Just took delivery of mine today.
https://www.ebay.co.uk/itm/858D-220V-SMD-Soldering-Desoldering-Station-Hot-Air-Rework-Gun-Tool-3-Nozzles/301966004104?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2057872.m2749.l2649
Had a quick look inside and it seems pretty well made. I took a pic of the board
![](http://i66.tinypic.com/2lj3ui0.jpg)
Looks like the same one I have.
nc94
Same board here.
I did some front pot calibration with a K-type Thermocouple and found the overshoot was not too bad.
Also found the results were more stable after a burn-in period, i.e. ran it at 400 for a 5 minutes, then perform the pot calibration.
Overshoot was about 5 to 10 degrees when heating upwards.
Low air flow (2 on dial)100 set = avg 103 measured
200 set= avg 202 measured
300 set = avg 298 measured
400 set = avg 402 measured
Mid air flow (4.5 on dial) :100 set = avg 97 measured
200 set= avg 194 measured
300 set = avg 298 measured , pot calibration point
400 set = avg 425 measured
High airflow (7 on dial)100 set = avg 99 measured
200 set= avg 206 measured
300 set = avg 315 measured
400 set = avg 440 measured , largest error measured
Note, tests performed ramping the temp upwards, i.e. 100, 200 300 etc. The reverse (400, 300, 200 etc) produced odd unstable results, probably due to the heater handle having thermal mass and holding heat.
So not too bad, better than I was expecting.
PS, nosel was the middle one, about 8mm wide.
Tracker