Hacko 888D Handle Free Play Between Ceramic Heating Element to Tip?

[dannyf]

Genuine Hakko tip.

Looks nice.

Just don't bank on it being genuine: unless you go directly to Hakko, chances of your running into a Fakko are high, especially from an unauthorized reseller.

[SuzyC]

Ok, found a genuine distributor of Hakko and the tip I want at the same price as IdaFruit! Its on order.

Hakko Soldering Tip: T18-C2 Hoof - For Lead or Lead-Free Use

[SuzyC]

BTW, thanks a million to everyone! I am kinda ready to hoof it on to a new post.

I have a good transformer and case and soldering iron holder from the kaput old soldering station made by Skylink, now the idea is to get it to work with the new Hakko 8801 handle.

The old handle used a thermocouple, the Hakko uses a PTC thermistor, not a pop-in replacement, although I can snap off the center pin of the 6-pin DIN connector and it will plug right in the old station.

I know just one thing and maybe that is all I need to know. When the Hakko sensor measures between 100 and 110 ohm, its just at the right temperature for soldering!

Possiblities:
(1) make a voltage divider that biases the PTC thermistor in the Hakko element and detect when the resistance is 100 ohms, bingo I am at the right temperature and I can turn off the TRIAC until the temperature falls. I detect the temperature(voltage corresponding to 100-0hms) with a LM393 comparator or even an op-amp.
(2)Take the output of the voltage divider in (1) and feed it (through a calibration adjust pot) to the thermocouple input connections that went to the old handle, and all I got to do is match the same voltage and I can even see the old station's bar-LEDs temp indicator to show me the temperature settubg and I can then also use the same pot on the front panel to adjust temperature???

The only fly in the ointment(ok, soldering paste) is that the output of a PTC thermistor is exponentially changing, while the output of the old thermocouple linearly changes as a scaler with temperature.

[dannyf]

It is not difficult to make a universal adapter that takes either PTD or thermocouples as tempearture sensors. One opamp will do.

[tautech]

I found a tip on AdaFruit, seems like it might be what I need to work work, Genuine Hakko tip.

What do you all think? It this a good price and a good place to buy it?

Watch for tips that step down quickly to the point, their ability to conduct heat is compromised by this sort of design. Slender taper like the one pictured are best.
I have ~ 4 that see the most use, 4 mm chisel, 2 mm chisel, knife, and plain pointed fine.
I believe the "hoof" styles are good but as yet I haven't tried or needed them.
The 45 degree knife style are excellent for "wiping" off SMD passives as the can bridge both pads at the same time.

Handles compatibility.
There are 2 main types of elements, you'll have to find the one that suits your station.
I converted a station to suit a cheap easily obtainable handle & I can tell you it was a PITA, but can be done.

2 irons that fit your station is a good idea as you don't have to risk burning fingers changing tips part way through a project.

[SuzyC]

Thanks dannyf,

Easy for you to say, but I don't have a thermometer that will measure the temperature v. resistance to calibrate things. Is it possible to find the temperature v. resistance of the Hakko 888d handle?
If I could get readings of just 50-deg C steps of temp I could interpolate the correct temperature with a MCU for any temperature setting.

I bought a cheap soldering station that works kinda like 6-day old Chinese take-out on a starving stomach, it has an LCD indicator that supposedly indicates temperature, but I don't think it knows up from down.

One thing I do now, with the Hakko handle running at full power, open-loop, it can easily remove an electrolytic radial through hole cap from a 4-6 layer table top PCB ground plane in less than 30-secs, the old station could never do that!

Maybe I can wrap the two handles together with a thin copper sheet and read the temperature of the older handle and write down the corresponding PTC Hakko resistance?

Now I might just try this elegant calibration technique, I got some sheet copper, just try to not burn my fingers, char my workbench and not burn down the house.

I have three readings so far:
21-deg C                                                                59  ohms
Nice Lead/Tin 60/40 Soldering Temperature 100-110 ohms
Full Power Open Loop Nuke Meltdown                 238 ohms

[dannyf]

How you approach it will depend on  your needs.

For me, linear approximation is good enough.

I have three readings so far:
21-deg C                                                                59  ohms
Nice Lead/Tin 60/40 Soldering Temperature 100-110 ohms
Full Power Open Loop Nuke Meltdown                 238 ohms

The meltdown is likely in the 450-475c range.

You can probably google the melting point for 60/40 solder.

Or you can always get a thermocouple + temperature gauge to measure it.

Again, it all depends on how picky you want to be.

[SuzyC]

Thanks dannyf,

It seems that solder "begins" to melt at a certain temperature, then there exists  a fairly large temperature spectrum of higher temperatures in which the solder remains "plastic/muddy" and finally there is a free-flowing soldering temperature that you instantly recognize when you apply a piece of your favorite solder on the tip and it melts just right.
It is not so easy for me to get a thermocouple+gauge.

My tying together of two irons is the closest thing I have to achieve calibration.

Can anybody post a few other Hakko 888d sensor resistance v. temperature readings?

[dannyf]

It is not so easy for me to get a thermocouple+gauge.

