A tool that is a real boon but rarely justified by most and that's a desoldering station. To be able to desolder a joint (especially a through-hole device) without risk of damage to any of the surroundings (like PCB tracks) or flicking any solder in your eyes is cool.
More for us than you methinks. ;-)
Yes, it is, well done you. ;-)
Cheers, T i m
I've not tried this, but a drip of water just after removing the iron might do it. As someone else pointed out, vibration or joint movement is another approach.
You might be able oxidise the component lead by cooking it at high temperature for a while. That should give a very realistic dry joint, especially if you avoid using flux.
John
When I was in TV design in the 60's, I was told that the ring was caused by the PCB rattling on the conveyor belt before the solder had set. I've found quite a few PCBs with the dry joint rings, usually on heavy leads and tags which could very well have taken longer to set owing to their higher thermal capacity. So the suggestion to rattle the joint before it sets sounds good, maybe using an electric engraving tool? Dave W
Try cutting the track very close to the pin and then putting an overly large blob of solder to hide the cut. That way you're lacking electrical connectivity (which they can find with a meter) and then you can apply as much artistry as you like to producing a dodgy joint without it actually having to be dodgy.
Another approach might be to take some steel wire, get it nice and rusty, and then try to solder that. As long as you have it mechanically held that should be enough.
Or you could solder a good thick solid-core wire, then push it further through the board. If you stress it the track will likely fracture around the footprint of the solder. You can then pull the fracture back into place: looks like a good joint, but no connectivity.
Theo
Not sure what a desoldering station is, but I used my new solder sucker to great effect today.
Well, it's like your solder sucker except it's has a heated tip like a soldering iron (but hollow) and has a vacuum pump built in.
Place the tip on / over the joint for a second or so, pull the trigger, solder all gone (rinse - repeat). ;-)
Cheers, T i m
En el artículo , Adrian Caspersz escribió:
^ That.
Absolute s**te.
En el artículo , Tim Streater escribió:
A tip: when it clags up or stops sucking properly, clear it out and a squirt of silicone-based furniture polish (Mr Sheen etc) down the tube works wonders. And your PCBs come out all lemony fresh.
Or just very old components. The snag these days is that most things are surface mount soldered with flow technology. They used to say no more dry joints, but this was and still is a lie. I have a computer motherboard here that has a dry joint somewhere, when it is in the mind to do so, great loud thumps on current use and a touch of microphony exist, but as soon as a person gets ready to have a look no amount of proding will induce it. as its an old machine, then we live with it as its going to get scrapped. Therse sort of odd effects are hard to duplicat, and from the original post I got the impression that exact copies were needed. So I'd suspect this might well be impossible indeed half the issue wiill be making the device assembled show a fault that comes and goes realistically. From memory some of the hardest to find used to be those where a dry joint had made a semiconductor destroy itself, by, for instance losing half the bias on the base and hence conduct too much, as one could replace said part, but the joint in question could be on the earth side of a resistor and hence all would appear well till it went open circuit again and blew the semicondutore again later on. Had a tape deck that did this once, really irritating as it was a darlington pair. Brian
This lot so need training ...
eads so they can't be soldered too.
t things can be faked, I can blow up LEDs, transitors, etc or put the wron g value component in. But I want to create a dry joint the standard copper stripboards is a bit more of a problem, it can't be too messy or obvious a s I want them to fault find using a meter on continuity.
easy, rotate the wire slowly while it solidifies. Dry joint nearly every ti me.
NT
Ah, righto, ta. Well I was effectively that yesterday - soldering iron in one hand to melt, sucker in the other. Trouble is half the time I'd forgotten to press the sucker's plunger in so nothing happened. Got there in the end tho.
I was just wondering whether to pass that around, as I did so elsewhere a couple of days ago. The 'beautiful woman' bit is irritating too. Wrong part of iron, wrong side of board, no solder, and probably wrong safety specs.
And the other half of the time, when I did press it in, the plunger expelled the solidified solder, now very feathery, into the nozzle, ready to be melted again and dropped onto the spot I was trying to clear.
En el artículo , Adrian Caspersz escribió:
Oh dear.
tht is differnt I have a can of that too, it's main use is to stop oxidinsing rather than anti-solder stuff.
It might have that effect but I'm not sure thats the aim.
Yes that's the sort of joint I want. Students seem to be able to acheive this but I'm having problems doing it myself.
Yes me too, although I set our irons to 333C which seems OK.
I run on about 300, but I use 63/37.
HomeOwnersHub website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.