Measuring the temperature of a soldering iron tip - Page 1
Forum section: electronics / testgear

author: smbaker
author_rank: Regular Contributor
timestamp: March 04, 2023, 06:29:31 pm
content: Recently my favorite xytronic iron failed, and I replaced it with a Hakko 888D (mistake! won't do that again!). It feels to me like the Hakko is is soldering at a much lower temperature than the xytronic did. I'd like to find a way to accurately measure the tip temperature on the Hakko so I can calibrate it. I have a fluke multimeter with a type-k thermocouple. Is holding the thermocouple to the tip of the soldering iron an appropriate technique? I'm using nothing other than hand pressure to press the thermocouple to the tip (holding it several inches back, of course).Unfortunately, the current xytronic I had been using is kaput so I don't have its data point. But comparing my Hakko to the very first iron I ever owned, a 30-35 year old xytronic, both set to 370C, I'm reading the following:Old xytronic: 350CBrand new Hakko: 280CI also have a seek thermal iphone camera, which while I don't believe is giving me accurate temperatures, but it too is showing the Hakko significantly cooler than the other iron.Scott

author: mendip_discovery
author_rank: Super Contributor
timestamp: March 04, 2023, 06:53:02 pm
content: You can use a k-type on the end, and add a bit of solder to help transfer the temp. But it is never really that accurate.I have played with the "Solder Iron Calibration Unit" things you can buy on ebay and amazon but never used one to test a proper probe.I always think it is a bit of a joke because if the solder doesn't melt, they just up the temp. It get funnier when asked to measure the temp of a hot air gun.

author: Fungus
author_rank: Super Contributor
timestamp: March 04, 2023, 07:40:55 pm
content: Quote from: smbaker on March 04, 2023, 06:29:31 pmYou might have to hang a blob of solder from the tip of the iron and put the thermocouple inside it.Another trick is to start with a cold iron and hold some 60:40 solder to the tip while it heats up.Watch the temperature while you do it. What number does it show when the solder melts?Quote from: smbaker on March 04, 2023, 06:29:31 pmTurn it up until they both show the same on the camera. That's your data point.I have one of those Hakkos and I find that trying to change the temperature is such a pain in the ass that I don't bother. I found the point at which my solder melts (using the technique above) and added 50. That's where it stays, I never have any problems.(Worst user interface ever)

author: timeandfrequency
author_rank: Frequent Contributor
timestamp: March 04, 2023, 08:32:03 pm
content: Hi smbaker,Such asolder iron temperature testershould be helpful for your purpose.Another brand

author: wraper
author_rank: Unknown
timestamp: March 04, 2023, 08:36:21 pm
content: Quote from: smbaker on March 04, 2023, 06:29:31 pmLikely you are measuring both incorrectly, it's very easy to get lower than actual reading. Also it's possible that Hakko has correct temperature but Xytronic higher than set. Also where did you buy 888D, are you sure it's genuine?QuoteNope, it must be a thin thermocouple inserted into a molten blob of solder.

author: pope
author_rank: Frequent Contributor
timestamp: March 04, 2023, 09:21:36 pm
content: Quote from: timeandfrequency on March 04, 2023, 08:32:03 pmDo these actually give provide measurements?

author: wraper
author_rank: Unknown
timestamp: March 04, 2023, 09:25:18 pm
content: Quote from: pope on March 04, 2023, 09:21:36 pmFrom what I've seen in reviews of cheap hakko calibrator knockoffs they work fine.

author: shapirus
author_rank: Super Contributor
timestamp: March 04, 2023, 09:35:00 pm
content: Quote from: pope on March 04, 2023, 09:21:36 pmI have the same (that is, looking the same) as the one that the first link points to. The value it displays matches what I measure with Brymen BM869s. Of course it's much more convenient than using a DMM, which is the whole point of getting one of these. DMM is not less accurate, as long as the thermocouple tip is tiny and can be entirely put into a blob of solder on the tip, but the dedicated device is more handy.I say it's pretty good, and I can't see how such a device, under any brand name, could ever be justified to cost more than $10-$20.

