Probably unwanted advice from running electronics benches with users of various skill:
Soldering irons are always going to waive out of calibration, especially ceramic ones, sometimes they go over temperature, other times under.
Over temperature is almost worse than under, because you wear out the tips much faster and damage your boards more often, but nobody really notices, where under temperature you just can’t solder properly/at all.
For them to get to the point they’re not working at all for @tomnewsom others must have been struggling for ages.
Any temprature sensor thats reasonably accurate can be used to calibrate once a month and keep them in check, but you might also consider changing irons, or at least having a more modern iron for rework and desoldering.
I can imagine a thermal camera might have trouble with shiny surfaces, and higher tempratures, something like this is relatively cheap.
You might also want to invest in some better more modern irons, when I left all the irons were heated core type which is cheap but old and less durable…
Heated Core
This is the oldest and cheapest technology, typical in pretty much every soldering iron you’ve ever used.
It has a heated core like a 3D printer and temperature sensor near each other, with a metal disposable tip that goes around (Hakko/Weller) or sometimes into the ceramic core.
Pros: Tips are cheap, they’re often interchangeable as the Hakko standard has been ripped off by many companies now.
Cons: They need regular calibrating, fake and poor-quality tips are everywhere, and they have a large thermal lag.
Example: Hakko FX-888D >£180
Cartridge
This is a more modern option where the entire disposable tip is one sealed component allowing the ceramic core and temperature sensor to be as close to the surface as possible.
Pros: They have substantially less thermal lag, and you can interchange tips while they’re still hot.
Cons: They are more expensive, and cheap clones are rare.
Example: Hakko FX-951 >£360
Induction
These are probably the best things you could buy, but they are often unnecessary. They use the curie point in metal combined with RF energy to regulate the temperature, so they don’t need to have a sensor in the tip measuring.
Pros: They don’t have thermal lag except for the largest soldering tasks like heat sinks.
Cons: They’re expensive, and you need different tips for different shapes and temperatures.
Example: Hakko FX-100 >£750
I’m referencing Hakko because it’s what the Maker community often uses and I am most familiar with from work. Weller, OKI/Metcal and others are great, theres also a lot of no-brand products which are great too.
The best value often comes from buying a no-brand clone which can take official Hakko, Weller or OKI/Metcal tips, I am most familiar with Zhongdi which is where are the cheap RS, Maplin, Radioshack irons normally come from, most of them use the T18 Hakko tips perfectly, and calibrated once a month are great.
Also cannot recommend highly enough 2 extra things for your bench:
- Make sure the station has a sensor in the stand to detect when it’s not being used and lower the temprature, this massively increases the life of the tips.
- Put a run down timer on your soldering stations so they can’t be left on for more than 10-20 minutes without someone pressing a button to reup the timer.
End of unrequested advice
I think this might have been my mistake.
Tom