. If pass both tests is good to go.
If temperature is not real but you find a stable/fixed offset across your temperature range, then should not be a problem either. Just memorize that offset and set your temperature based on that.

[boffin]

I just gave a couple of these away in an electronics course I teach at work. 
https://www.aliexpress.com/item/YIHUA-947-II-adjustable-soldering-iron-with-5-colors-optional-portable-screwdriver-solder-wire-tips-mini/32784893247.html
At US$12.35 for a pretty decent starter kit it really is a steal, although the stand that came with it (not as pictured) is a piece of crap, bench yourself a piece of sheet metal and make a better one.

To be honest, I'm shocked how decent it was for the price.  the cord is a bit thick and unwieldy compared to a station with a separate transformer like my day to day weller, but I really think this is not just a bit of a bargain, but a downright bobby dazzler.