author: Fungus
author_rank: Super Contributor
timestamp: March 04, 2023, 09:53:16 pm
content: Quote from: timeandfrequency on March 04, 2023, 08:32:03 pmOh, you evil, evil person!You sent me to the French Aliexpress site so now Aliexpress will be in French forever.(Not as bad as sending me to the Russian site. People who post links to Aliexpress Russia are destined for a special corner of hell)

author: pope
author_rank: Frequent Contributor
timestamp: March 04, 2023, 09:55:06 pm
content: Quote from: shapirus on March 04, 2023, 09:35:00 pmI also use the 869s to measure the tip but it's a bit of a pain and I s thinking of getting one of these cheapo ones. I'm just not convinced that they can perform well but I might give it a go. Which one do you have?

author: timeandfrequency
author_rank: Frequent Contributor
timestamp: March 04, 2023, 10:20:41 pm
content: Hi Fungus,Quote from: Fungus on March 04, 2023, 09:53:16 pmI would say this could be a good opportunity to learn a foreign language. But I have to mention that the chinese -> french translations on Aliexpress are often outlandish.Delete the cookies stored in your navigator. This will revert to the default setting (chinese).

author: shapirus
author_rank: Super Contributor
timestamp: March 04, 2023, 10:21:04 pm
content: Quote from: Fungus on March 04, 2023, 09:53:16 pmhere you go:https://addons.mozilla.org/en-GB/firefox/addon/global-aliexpress/

author: shapirus
author_rank: Super Contributor
timestamp: March 04, 2023, 10:23:55 pm
content: Quote from: pope on March 04, 2023, 09:55:06 pmI ordered mine here:https://www.aliexpress.com/item/32882463397.htmlBeware, it uses a 9V battery. It however works fine with those rechargable ones that have a 2s lithium battery and a charging circuit inside with no dc-dc conversion on the output (just as well as my BM869s btw).

author: smbaker
author_rank: Regular Contributor
timestamp: March 04, 2023, 10:27:42 pm
content: I purchased the Hakko on Amazon from a third-party distributor who is listed as an official distributor on the Hakko website. So I'm assuming it's legit.I don't doubt that I could be measuring the temperature inconsistently with the thermocouple. I just watched a Big Clive video where he showed the same thing, having to fuss around with it a lot, getting inconsistent temperatures depending on how and where he touched the thermocouple to the tip. The measurements I reported earlier were taking the maximum of a number of attempts, but that still doesn't guarantee I received a correct result.I have ordered one of the cheap testers, ought to be here mid next week. Then I'll run some measurements on the new Hakko and the ancient Xytronic and see if I can get consistent measurements. When the pace arrives, I'll measure that too. I also found a replacement heater for the (less ancient) broken Xytronic. I'll repair it and measure that too!Ultimately though, the reason why I went down this measurement avenue is because something didn't "feel right" when using the new Hakko, and I wanted an objective measurement. There's something amiss. So I'll see if that objective measurement backs up my subjective impression.Agree on the Hakko having the worst interface of any piece of equipment on my bench. It's worse than programming a 1980's VCR. It's like some bean counter declared "you must reduce the cost of this product by one more nickel" and the engineer replied, "the only way I can shave off another nickel is to eliminate the down button", and the two-button interface was born. Who in their right mind wants to set each digit of the temperature individually?Scott

author: timeandfrequency
author_rank: Frequent Contributor
timestamp: March 04, 2023, 10:46:17 pm
content: Hi smbaker,Sure that if your soldering experience is significantely degraded with the Hakko, there might be a botched temperature calibration or PID parameters between iron and station, or a bad thermal coupling between the heating element, the temp sensor and the tip.However, the thermal inertia of the soldering tip is also very important, and some brands tent to lessen the amount of metal they use to manufacture a soldering tip.

