So how is a knife soldering tip supposed to look like?
For my first few projects I used a very cheap Toolcraft soldering iron. Now I wanted to upgrade (and also free some space in my apartment) and bought an Alientek T90B. As I am currently only solder THT parts I looked online which of the tip options on AliExpress would be the best fit for this and it said KU tip.
When I first heated up and tinned this knife tip the solder only stuck to the front edge of it and the side faces turned dark black immediately like you can see in image 1.
I then asked Gemini (I know that probably wasn't the smartest move...) if this is what it should look like and it said "No not at all! The sides should also be tinned." And advised me to buy tip tinner.
I did and used it on the tip and now it looks like the second image. So not that black anymore but with a strange dot on it that won't take any solder. I then uploaded that image to Gemini and now it said the side faces should be black and only the front edge of the knife should hold solder.
Obviously now I'm super confused. Also I couldn't find any good images of how it should really look like. So I would really appreciate if someone could tell me which of the two versions (or a different third one 😃) is the correct look for these knife type tips.
