Hi - I have a Hakko 936-12 soldering iron - and I think it has come time for me to get a tip better suited for surface mount soldering, as it seems that about half of the soldering I do nowadays is surface mount. But what kind of tip should I look for? I found this website:
which has many different tips listed - but I don't have the slightest clue what kind to get. Any pointers?
Also - does anybody have any good ideas as to where to purchase Hakko tips in the USA? (that place has too large of a minimum order for me). Thanks!
I recently had to deal with this issue. The tip that worked well for SMDs was the smallest radius (most pointy) tip I could buy, which had a radius of 0.2 or 0.3 mm, as I recall. The importance of that is that it minimizes the contact area while soldering a joint, which makes it easier to leave solder as determined by the end-cap and pad rather than how the tip was pulled away. It also reduces the tendency to pull the part as the tip departs. (Although you likely have to get the part glued or clamped anyway, reducing that force can make clamping simpler or allow a weaker glue.)
The local Fry's carries them here. (Puget Sound, Washington, USA)
The problem with the very very pointy tips is that they also tend to be LONG and gently tapered down to that fine point. It's very difficult for the iron to keep the end of that tip hot. I've had better luck taking a chisel tip and filing it down to a sharply conical point.
This has never been an issue in the SMD work I have seen and overseen. It might become an issue if you use the fine pointed tip for soldering 14 AWG Romex or the like. But for SMDs, there is enough heat near the point to bring any normal sized SMD terminal, pad and paste instantly (as far as can be perceived) up to reflow temperature. This goes for SOT-89 mini-power packages as well.
That is surprising considering that most tips are iron plated these days. Perhaps you never used such an abused tip long enough to notice it being eaten away hollow where you had removed the protective iron coat.
It's a big problem for surface-mount electrolytics (where you can only get your iron at one end of the pin; most of it is under the package), sometimes for SMD HC49 type crystals, and also for power pins on micros (at least, if the board is laid out properly). Those power planes suck down heat amazingly. Also for gull-wing packages that have those special thermal management tabs (I'm thinking motor driver ICs here).
I didn't say anything about the longevity of such a tip. Sure, it deteriorates rapidly and needs to be refiled once a week or so, and it does eventually need to be discarded. But that's paid off totally in the number of devices I don't damage by waving a lukewarm three-foot lance in their general direction. Yes, I'm exaggerating.
If someone made a sharp, short bullet point tip for my solder station (Loner 951SX), I'd use it. Actually, maybe Edsyn does - but it's cheaper for me to buy 100 tips of one size and file down a few.
The temp sensor is not at the tip of the iron. The more thermal resistance between the work area and the temp sensor, the less accurate your temp setting is (w.r.t the temp the actual joint reaches). Yes, you can set your iron's thermostat to 1200F and hope that this translates to a tip temperature of 650F when it's touching certain sorts of joints, but it's much safer simply to remove some sources of inaccuracy.