author: Fungus
author_rank: Super Contributor
timestamp: March 04, 2023, 11:08:31 pm
content: User interface aside, mine solders perfectly.What's the wattage of your old iron compared to the Hakko? Maybe you're noticing a difference in Wattage. It will be noticeable if you're soldering big stuff and/or thick wires.

author: IanB
author_rank: Super Contributor
timestamp: March 04, 2023, 11:19:55 pm
content: I have a Hakko FX-888. Luckily I bought it before they downgraded it to the 888D. I find it solders very well, but one thing I do with all irons is to dispense with the fine conical tip that often comes as standard and replace it with a much bigger flat tip or horseshoe tip. The conical tip will not deliver enough heat unless you are soldering very tiny things.

author: smbaker
author_rank: Regular Contributor
timestamp: March 04, 2023, 11:58:41 pm
content: The old iron was 90 watts, and the new Hakko I believe is 75 watts. So yes there's a decrease in wattage, but I'm also merely soldering DIP IC sockets to a 2-layer board. 75 watts ought to do it. I like the fine conical tip.Miscalibration is a possibility (and could be corrected in software). I'll know next week when the tester arrives.

author: Fungus
author_rank: Super Contributor
timestamp: March 05, 2023, 12:26:35 am
content: Quote from: smbaker on March 04, 2023, 11:58:41 pmTurn it up 10 degrees.(The Wattage only kicks in with the thermostat and maybe you're teetering on the temperature brink)PS: What temperature did you dial? Whatindicatedtemperature does the solder melt at? Did you do the cold-start test?

author: DimitriP
author_rank: Super Contributor
timestamp: March 05, 2023, 12:42:37 am
content: Quote from: IanB on March 04, 2023, 11:19:55 pmThere you go!

author: sonpul
author_rank: Regular Contributor
timestamp: March 05, 2023, 08:24:38 am
content: To calibrate the induction soldering station, I use a thermocouple and Brymen and use a PT100 temperature sensor. Both methods give excellent, accurate, similar results. I make measurements in a small drop of solder on a wooden platform.

author: jonpaul
author_rank: Super Contributor
timestamp: March 05, 2023, 04:05:49 pm
content: use type K thermocouple #30 AWG Kynar or Téflon jacket.Must be welded,bead,type.Allow well tinned tip to stabilize in free,air, horizontal.Imerse TC bead on to center or tip, add solder, 63/37, eutectic NOT lead,free.after 60,sec read TC.Accurate and repeatableJon

author: smbaker
author_rank: Regular Contributor
timestamp: March 18, 2023, 11:51:06 pm
content: Okay, I have some results after finally receiving my "soldering iron temperate tester". I purchased one of the knock-offs of the FG-100. This tester is utter rubish. Poor build quality, some difficulty getting repeatable results, and thermocouples that fit loosely in the tester. It's what you expect from a < $20 knockoff. Instead, I switched to jonpaul's method of putting the iron horizontal and immersing the TC bead into a blob of solder on the tip. Doing this I received repeatable reliable measurements.At 370 degrees:* Pace with 1/64" conical tip: 354 degrees.* Hakko with factory (1/16" ?) wedge tip: 350 degrees* Hakko with aftermarket 1/64" conical tip: 298 degreesWhen I started this thread, I probably using the Hakko with that aftermarket tip as I had already set my mind on returning the Hakko. My original intent had been to compare the performance of the factory and aftermarket tips and although I have a Hakko 1/64" factory tip as well, I did not test it, as I did not want to open the package containing the tips.Scott

