It takes 5 seconds to heat up from cold start as well. Thing just piles out heat when you need it. Just did a couple of SOIC ICs onto carrier boards. Much nicer than the weller.
Ordering a brush and some kimwipes and I’m sorted 
Yeah, these use a different thermal regulation process; it's entirely chemical based on the curie point of the metal slug which is heated by induction rather than a resistive element. As a result, the response is instantaneous, as opposed to the traditional "apply tip, tip loses heat, thermal sensor creates call for more heat, heating element heats up, thermal threshiold is reached, sensor calls for cut heat" closed loop system; the thermal regulation is a product of the physics of the metal slug, so all that goes away.
The big MX units like mine incorporate another feature as well; this is what the "SmartHeat" feature is all about:
The inductor is powered by PWM regulated HF AC; as such the entire tip is sensitive to changes in the metal mass at the tip. The control board monitors this loading, and increases the PWM Duty Cycle in response at the instant the tip contacts anything metal, so the entire "Temp at tip drops, sensor calls for more heat, heater heats up" part of the loop is bypassed.
As you correctly noted, it simply applies the heat faster.
Looks good, can see why it's good on ground planes, it's got lots of metal so should have very good thermal clout when you need it. [emoji106]
The type of Metcal BD139 has picked up is a bit of a hybrid and operates slightly differently from the 'classic' Metcals. The principle on all the Metcals is to move the point of thermoregulation as close to the work as possible, they don't rely on thermal mass but speed of response. My SP200 takes tips like this:
which is 108mm long, 6.25mm wide and weighs all of 7.25 g and includes the entire heater, curie point thermostat mechanism, actual soldering tip and a two pin connector. It's 'only' rated at 30W, but the heating and regulation mechanism is concentrated in the last inch so that 30W is delivered to exactly where it is required. It pisses all over the conventional 50W temperature controlled iron I was using beforehand by a factor of two or three in terms of heat delivered into the workpiece.
The type BD139 has got separates out the (induction) heating coil into the hand-piece and uses a separate tip that still uses the curie point regulation mechanism. it isn't quite as fast to respond as the heat has to travel slightly further so it needs a bit more 'meat' to even the response out, but it's still much faster than any conventional temperature controlled iron.
The most comforting thing about the whole way Metcals work is that it's physically impossible for them to overshoot their temperature setpoint more than a tiny amount so there's much less risk of cooking the part you're working on. Since I've had the Metcal I haven't lifted a single pad in situations where my older iron would have destroyed the pad in short order but probably would have still failed to deliver enough useful heat to let me get the part off. I also get much less cooking flux into a brown mess when I have to dwell on a part to get it to flow properly.
Interesting note on how the different tips work; this explains them being able to bring the cost point down to where it's a more reasonable ecosystem for the small shop. I wonder how that design change affects the sensitivity of the inductive load sense part of the SmartHeat feature... from bd139's notes, it's still pretty quick.
That said... speaking as someone whose primary use is repair rather than assembly work, I still prefer the thinner profile of my T12 & MX tips. Another thing I prefer about the MetCal in particular is that when tinning/soldering wires, there's a lot less of the cheap insulation bubbling/shrinking back where you have to stop, trim the burnt stuff off, then tin again before you solder to not have a blobby mess.
Myself, I still prefer the MX overall... if you shop carefully, you can buy a working, guaranteed MX-500P for $50-75 pretty much any time on fleaBay, then add a new MetCal MX-RM3E handle for ~$110, or a new Thermaltronics SHP-1 for ~$80, add a couple tips for ~$20 each, and you're all in for around $200. You have the part you interface with, the handle and tip, brand new... and the MX500 power bricks are built like a effing TANK; they're made to run 24/7 in an industrial environment. If you get one that's working, odds are its going to keep working a good long time.
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If you shop carefully for used handle and tips, you can get everything for more like $100-150, and then you only need a stand. if you don't want sleep mode, any stand will do. If you do want it, $40 buys a genuine MetCal or Thermaltronics stand with the magnet built in. Otherwise, you can do like I did and just mod a speaker magnet into your favorite stand.
I'm at ~$89 all-in (plus another $8 for the stand which I use for two different stations) for this setup with used STTS-838 1.5mm chisel tip; but that's after having to wrangle with the seller on the handle for selling "busted, fixed up best I could" as "used, working" and getting 1/2 my money back. I had to do some repair on the F-connector to get a reliable connection; that kind of shenanigans is the obvious reason to go with new instead of used for this most crucial part of the system.
You don’t /need/ one but it’s like upgrading a chair leg to a Samauri sword so far.
Honestly I was a bit worried it was going to be a bit meh but I was pleasantly surprised. This is difficult for me as I’m a 100% cynical glass half empty sort of person.
Yeah, that's MetCal; it doesn't look interesting with bright OLED screen, tell time, or beep at you like my KSGER T12 station in the background; it JUST EFFING WORKS.
My grandfather used to describe certain tools... ones where everything but "quality" and "tool-ness" had been pared away, leaving nothing to distract you from your work... as "a joy in the hand". The MetCal MX is just such a tool.
mnem
*back to the grindstone*
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Topic: Test Equipment Anonymous (TEA) group therapy thread (Read 14916324 times)