Author Topic: Measuring the temperature of a soldering iron tip  (Read 10122 times)

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Offline JimKnopf

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Re: Measuring the temperature of a soldering iron tip
« Reply #25 on: August 20, 2023, 07:07:38 pm »
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/#msg4765436

The 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.
« Last Edit: August 20, 2023, 08:41:04 pm by JimKnopf »
 
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Online wraper

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Re: Measuring the temperature of a soldering iron tip
« Reply #26 on: August 20, 2023, 08:35:05 pm »
Anyone figured out what resistors are needed to get the calibration circuit to work? Looks like 2 resistors with unknown values are missing.
It 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.
 

Offline KungFuJosh

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Re: Measuring the temperature of a soldering iron tip
« Reply #27 on: August 21, 2023, 02:45:33 am »
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.
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Online DaneLaw

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Re: Measuring the temperature of a soldering iron tip
« Reply #28 on: August 21, 2023, 04:15:00 am »
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.


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« Last Edit: August 21, 2023, 11:13:10 pm by DaneLaw »
 

Online wraper

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Re: Measuring the temperature of a soldering iron tip
« Reply #29 on: August 21, 2023, 04:22:20 am »
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.
Not just helpful, a blob of solder on the tip is mandatory for accurate measurement.
 

Offline KungFuJosh

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Re: Measuring the temperature of a soldering iron tip
« Reply #30 on: August 21, 2023, 04:24:37 am »
(no idea where mine is)

Search 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.html

I think the generic sets are under $10 on eBay.
"Right now I’m having amnesia and déjà vu at the same time. I think I’ve forgotten this before." - Steven Wright
 

Online wraper

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Re: Measuring the temperature of a soldering iron tip
« Reply #31 on: August 21, 2023, 12:44:15 pm »
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.
« Last Edit: August 21, 2023, 03:40:19 pm by wraper »
 

Offline AmnevaR

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Re: Measuring the temperature of a soldering iron tip
« Reply #32 on: August 21, 2023, 01:54:26 pm »
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.

You 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/3585821
I 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.
 
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Offline jonpaul

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Re: Measuring the temperature of a soldering iron tip
« Reply #33 on: August 21, 2023, 02:18:14 pm »
Most accurate is type K thermocouple, thin guage wire , Fluke temperatur meters like model Fluke 51 or Kiethley 871.

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Offline JimKnopf

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Re: Measuring the temperature of a soldering iron tip
« Reply #34 on: August 21, 2023, 03:25:39 pm »
@AmnevaR

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/3585821
I 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.

Feels 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.
« Last Edit: August 21, 2023, 03:27:33 pm by JimKnopf »
 

Offline colorado.rob

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Re: Measuring the temperature of a soldering iron tip
« Reply #35 on: August 21, 2023, 04:15:08 pm »
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.
 

Offline JimKnopf

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Re: Measuring the temperature of a soldering iron tip
« Reply #36 on: August 21, 2023, 06:05:48 pm »
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 table https://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.
« Last Edit: August 21, 2023, 06:17:35 pm by JimKnopf »
 

Offline jonpaul

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Re: Measuring the temperature of a soldering iron tip
« Reply #37 on: August 21, 2023, 06:45:48 pm »
see cold junction compensation for thermocouples.

Most high end meters have a built in TXC ><temp function and CJ comp

j
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Online wraper

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Re: Measuring the temperature of a soldering iron tip
« Reply #38 on: August 21, 2023, 06:59:22 pm »
When there is no temperature gradient over thermocouple it outputs no voltage. Thermocouple does not measure absolute temperature, only temperature difference.
 
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Offline IanB

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Re: Measuring the temperature of a soldering iron tip
« Reply #39 on: August 22, 2023, 01:49:25 am »
I found the K-Type Thermocouple reference table https://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.

In 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 the difference between 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).
 

Offline bdunham7

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Re: Measuring the temperature of a soldering iron tip
« Reply #40 on: August 22, 2023, 02:07:03 am »
* Hakko with aftermarket 1/64" conical tip: 298 degrees

The 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.
A 3.5 digit 4.5 digit 5 digit 5.5 digit 6.5 digit 7.5 digit DMM is good enough for most people.
 

Offline AmnevaR

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Re: Measuring the temperature of a soldering iron tip
« Reply #41 on: August 22, 2023, 05:38:39 am »
Feels 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.

Definitely. We also use the FG-100 clone. The sensor makes a big difference.

Online DaneLaw

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Re: Measuring the temperature of a soldering iron tip
« Reply #42 on: August 22, 2023, 06:36:07 pm »
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 sensors
while 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 20 https://aliexpress.com/item/1005005573185264.html?
and 70 cents for 10pcs https://aliexpress.com/item/1005004984843146.html?
« Last Edit: August 22, 2023, 07:12:17 pm by DaneLaw »
 

Offline JimKnopf

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Re: Measuring the temperature of a soldering iron tip
« Reply #43 on: August 23, 2023, 04:29:09 pm »
@AmnevaR

I 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.
« Last Edit: August 23, 2023, 05:11:05 pm by JimKnopf »
 
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Offline Jono434

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Re: Measuring the temperature of a soldering iron tip
« Reply #44 on: November 03, 2023, 07:18:44 am »
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.
 

Offline KungFuJosh

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Re: Measuring the temperature of a soldering iron tip
« Reply #45 on: November 03, 2023, 03:38:42 pm »
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.

The specific condition you would be recreating is using solder as a heat 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.
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Offline TomKatt

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Re: Measuring the temperature of a soldering iron tip
« Reply #46 on: November 03, 2023, 06:00:58 pm »
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.
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Offline KungFuJosh

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Re: Measuring the temperature of a soldering iron tip
« Reply #47 on: November 03, 2023, 07:30:17 pm »
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.
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Offline AmnevaR

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Re: Measuring the temperature of a soldering iron tip
« Reply #48 on: November 04, 2023, 04:33:28 pm »
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.

Some 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.   :-+

Offline joeqsmith

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Re: Measuring the temperature of a soldering iron tip
« Reply #49 on: November 04, 2023, 05:25:55 pm »
I used Dave's Brymen BM235 to measure mine.  Seemed to match up. 



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