author: jonpaul
author_rank: Super Contributor
timestamp: March 19, 2023, 01:49:56 am
content: Rebonjour Cher Monsieur SMBaker,Bravo pour votre efforts thermocouple.We have had consistent results on solder iron tips,as well as,solder pots,,for both leaded,,and RoHS solder since,15 years.We used Omega K TC, plugs,and cables, and Keithley and,Fluke types K TC meters.We calibrated the meters,and TCS with ice,bath and boiling water.Important to select a thin guage,TC,wire eg,#30AWG, and insulation rated for solder temps like Kynar, Téflon, etc.DIY TC must be welded or braised.We get very consistent tip temps.with both old Hakko 926, 936 and our 1992 Metcal SmartHeat SP-200 500 kHz solder stations with Metcal handles and tips.As we,have several of each type iron, we have both large,chisel tip and small cone tip irons on the bench.We use wet sponges to clean off dross and original Hakko and Metcal holders.Remarkably we,have yet to change a tip in decades....but we are doing bench work perhaps once a month nowadays.....Hope this mémoire is of interestWishing you an absolutely fantastic weekendJonpix one bench Tektronix scopes 7000 plug-ins, Yokogawa digital scope and in background the Hakko and Metcal irons....

author: Arts
author_rank: Regular Contributor
timestamp: March 20, 2023, 01:21:04 am
content: Quote from: smbaker on March 04, 2023, 10:27:42 pmYes indeed, I couldn't agree more, it's a horrible system. I have an 888D (genuine) myself, but other than the user interface, I think it's a great little station.One thing to remember is that if you get your button-pushing wrong, you can end up in calibration mode re-setting everything, thinking you are just changing the temperature. Then, despite what the display says, your tip temperatures will be way off. I know this from personal experience, and it had me chasing my tail for an embarassing amount of time until I figured out what I'd done.The included instruction manual made no mention of this, and I only found that information when I downloaded the "complete" manual from the Hakko website. I believe (??) you can restore the unit to factory default calibration using that manual.Cheers,Art

author: JimKnopf
author_rank: Frequent Contributor
timestamp: August 20, 2023, 07:07:38 pm
content: I also bought recently a FG-100 clone from ali like @smbaker mentioned in this post.https://www.eevblog.com/forum/testgear/measuring-the-temperature-of-a-soldering-iron-tip/msg4765436/#msg4765436The reason was i managed to get some parts in my JBC CD-2SQE exploded while soldering on a board connected to main power line but switched off. Unfortunally is was one of the usual single line switches, so live line and mains earth from soldering station meet in my JBC board. The device was still starting and displayed temp values but could not heat the tips. I repaired some parts using schematics i found here on eevblog (https://www.eevblog.com/forum/testgear/jbc-soldering-station-cd-2bc-complete-schematic-analysis/). After that it heats up but i was not sure if the temperature was correct. I've got a Keithley DMM6500 and a K-Thermocouple temperature sensor for it. It's a very accurate measurement. But it's tricky to find the right angle/position for a correct reading with a solderiron tip. So i gave the FG-100 a try.The FG-100 clone shows very low temperature. I mean 3% difference would be ok, or maybe 5% is accetable. But it's missing around 40 to 50°C. I tested with a Pinecil V2, JBC CD-2SQE and a JBC clone, my new Jabe UD-1200 PRO (only T210 handle).The repaired JBC CD-2SQE was set to 330°C which i measured exactly with the Keithley DMM6500. The FG-100 clone showed something around 282-284°C max.The Pinecil was set to 410°C which i measured exactly at this temp with the Keithley DMM6500. The FG-100 clone showed something around 372°C. The FG-100 looks like useless. It's total crap. I opend the device because i read some could be calibreated. Seems i got the cheapest one on earth with missing parts. There is a printed mark "VR1" with 1K on the PCB. But the parts in this area are missing.Anyone figured out what resistors are needed to get the calibration circuit to work? Looks like 2 resistors with unknown values are missing.

author: wraper
author_rank: Unknown
timestamp: August 20, 2023, 08:35:05 pm
content: Quote from: JimKnopf on August 20, 2023, 07:07:38 pmIt looks quite straightforward. You need to remove R1 and populate R10, R9 and VR1 which apparently should be 1k. You should select R10 and R9 in a way so total resistance in the middle position of VR1 is about the same as R1 which is 9.31K. So you could populate two 4.3k Resistors + 1k multi turn potentiometer. In a case if you don't have enough adjustment range to get proper reading, replace one of the resistors to a little bit higher or lower value. Of course there is no guarantee it work correctly as normally there should be separate adjustments for gain and offset but you can try and see if it gives an acceptable result.

