Alioth's Journal: Ding Dong the Witch is Dead

Well, the Cthulhu at work is out of a job. Yay! To be honest she's not been bothering us too much of late, having the hospital as her latest toy to bother, but she failed to get re-elected this week. There was much rejoicing. Unfortunately, the damage she did is already done - she got rid of our ablest manager because he dared to disagree with her...by underhanded tactics - making his job position 'redundant'. None of us were surprised when 18 months later the job suddenly existed again. It all started going wrong for her when she was accused of bullying and assault by a DHSS worker, which seemed rather exquisitely timed...

Anyhow enough of work. This week I got some grey goo. No, not Prince Charles's nanobots that will turn the earth into grey goo, but a small syringe of grey goo. The goo in question is solder paste - a suspension of fine solder particles and flux in some kind of solvent. I got it to see if it made assembling the Spectrum ethernet cards any easier - since I designed it with a lot of fine pitch surface mount chips. And it's been a revelation - the road to Damascus. Lay a fine bead of stuff down (by hand I can't ever hope to put blobs precisely on each pad), place the chip, then use my trusty paint stripper gun(!) as a hot air source to reflow. The paint stripper gun works rather well - on the low setting it's 260 celcius and the blast of air is relatively gentle and won't blow chips around. Peak reflow temperature is 260 celcius. I fashioned a smaller nozzle out of aluminium foil so I could direct the air over a smaller area, I can do a chip at a time with it quite easily. The W5100 chip still turned out to be the hardest - going from 0.5mm to 0.4mm pin pitch seems to make things 100 times harder (in fact after visual inspection seemed to show everything was OK, it turned out not to be the case - there's at least one disconnected pin and it only has to be the most critical. But it's late and I'll probably screw it up if I try to fix it tonight, so I'll leave it tomorrow). But other than that I'm really taken by solder paste and hot air for soldering SMD - it's much neater than using the soldering iron, and leaves far fewer 'bridges' between pins (again, solder wick turns out to be incredibly useful). I'm still learning how best to use it though, it only seems to need really tiny amounts and I tend to put too much down.

Before I got busy with the paste though, yesterday I thought the weather was calm enough to take my Honey Bee CP2 RC helicopter down to a secluded beach and give it a really good work out. I chose Fleshwick Bay, because hardly anyone goes down there, it's quite sheltered, and... hardly anyone goes down there - so if I crashed there would be hopefully no witnesses to embarrass me.

When I got there there was more wind than I expected. Worse of all it was coming *down* the cliffs. Downdrafts, I thought, I probably ought not to fly. But against my better judgement I thought I'd take a sniff and see what it was like. That was the wrong move. The air was extremely turbulent and the downdrafts were actually quite strong. I lurched around the sky for about a minute, and decided to bring the heli back to me when I felt a strong gust of wind coming straight down the cliff...seconds later, I crashed - the heli landed upright on its skids but very hard, and the main rotor chopped the tailboom off, and then the heli rolled on its side and did the 'death thrash' till I managed to kill the power. Walking over to it, I saw that the pretty indestructable plastic blades were actually quite destructable - both shattered, and the tail had been chopped off. Also a ball link from the mixing arms had broken off too.

But this evening when I got home I found a five pack of wooden rotor blades had arrived, so I fixed the heli with superglue :-) The tail boom isn't exactly straight, but it is at least in one piece now. The superglue also worked for reattaching the ball link (which remained within its linkage, fortunately, or it'd have been lost forever). The main motor seems a little tired now, but other than that the heli is flying perfectly after its trauma. Of course I had to fly off three batteries worth to check, sadly though it was far too windy to fly outside so I had to make do with cruising around the living room.

Good luck

[tqft]

I can't even solder up a headphone plug properly. (2 down total cost so far $4.50). And no I can't find a 2.5mm plug on a headphone set.

Even bought a hands free magnifier headset to help me see what I am doing.

Good beginner soldering instructions? Any recommendations out of this lot?
http://www.google.com/search?hl=en&client=mozilla&sa=X&oi=spell&resnum=0&ct=result&cd=1&q=beginner+soldering+instructions&spell=1 [google.com]

Re:

[Alioth]

I *hate* soldering connectors.

Probably the best thing to have if you're forced to do it, though, is a set of 'helping hands' - basically a thing with a heavy base and metal arms with crocodile clips. These will hold the wires in position so you can use both hands to do the actual soldering.

The trick is that all the things you're trying to solder must be up to temperature, otherwise the solder just rolls off. So for connectors, I get them in the 'helping hands', put the tip of the iron to the connector and w

Re:

[tqft]

"The trick is that all the things you're trying to solder must be up to temperature"

Ah he says

"otherwise the solder just rolls off"
having seen that

Thanks

And I thought it was my eyesight on something that small leading me astray.

I flicked through a few of the links and had a look + your advice.

So heat the wire and a little solder.
Heat the connector and a little solder.
Heat both quickly and hold together.