That's life, right: you have to make difficult decisions -> do I make do with what I have, knowing that it is imprecise? or I wait for others to make precise measurements, knowing that while such measurements are precise to their handles, they may not be precise for my handle?

It just isn't going to be perfect, either way.

[tautech]

Thanks dannyf,

It seems that solder "begins" to melt at a certain temperature, then there exists  a fairly large temperature spectrum of higher temperatures in which the solder remains "plastic/muddy" and finally there is a free-flowing soldering temperature that you instantly recognize when you apply a piece of your favorite solder on the tip and it melts just right.
It is not so easy for me to get a thermocouple+gauge.

My tying together of two irons is the closest thing I have to achieve calibration.

Can anybody post a few other Hakko 888d sensor resistance v. temperature readings?

When I did one I had a TC for my DMM and connected with a wire clip.
You'll find tying irons together will not work, there is too much thermal mass.
But if you extract the element and just use that as the sense it might work. 

[SuzyC]

Thanks tautech!

Genius! Why didn't I think of that??

I can dissemble both irons down to the heating element. I could wrap both heating elements together with bare #22 wire and then slide a piece of copper tubing over the both of them to form a fairly isothermal compartment and then read the Hakko resistance versus the "calibrated" temperature reading on the LCD readout of my cheap Chinese soldering station!

I don't have any high-temp heat-resistant material to cover the mating heating element pair, so I can hope a piece of copper tubing would serve to keep them near the same temperature and insulate the elements from having different temperatures due to air cooling.

[IanB]

It seems that solder "begins" to melt at a certain temperature, then there exists  a fairly large temperature spectrum of higher temperatures in which the solder remains "plastic/muddy" and finally there is a free-flowing soldering temperature that you instantly recognize when you apply a piece of your favorite solder on the tip and it melts just right.

That depends on the solder. 60/40 solder will behave that way, but eutectic 63/37 solder will melt instantly and solidify instantly. That's a reason many people prefer 63/37 solder. There is less chance of wiggling the joint while the solder is only half solidified.

[SuzyC]

Thanks IanB for your comment,

Unfortunately I didn't have any eutectic solder on hand.

The reality of it all is that most soldering temperatures can be closely approximated by watching the melting behavior of the solder and if I know the one temperature knob position setting that melts 60/40 just about perfect, then this is just the one dot on the panel that the temperature adj. pot  adj. knob needs to point to, and  then a slight twist a little to  left for delicate work, a little twist to the right for Pb-Free or full max power to lift defective electrolytic caps from 4-layer PC Motherboard ground plane.  As long I can buy Pb/Sn, I won't ever touch lead free solder with a hot iron for repair or build.


By strapping the two elements together, I discovered that the resistance increases very close to 2.3-ohms for each 10-deg C rise, very linear in the tin/lead soldering temperatures. These temperatures were taken quickly and not averaged,  and reversing the temperature readings from 450 to 90 resulted in 5 ohms difference, probably because I am only transferring the heat and measuring the temperature at the part of the element that reaches into the soldering tip of the Hakko, but the older iron may have storage of heat in the mass of a much larger diameter element. If allowed a minute or two to settle, the readings tend to match the temperature rise measurements within -0, +3 ohms. So..my best guess:  +/- 5 ohms +/- 20-Deg might be the worst case error. Close enough to melt my metal!

Temp  C            RTC ohms
  22                    60
160                    80
170                    82.8
180                    85.8
190                    88.1
200                    89.2
210                    91.5
220                    93.4
230                    95.8
240                    97.6
250                  100.2
260                  102.6
270                  105.0
280                  107.3
290                  109.4
300                  111.5
310                  114.7
320                  117.4
330                  119.1
340                  121.3
350                  123.9
360                  126.1
370                  128.0
380                  130.0
390                  133.0
400                  135.0
410                  138.0
420                  140.0
430                  142.0
440                  144.0
450                  146.0
http://www.ebay.co.uk/itm/181625520082
New HAKKO FX8801 Soldering Iron Handle for FX888 FX888D Solder Station 26V/65W  Approx USD $24 w/shipping int. mail
Pins 1-2 (clockwise view of male connector) heater element approx 5-ohm DCR
Pin   3   ground
Pin  4-5 RTC
pint 6 (located in center) NC
Reaches soldering temperature within 30-secs with a 24VAC 3-Amp AC transformer open loop.

[dannyf]

Code: [Select]

Temp  C            RTC ohms
180                    85.8
190                    88.1

60/40 solder melt between 183-190C, and you had previously measured the PTD resistance at that temperture to be 100 - 110ohm, vs. 85 - 88ohm now.

Assuming that the previous data is accurate, you have a temperature sensitivity of 2.8ohm/10C.

[SuzyC]

dannyf,

A spot check of my raw data shows that across the range of measurements,  it is very close to delta 2.25 to 2.30 ohms/10-Deg C rise over the temperature range of 160-Deg C to 450-Deg C.
Solder(60/40) started to just melt and be plastic at that (approx 94 ohm) lower temperature, but the 100-110-ohm (105 Avg) resistance was the "sweet spot." for full liquidity.