author: KungFuJosh
author_rank: Super Contributor
timestamp: August 21, 2023, 02:45:33 am
content: Two things to also consider regarding accuracy: the tip sensors are disposable, and can only accurately measure a limited amount of times. It is also sometimes helpful to use a drop of solder as a heat bridge.

author: DaneLaw
author_rank: Frequent Contributor
timestamp: August 21, 2023, 04:15:00 am
content: Tried some years back to take soldering iron temp-readings with both thermal & these surprisingly cheap FG100 clones.Overall pleasantly surprised about these 8 dollar Chinese clones on eBay, though it's like almost a decade back.Were both fast and surprisingly accurate for the price, the biggest con was misplacing the spare sensors that came bundled.(no idea where mine is)The blue unit at the left (FG-100)..though soldering irons on thermal-macroshots is more helpful to sense variables on the heating area' than to give tangible ref values.Seek 2017

author: wraper
author_rank: Unknown
timestamp: August 21, 2023, 04:22:20 am
content: Quote from: KungFuJosh on August 21, 2023, 02:45:33 amNot just helpful, a blob of solder on the tip is mandatory for accurate measurement.

author: KungFuJosh
author_rank: Super Contributor
timestamp: August 21, 2023, 04:24:37 am
content: Quote from: DaneLaw on August 21, 2023, 04:15:00 amSearch for Hakko 191212 and you can get replacements.Direct from Hakko:https://hakkousa.com/191-212-replacement-sensor-for-fg-100b-100-101-tip-themometer.htmlI think the generic sets are under $10 on eBay.

author: wraper
author_rank: Unknown
timestamp: August 21, 2023, 12:44:15 pm
content: Chinese sensors should be just fine, It's quite difficult to screw up when making type K thermocouple. On other hand, screwing up with the device is much easier, especially when you cannot be bothered with calibration and don't care about cold junction (room temperature) compensation.

author: AmnevaR
author_rank: Contributor
timestamp: August 21, 2023, 01:54:26 pm
content: Quote from: KungFuJosh on August 21, 2023, 02:45:33 amYou are absolutely right.I have to measure temperature of soldering irons at work once a month.I want to add that those sensors are crap. I can't get more than 20 measurements out of one sensor. The temperature reading starts jumping all over the place when the sensor starts to fail. Of course, I didn't overheat them - one measurement is no longer than 10 seconds.We bit the bullet and bought a few of these "better" AS5000 sensors:https://uk.farnell.com/hakko/as5000/long-life-sensor-soldering-thermometer/dp/3585821I have already taken several hundred measurements with one sensor without any problems.If you want to frequently measure temperature of soldering irons I would recommend to get a better sensor and save money in a long run.

author: jonpaul
author_rank: Super Contributor
timestamp: August 21, 2023, 02:18:14 pm
content: Most accurate is type K thermocouple, thin guage wire , Fluke temperatur meters like model Fluke 51 or Kiethley 871.Jon

author: JimKnopf
author_rank: Frequent Contributor
timestamp: August 21, 2023, 03:25:39 pm
content: @AmnevaRQuote from: AmnevaR on August 21, 2023, 01:54:26 pmFeels a bit like putting lipstick on a pig, i paid 40 Euro, double the price of the FG-100 clone, but i will try the result for educational purpose.

author: colorado.rob
author_rank: Frequent Contributor
timestamp: August 21, 2023, 04:15:08 pm
content: Somewhat off-topic but when my X-tronic died, I opted for a Thermaltronics TMT-9000S-1 after hearing Chris talk about his Thermaltronics soldering iron with Dave on The Amp Hour a couple years back. Never looking back. That thing is freaking awesome.

author: JimKnopf
author_rank: Frequent Contributor
timestamp: August 21, 2023, 06:05:48 pm
content: There is one thing i dont understand with the K-Type Thermocouple. At room temperature the values of my devices is nearly the same. In the first picture you can't see the K-Sensor from DMM6500 between the FG-100 and the Hygrotemp24 device to have all sensors together as near as possible.I found the K-Type Thermocouple reference tablehttps://reotemp.com/wp-content/uploads/2015/12/type-k-thermocouple-reference-table.pdf. But the values doesn't match. The Keithley DMM6500 measures nearly 0 mV at around 23°C. But the reference table says 0 mV should be around 0°C. I attached some examples i measured with the DMM6500 sensor and the solderiron. Both K-Type sensors, the one from the FG-100 clone and the one from the DMM6500 have 0mV at around 23°C.Maybe someone can explain this offset? There is a temperature setting in the DMM6500 menu for the device temperature. It's set to 23°C.

author: jonpaul
author_rank: Super Contributor
timestamp: August 21, 2023, 06:45:48 pm
content: see cold junction compensation for thermocouples.Most high end meters have a built in TXC ><temp function and CJ compj

author: wraper
author_rank: Unknown
timestamp: August 21, 2023, 06:59:22 pm
content: When there is no temperature gradient over thermocouple it outputs no voltage. Thermocouple does not measure absolute temperature, only temperature difference.

author: IanB
author_rank: Super Contributor
timestamp: August 22, 2023, 01:49:25 am
content: Quote from: JimKnopf on August 21, 2023, 06:05:48 pmIn the same way that voltage is measured as the difference between two points, thermocouple temperatures are measured as the difference between two junctions. Every "thermocouple" is actually two thermocouples, a reference junction and and a sensor junction.Hence, the reference table says that 0 mV should be measured when thedifferencebetween the two junctions is 0 deg. C (not 0°C absolute temperature).Thermocouple instruments have the reference junction inside the case, and this is thermally adjacent to (or bonded to) a reference temperature sensor such as a thermistor or solid state temperature sensor. The instrument uses the independently measured reference temperature along with a compensation table or algorithm to deduce the actual temperature of the probe based on the voltage difference between the two junctions and the actual reference temperature (which is typically room temperature, but room temperature can vary).

author: bdunham7
author_rank: Super Contributor
timestamp: August 22, 2023, 02:07:03 am
content: Quote from: smbaker on March 18, 2023, 11:51:06 pmThe FX-888 is a decent tool with Hakko tips. The nice tip selection is one of the main features. I prefer the beveled conical style and the 1/64 conical is generally pretty useless. Aftermarket tips on these typically just totally suck. I can't imagine you could get anything done with an aftermarket 1/64 conical if they're anything like the junk I got.

author: AmnevaR
author_rank: Contributor
timestamp: August 22, 2023, 05:38:39 am
content: Quote from: JimKnopf on August 21, 2023, 03:25:39 pmDefinitely. We also use the FG-100 clone. The sensor makes a big difference.

author: DaneLaw
author_rank: Frequent Contributor
timestamp: August 22, 2023, 06:36:07 pm
content: The crude FG100 sensors are so cheap that it's knocking on the aspect "test & throw-away after use" at around 10 cents each.Aint it like 1 buck for a 10-pack of these non branded [191-212] FG100 sensorswhile AS5000 sensor are around 40 US for 1pcs, though haven't compared them, as the non-branded 191-212 seemed to do the job, quite well.//More or less.. 2 bucks (US) incl. 25% VAT for a pack of 20https://aliexpress.com/item/1005005573185264.html?and 70 cents for 10pcshttps://aliexpress.com/item/1005004984843146.html?

author: JimKnopf
author_rank: Frequent Contributor
timestamp: August 23, 2023, 04:29:09 pm
content: @AmnevaRI give 100 out of 100 points for this very good recommendation. I didn't expect that. I didn't change the parts on the PCB. I was waiting for the 40€ Hakko Temp-Sensor which arrived today. Same setup. First the old one, then the new one. It's very accurate reading only because i changed the Temp-Sensor.Thats what i call usable.

author: Jono434
author_rank: Contributor
timestamp: November 03, 2023, 07:18:44 am
content: I've been out of the game for a few years but have been doing a lot of reading lately, looking to get back into it again and do some circuit modding and soldering etc.With the Hakko stuff and the clones.. I've been sensing a very strong theme. The Chinese kits, or clones generally work pretty well. Sometimes safety is dodgy and you might need to tidy that up. Sometimes there is random variations and you never know what you are going to get. But one thing for sure is that you need to pony up for the expensive hardware. In terms of using real Hakko solder tips, or in this case.. real Hakko sensors. The Long Life one.. AS5000.At first glance it seems strange to spend so much but as JimKnopf and AmnevaR showed, it's well worth it. They are expensive but you actually get something that works well. One thing I'm unsure on is the method of using solder while measuring.Do you guys all do this, or is it considered optional? It's hard to find concrete info on this, it seems a niche topic and open to personal preference. After measurement do you desolder the sensor with wick or a pump or just leave it on? I guess it doesn't matter much either way, but if using AS5000 you are going to want to preserve the life of it as much as possible.It does make sense though.. to recreate the same conditions that the soldering iron will be put under in real world usage.

author: KungFuJosh
author_rank: Super Contributor
timestamp: November 03, 2023, 03:38:42 pm
content: Quote from: Jono434 on November 03, 2023, 07:18:44 amThe specific condition you would be recreating is using solder as aheat bridge. You can try testing the temp dry, and with a drop of solder as a heat bridge, and see how the temps compare. The solder shouldn't really stick to the sensor; if it is, you left it there way too long.

author: TomKatt
author_rank: Frequent Contributor
timestamp: November 03, 2023, 06:00:58 pm
content: Maybe it's me, but I've never relied on trying to dial in any specific temperature on the station... It seems pretty straightforward to just get a feel for how the solder is flowing (or not) and turning the station up or down as needed. I've never damaged a board or component from overheating.Granted, I'm just a hobbyist and while I can appreciate the importance of accurate solder temps in a commercial environment, it doesn't seem to matter that much for home use.And probably why I still like my old analog Weller with a dial - a twist is easier than a button dance.

author: KungFuJosh
author_rank: Super Contributor
timestamp: November 03, 2023, 07:30:17 pm
content: It matters. Especially if you have a digital station with the temperature drifting at some point. Lots of things are temperature sensitive. If you have the correct temperature dialed in, you can make a quality solder joint quickly without causing damage. If the temp goes low, and you're not aware, you can wind up lingering for too long and either cause a bad joint or damage what you're soldering.

author: AmnevaR
author_rank: Contributor
timestamp: November 04, 2023, 04:33:28 pm
content: Quote from: Jono434 on November 03, 2023, 07:18:44 amSome solder will eventually stick to the sensor and the flux from the solder will evaporate and leave a nasty residue. Just add more fresh solder and immediately take it out with a clean soldering tip. Clean the the sensor from flux residue with isopropyl alcohol if needed. No worries.

author: joeqsmith
author_rank: Super Contributor
timestamp: November 04, 2023, 05:25:55 pm
content: I used Dave's Brymen BM235 to measure mine. Seemed to match up.

author: artag
author_rank: Super Contributor
timestamp: November 04, 2023, 05:59:50 pm
content: I have (or had, I don't remember if I still have it) a Weller tip temperature measurement system. It's surprisingly complicated.The sensor, according to the manual, measures thermal flow. I'm not sure how it does that but it's something like a thermocouple so may actually detect zero temperature difference between the two sides : as wraper says, this gives 0 volts out.This is combined with a normal adjustable iron with the sensor embedded in the tip. The temperature is adjusted automatically for zero heat flow and when that occurs, the measured tip is the same temperature as the exciter tip. It's like the potentiometer null method of measuring voltage, but for temperature.The idea of all this is to measure temperature without loading the object - something that is only achieved if the null sensor is sufficiently sensitive. But presumably Weller thought it usefully better than the smallest thermocouple available to them.The thermal photograph measurements should be as good, but only if the surface emissivity is known.